PRESENT’S OFFICE, REGIONAL ADMINISTRATION
AND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES
CHEMISTRY FORM THREE
MID-TERM EXAMS – AUG/SEPT – 2024
TIME: 2:30 HRS
INSTRUCTIONS
SECTION A
Answer all questions in this section
i. Which of the following groups consist of home Care products?
ii. An electric current of 0.2A was passed through an electrolyte for 16.67minutes. The quantity of electricity passed is;
iii. The copper (II) oxide reacts with hydrogen gas to form copper metal and water. What will be the mass of reduced element?
iv. During the steam reforming method in industrial preparation of hydrogen, the steam reacts with what compound to produce hydrogen gas?
v. Domestic utensil made up of iron rust easily as a result of the presence of:-
vi. What is the correct meaning of ionization energy?
vii. Which of the following pairs constitute the best methods for treating and purifying water?
viii. An electric current was passed through a concentrated solution of hydrochloric acid using carbon electrodes. The substance liberated at anode was.
ix. If element Q of group (H) combines with element R of group (IV) what will be the formula of the resulting compound.
x. The process of giving away water of crystallization to the atmosphere by a chemical substance is called.
2. Match the items in List A with responses in List B by writing the letter of the correct response beside the items number in the answer booklet provided.
LIST A | LIST B |
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SECTION B
Answer all questions in this section
3. You are provided with the following fuels fire woods, natural gas, charcoal and kerosene.
4. (a) Students are advised to use a non- luminous flame for heating in the laboratory
(i) Explain how a Bunsen burner produces a non- luminous flame
(ii) Give a reason as to why advice above given to students.
(iii) What are the functions of the air holes and barrel in the Bunsen burner?
(b)Why hydrogen peroxide preferred to potassium chlorate during preparation of oxygen gas?
(c) Why iron is not usually recommended in construction of steam pipes and boilers?
(d) What would happen to a well stoppered bottle full of water left in deep freezer over night? Why does this happen.
5. (a) Neutralization is applied in various useful situations with the aid of balanced chemical equation where necessary; describe any four usefulness of neutralization.
(b) 2.91 g of a monobasic acid, HX, were dissolved in water and made up to 250 cm3 with water. This solution was titrated with 0.108 M sodium hydroxide solution. 25 cm3 of the sodium hydroxide solution required 22.5 cm3 of the HX solution for complete neutralization. The equation for the reaction is.
HX (aq) + NaOH(aq) → NaX(aq) + H2O(l)
(a) Calculate the concentration in (i) g l-1 (ii) mol l-1 of the acid.
(b) Calculate the molar mass of HX.
6. (a) Janeth heated compound “W” in a test tube and observed that a brown gas was produced, residue X formed. Also when she inserted a glowing splint into the test tube rekindled.
7. (a)Sodium chloride (NaCI) and hydrogen Chloride (HCI) are both chloride Compounds.Differentiate the two compounds by giving three reasons.
(b)(i)Differentiate empirical formula from molecular formula. cetain compound formed by Sulphur and Oxygen contains 40.1% sulphur by mass.Workout the empirical formula of this compound.
8. (a) 25cm3 of 0.1MHCl were neutralized by 23cm3 of Na2CO3 solution. Calculate the concentration of the alkali in grams per litre.
(b)Suggest a suitable indicator of each of the following titrations
9. (a)What do you understand the term chemical equation?
(b)Write ionic equation for the following chemical reactions.
10. (a)Explain the meaning of each of the following terms.
(b)The industrial oxidation of Sulphur dioxide is summarized in the equation below.
2SO3(g) + O2(g) 2SO3(g) H=-94.9 Kjmol-1
What will be the effect of each of the following on the production of Sulphur trioxide?
(c)Briefly explain how each of the following factors affects the rate of a chemical reaction.
(d)Give one good reason for the following
SECTION C
11.
FORM THREE CHEMISTRY EXAM SERIES 176
FORM THREE CHEMISTRY EXAM SERIES 176
PRESIDENT’S OFFICE, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES,
TERMINAL EXAMINATION-MAY-2024
CHEMISTRY FORM THREE
Time: 3Hours
Instructions
SECTION A: (16 MARKS)
Answer all questions in this section.
What is the Molarity of this solution?
2. Match the colour formed in LIST A with the corresponding metal burning in air in LIST B
LIST A | LIST B |
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SECTION B: 54 MARKS
ANSWER ALL QUESTIONS
3. (a) The table below shows two brands of bottled water for drinking and the concentration of different mineral ions in each brand. Study the table and answer the questions below it.
Composition in mg/Litre | Mineral | Na+ | Ca2+ | Mg2+ | Cl | NO3 | SO42- | Fe2+ | F |
Uhai | 40.0 | 3.05 | 4.15 | 14.18 | 0.48 | 10.0 | 0 | 1.76 | |
Dasani | 22.32 | 2.69 | 0.11 | 6.50 | 1.0 | 8.0 | 0 | 0.45 |
(i) Which brand of water is more hard? Explain.
(ii) State the benefit of having calcium ions in water;
(iii)Tap water is usually treated before being used. State what is added to perform that function.
(b) Hydrogen and phosphorus are non-metallic elements
(i) Which one between the two atoms is more electropositive?
(ii) Show your work clearly, write the chemical formula and the name of the compound formed when the two atoms combine.
4. (a) Define the following terms
(i) Mole
(ii) Molar mass
(b) 112 dm3 of oxygen gas was collected at S.T.P when a sample of lead nitrate was completely decomposed by heat. Calculate the volume of nitrogen dioxide produced.
5. One of the methods used for the preparation of oxygen is by the decomposition of hydrogen peroxide as shown in the reaction equation below
2(g)
(a) (i) What is the purpose of MnO2 in the reaction?
(ii) What will happen to the rate of the reaction if MnO2 is not used in the above reaction?
(b) Briefly explain how the gas produced from the chemical reaction above is tested
6. Element R having atomic number 20 combines with element S having atomic number 17 to form a certain compound
a) Write the formula of the compound and state the type of bond formed in the compound
b) Give any three properties of the compound formed in 7(a) above
7. Mr Kalubandika wanted to know some chemistry pertaining concepts. Help Mr Kalubandika to answer the following conceptual questions.
a) In which other areas do we find the warning signs out of laboratory (give four point)
b) Explain how measurements of volume differ when using measuring cylinder and burette
c) It is recommend that laboratory apparatus should be properly washed or wiped after use, explain the significance for this when
i. Measuring volume of liquids
ii. Measuring mass of substance
8. (a) A gaseous compound consists of 86% Carbon and 14% Hydrogen by mass. At S.T.P, 3.2dm3 of the compound had mass of 6g.
(i) Calculate its molecular formula
(ii)Give the IUPAC name of the compound
(b) Most of the apparatus in the laboratory are made up of glass materials. Support this statement by giving ant two (2) reasons. (07 Marks)
9. (a) When an acid is reacted with base, it forms salt and water. Using your knowledge of chemistry, explain how will you apply this reaction in your daily life? Give any four points.
(b) Insoluble salts are the salt that does not dissolve in water. Name any three examples of salts that are insoluble in water. (07 Marks)
10. 5.3g of X2CO3 was dissolved in water to make 0.5 litre of a solution. 25cm³ 0f this solution required 50.0cm³ of 0.1M HCl for complete neutralization.
a) Write the balanced chemical equation for the reaction
b) Calculate the concentration of X2CO3 in mol/dm3
c) Calculate the relative molecular mass of X2CO3
d) Calculate the relative atomic mass of X
e) What is the name and symbol of element X
11. (a)What are the four (4) stages for extraction of moderate reactive metals is termed as reduction process. Explain why?
(b)Extraction of metals is termed as reduction process. Explain why?
(c)In certain areas iron can be extracted through blast furnace which involve different temperatures such as 1000°C, 750°C and 250°C in different stages.
(d) What are the two (2) environmental effects caused by extraction of metals?
FORM THREE CHEMISTRY EXAM SERIES 171
FORM THREE CHEMISTRY EXAM SERIES 171
PRESIDENT’S OFFICE, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES,
MID TERM ONE – MARCH-2024
CHEMISTRY FORM THREE
Time: 3Hours
Instructions
SECTION A: (16 MARKS)
Answer all questions in this section.
LIST A | LIST B |
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SECTION B
54 MARKS
Answer all questions.
b) Comment on the following statement
B) Differentiate between suspension and solution
Composition mg/ litre | mineral | Na+ | Ca2+ | Mg2+ | Cl- | No3-1 | So42- | Fe2+ | F-1 |
| Uhai | 40 | 3.05 | 4.15 | 14.18 | 0.48 | 10.0 | 0 | 1.76 |
| Dasani | 22.32 | 2.69 | 0.11 | 6.5 | 1.0 | 8.0 | 0 | 0.45 |
b) Hydrogen and phosphorus are non metallic elements
b) Define the terms below
b) Explain why hydrogen is proffered to potassium chloride during preparation of oxygen gas.
b) Write a balanced and ionic equation for reaction between sodium carbonate and hydrochloric acid
c) Differentiate ionic equation from molecular equation
SECTION C
30MARKS
b) We have coal in Kuwira Mbeya region; the government authorities have allowed the use of coal for domestic and industrial purposes. What warning can you raise concerning the likely effects? Give five points
b) State weather the following is permanent change or temporary change
FORM THREE CHEMISTRY EXAM SERIES 160
FORM THREE CHEMISTRY EXAM SERIES 160
PRESIDENT OFFICE REGIONAL ADMNISTRATIONAND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES
COMPETENCE BASED ASSEMENT
032/1CHEMISTRY FORM THREE
ANNUAL EXAMINATIONS – 2023
Time: 3 Hours
Instructions
Atomic masses:
H=1,C=12,O=16,N=14,Ag=108
Avogadro’s number = 6.02 x 1023
GMV at s.t.p = 22.4 dm3
1 Faraday = 96,500 coulombs
Standard pressure = 760 mm Hg
Standard temperature = 273 K
1 litre = 1dm3= 1000cm3
SECTION A. (16 MARKS)
LIST A | LIST B |
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SECTION B. (54 Marks)
Attempt all questions in this section
(b) An organic compound P consists of 52.2% carbon 13% hydrogen and 34.8% Oxygen. The vapour density of P is 23. Calculate molecular formula of the compound.
(c) Calculate Oxidation number of Nitrogen in potassium nitrate.
(b) 20.0cm3of sodium hydroxide containing 8.0gdm3was required for complete neutralization of 0.18g of dibasic acid. Calculate the relative molecular mass of the acid
(b) Dilute Silver Nitrate solution was decomposed by passage of electric current through it. What mass of Silver and what volume of Oxygen (measured at (STP) would be liberated in electrolysis by 9650C of electricity?
(b)Consider the equation below for dissociation of Suphuric acid
H2SO4(aq)→ 2H(aq)++ SO42-(aq)
From equation, how many ions are there in 9.8g of sulphuric acid?
16O8,19F9,20Ne1023Na1124Mg12. Atoms and ions of these elements can be 150-electronic (have same number of electrons)
(b)Although Sulphur dioxide is an Oxide, It can be further Oxidized
SECTION C (30 Marks)
Answerany twoquestions from this section
(b) State four uses of sodium metal
(b) Fire extinguisher is used to stop fire. List five types of fire extinguishers
(b) With the acid of chemical equation, briefly describe the following processes
FORM THREE CHEMISTRY EXAM SERIES 158
FORM THREE CHEMISTRY EXAM SERIES 158
PRESENT’S OFFICE, REGIONAL ADMINISTRATION
AND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES
CHEMISTRY FORM THREE
MID-TERM EXAMS – AUGUST – 2023
TIME: 2:30 HRS
INSTRUCTIONS
SECTION A
LIST A | LIST B |
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SECTION B (54 Marks)
Answer all questions
(b) If 0.5g of hydrogen gas in exposed to air. What mass of water will be formed?
(b)Explain the following Observation
(b)Element U has atomic number 12 while element V has atomic number 16. How do the melting points of their oxides compare. Explain
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K | L | M |
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(a)(i)Select element which belong to the same chemical family
(ii) Write the formula of ions for elements in the same period
(b)The first ionization energies of two elements K and M at random are 577 Kjlmol and 494KJlmol
(b)State the main raw materials and process involved in manufacture of each of the following products
(b)The industrial Oxidation of sulphur dioxide is summarized in equation below
2SO3(g) + O2(g) 2SO3(g) ∆H=94.9 KJlmol
What will be the effect of each of the trioxide?
(c)Give one good reason for the following
(b)Dilute silver nitrate solution was decomposed by the passage of electric current through it. What mass of Silver and what volume of Oxygen measured at Stp would be liberated in electricity?
FORM THREE CHEMISTRY EXAM SERIES 140
FORM THREE CHEMISTRY EXAM SERIES 140
PRESIDENT OFFICE REGIONAL ADMNISTRATION
AND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES
COMPETENCE BASED ASSEMENT
CHEMISTRY FORM THREE
TERMINAL EXAMS MAY – 2023
032/1
Time: 3 Hours
Instructions
Atomic masses:
H=1, C=12, O=16, N=14, Pb=108
Avogadro’s number = 6.02 x 1023
GMV at s.t.p = 22.4 dm3
1 Faraday = 96,500 coulombs
Standard pressure = 760 mm Hg
Standard temperature = 273 K
1 litre = 1dm3 = 1000cm3
SECTION A
(i) The best chemical warning signs that should be put on bottles containing kerosene is ……….
(vii) What volume of hydrogen gas will be produced when 1.3g of zinc granules react completely with excess dilute sulphuric acid at s.t.p?
(x) The following reaction 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O (l) is an example of a
(iv) 10cm3 of 0.4M Sodium Hydroxide are added to 40cm3of 0.2M hydrochloric acid. The resulting mixture will be
(viii) A metal nitrate which will not give a metal oxide on heating is:
(ix) When nitrogen gas is formed covalently how many electrons are shared between nitrogen atoms.
(x) The following is an example of organic acid
LIST A | LIST B |
(i) Methyl orange indicator (ii) Calcium hydroxide (iii) pH 2 (iv) Neutralization reaction (v) Sodium hydrogen sulphate |
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SECTION B. (70 MARKS)
ANSWER ALL QUESTIONS FROM THIS SECTION
(b) 2FeCl3(aq) + H2S(g) → 2FeCl2(aq) + 2HCl + S(s)
From above equation, calculate the mass of iron (II) Chloride formed by the excess of hydrogen sulphide gas on a solution containing 54.0g of iron (III) chloride.
(b)Find the concentration in molarity of 2.70g of Sodium carbonate dissolved in 250cm3
If 1.5 litres of chlorine measured at S.T.P were produced, what volume of oxygen would also be produced? What mass of copper was produced?
will proceed forward or backward under these conditions:
(b)What is the role of Silica gel in Haber process?
(c)Vanadium pentoxide is generally used as a catalyst in the contact process
Comment
(d) A catalyst can shift the position of a chemical equilibrium. Comment.
SECTION C. 15 MARKS
ANSWER QUESTION 11.
FORM THREE CHEMISTRY EXAM SERIES 128
FORM THREE CHEMISTRY EXAM SERIES 128
PRESIDENT OFFICE REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES
COMPETENCE BASED ASSESSMENT
032/1 CHEMISTRY FORM THREE
NEW NECTA FORMAT-2023
MID-TERM EXAMS MARCH – 2023
Time: 3:00 Hours
Instructions
SECTION A (16 Marks)
1. For each of items (i) – (x), Choose the correct answer from among the given alternative beside item number in answer booklet provided
2. (a)Match the terms in List A with explanation on List B and write the answer on spaces provided.
LIST A | LIST B |
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SECTION B (54 Marks)
Answer all questions in this section
3.
4. (a)Give the meaning of the following
(b)Categorize the following salts
5.
6. Soap solution of different amount of water are tested from four different sources and produces lather observed for 30 seconds. The three groups of water were untreated, Boiled and Treated by ion exchange. The results were as follows.
Sample | Untreated | Boiled | Passed though |
| 12 | 1.8 | 1.8 |
| 17 | 17 | 1.7 |
| 26 | 20 | 1.8 |
| 1.6 | 1.6 | 1.6 |
Use above results to answer question that follow
7. (a) Define chemical equation and give two importance’s
(b) Write product and balance the following chemical equations
8. (a)List down three(3) sources of Natural water
(b)Explain why water is Not used to extinguish classic E fires
(c)Give reason to Support the fact
SECTION C (30 Marks)
Answer Any two Questions
9. (a)Define molecular and Empirical formula
(b)A compound oxygen M is composed of 52.2% carbon, 13% hydrogen and the rest Oxygen. If molecular mars of M is 4
10. With aid of diagram illustrate/Describe sit methods of separating mixtures
11. Most areas in Dar es Salaams have problem of water hardness which affect much of their life. As an expert explain how you can help them solve the problem
FORM THREE CHEMISTRY EXAM SERIES 117
FORM THREE CHEMISTRY EXAM SERIES 117
THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
COMPETENCY BASED SECONDARY EXAMINATION SERIES
032/1 CHEMISTRY FORM THREE
TIME: 2 HOURS NOVEMBER 2022
INSTRUCTIONS
SECTION A. (20 MARKS)
1. For each items (i)-(x) choose the correct answer among the given alternative and write the letter beside the item number in the booklet provided
(i) Which of the following is the agricultural product made by the application of chemistry?
(ii) When methane undergo substitution reaction with excess chlorine .what is the end product
(iii) An element X is found in period 4; group II of the periodic table .if the element X Undergo the reaction X→X 2+ +2e - ; the electronic configuration of X ion formed will be A. 2: 8:6 B. 2:6 C. 2:8:4 D. 2:8:8:2 E. 2:8:8
(iv) A current of 0.2A was passed through an electrolyte for 16 minutes and 40 seconds .what is the quantity of electricity produced in coulombs.
A. 2000C B. 1000C C. 200C D. 0.2C E. 7686C
(v) Which carbonate is the most stable to heat?
(vi) Skin injury that cause a change in the colour of skin
(vii) A good fuel is the one which has.
(viii) The region of the atmosphere which contains the ozone layer is called
(ix) Aluminum is said to be amphoteric oxide because
(x) The main impurities in Nitrogen gas prepared in the laboratory are:-
2. Match the item in LIST A with a correct response in LIST B by writing the letter of the response below the corresponding item in the table given
LIST A | LIST B |
(i) A gas that forms explosive mixture with air and water (ii) A gas that forms a reddish brown fumes when comes in contact with air (iii) A gas that turns lime water milky (iv) A colorless gas that bleaches moist coloured flower (v) Only basic gas |
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SECTION B. (70MARK)
Answer All questions in this section
3. (a) A stone is said to be a good example of matter. Give two reasons to support this fact.
4. (a) Identify the substances by using the following information.
5. (a) outline three reasons to explain why Carbondioxide is used to extinguish fir
(b) A sample of mass 28.6g of hydrated sodium carbonate ( Na 2 CO 3 .10H 2 O) was heated such that; its water was entily absorbed by 32g of anhydrous copper II sulphate to form a blue compound of hydrated( CuSO 4 .XH 2 O) .find the value of X in the copper sulphate.
6.(a)A student aimed to prepared a gas X by reacting a moderate reactive metal with a dilute acid .use this information to answer the following question
(b) State four properties that make Aluminium useful in overhead cables
7. (a) Calculate the morality of 5% by weight of a solution of sodium hydroxide
(b) What is the simplest chemical formula of a compound formed when 36g of Magnesium combine with 14g of Nitrogen?
8.. (a) During electrolysis of an aqueous solution of salt of metal M , a current of 2.0A was passed for 32minutes and 10 second .the mass of metal M deposited was 2.24g.
(b)During electrolysis of brine .Sodium is deposited at the cathode and chlorine gas is released at the anode .if 2.0g of sodium are collected at the cathode .find the volume of chlorine released at S.T.P.
9. (a) State the le-chatelier’s principle
2SO 2 (g) + O 2 (g) ⥫⥬ 2SO 3 (g) ∆H = -94.4KJMol -1 If
(c)Briefly write one application of le- chatelier’s principle.
9. (a) States any three main physical properties of water and show the usefulness of each property
(b)During large – scale treatment of water, what two chemical are added at various stage?. Explain their use.
10. (a) i. Extraction of metal is said to be reduction process. Explain
ii. Why Sodium is collected by upwards in the down cell?
(b) Describe the use of each of the following during extraction of sodium
11. (a)State the modern periodic law
(b)Study the periodic table below then answer the questions that follow.
Write the formula of compounds formed when element
Draw and write electronic configuration of Y.
12. (a)Catherine is planning to make fire for cooking ugali for her family. What are necessary conditions which must be present so that she can make fire successfully for cooking ugali for her family?
(b)Give a reason for each of the followings
SECTION C (15 MARKS)
Answer only one (1) question.
13. (a)Give good reason (s) for the following. (Answer according to the question demand).
(b) State the main raw materials and process involved in the manufacture of each of the following products.
14. (a) 25cm 3 of 0.1MHCl were neutralized by 23cm 3 of Na 2 CO 3 solution. Calculate the concentration of the alkali in grams per litre.
(b)Suggest a suitable indicator of each of the following titrations
FORM THREE CHEMISTRY EXAM SERIES 104
FORM THREE CHEMISTRY EXAM SERIES 104
THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
COMPETENCY BASED SECONDARY EXAMINATION SERIES
CHEMISTRY-SEPT 2022
FORM THREE
032
Time:3 Hours SEPT, 2022
Instructions
questions.
Atomic masses: H = 1, O = 16, C = 12, N = 14, Na = 23, Cl = 35.5, K = 39
Ca = 40
Avogadro’s number:
GMV at s.t.p =
1 Faraday = 96,500 coulombs.
Standard pressure = 760 mm Hg.
Standard temperature = 273 K.
1 litre ==
SECTION A (15 Marks)
Answerall questions in this section.
A: spirit lampB:gas stoveC:kerosene stove
D:candleE:hurricane lamp
A: it is commonly known liquid
B:it exists in all three states of matter
C:it dissolves more substances than any other known liquid.
D:it is used for cooking, drinking and washing bodies and clothes
E:it is colourless, odourless and tasteless liquid
A:dilute hydrochloric acid B: cucumber C:lemon
D:tamarind E:blueberries
A:group I period 3B:group VII period 2 C:group I period 7
D: group VII period 1E:group VII period 3
A:condensationB:meltingC:evaporation
D:sublimationE:deposition
A:evaporating dishB:test tube holderC:deflagrating spoon
D:gas jarE:desiccator
A:sodium metalB:alloyC:water vapour
D:oilE:grease
A:fractional distillationB:filtrationC:condensation
D:crystallizationE:simple distillation
A:+1B:4C:-1D:+4E:-2
A:aluminiumB:calciumC:sodium
D:potassiumE:both A and C
List A | List B |
| A:Electrovalent compound B:Potassium C:Bromine D:Covalent compound E:Phosphate F:Noble gases G:Metalloids |
SECTION B (70 Marks)
Answerall questions in this section
(a)(i)Write the actual names of element X, Y and compound Z.
(ii)What is the chemical combination involved in this interaction?
(b)(i)Draw the structure of the compound Z
(ii)Give two properties of compound Z.
three reasons to support this statement.
(b)With the help of balanced chemical equation, explain what will happen to:
(i)A piece of iron bar left to the exposure.
(ii)Anhydrous copper (II) sulphate when put into the watch glass and placed
on the laboratory bench.
(ii)Write the symbols of phosphorous, fluorine, manganese and copper.
(b)Why some elements are assigned symbols with only one letter while
Others bear with two letters?
Chloride hexahydrate.
(ii)Why laboratory safety precaution is very important?
(b)Categorize the following laboratory compounds into corrosive and flammable:
Sodium hydroxide, spirit, sulphuric acid, oil, aro and benzene
bythermal decomposition of potassium chlorate. If he used 20g of potassium
chlorate, what volume of oxygen would be produced at s.t.p?
products.
wood.
(b)(i)“Liquid fuel is more advantageous than solid fuel”. Give three points to
support this statement.
(ii)Write down the composition of water gas and producer gas.
Write the reactions which take place at the electrodes and give reason why
the solution becomes alkaline.
electricity for one and a half hours?
SECTION C (15 Marks)
Answerone (1) question in this section.
Page1 of5
FORM THREE CHEMISTRY EXAM SERIES 96
FORM THREE CHEMISTRY EXAM SERIES 96
THE PRESIDENT’S OFFICE
MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
COMPETENCE BASED SECONDARY EXAMINATION SERIES
CHEMISTRY TERMINAL EXAMINATION
FORM THREE-2022
Time: 3 Hours
Instructions.
Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.
Avogadro’s number = 6.02 x 1023
GMV at s.t.p = 22.4dm3
1 faraday = 96,500 coulombs.
Standard temperature = 273K
Standard pressure = 760mmHg.
1 Litre = 1 dm3 = 1000cm3
SECTION A ( 15 Marks)
Answer all questions in this section.
1. For each of the items (i)-(xv), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.
2. The following are the matching items .Match the correct item in LIST B corresponding one from LIST A. Write the letter in answer sheet provided.
LIST A | LIST B |
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SECTION B ( 70 Marks)
Answer all questions in this section.
ii. Is air a compound or mixture? Give four (4) reasons to support your answer.
b) State the methods of separating the following mixture. Give a reason to support your answer.
b) Give five (5) items found in the First aid kit and their uses.
c) What First aid do you give to a person who has fainted?
b) Complete and balance the following reaction.
b) i. State the Avogadro’s law.
ii. Mention two (2) applications of Avogadro law
b) List three chemical properties of oxygen.
b) What is fuel?
c) State four (4) the characteristics of good fuel.
b) i. What is an electronic configuration?
ii. Give three (3) applications of electronic configuration.
b) i. What is flame?
ii. Differentiate between luminous and non-luminous flame. Give four (4) points.
b) Explain four (4) economic importance of water.
SECTION C ( 15 Marks)
Answer one (1) question from this section.
b) Calculate the number of moles in each of the following substances
c) Calculate the number of ions present in 30g of Aluminum sulphates.
14. With the aid of a chemical equation, describe how you would prepare pure solid sodium chloride by the action of an acid and a base.
FORM THREE CHEMISTRY EXAM SERIES 83
FORM THREE CHEMISTRY EXAM SERIES 83
THE PRESIDENT’S OFFICE
MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
COMPETENCE BASED SECONDARY EXAMINATION SERIES
CHEMISTRY MID TERM EXAMINATION
FORM THREE-MARCH/APRIL-2022
Time: 3Hours
Instructions.
Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.
Avogadro’s number = 6.02 x 1023
GMV at s.t.p = 22.4dm3
1 faraday = 96,500 coulombs.
Standard temperature = 273K
Standard pressure = 760mmHg.
1 Litre = 1 dm3 = 1000cm3
SECTION A (15 Marks)
Answer All questions in this section.
(vi) Which one of the following sets of elements is arranged in order to increase
electro negativity starting with the least one?
SECTION B.
List A.
List B.
SECTION B (70 Marks)
Answer all questions in this section
(b) Give two examples of each of the following:
(i) Solid fuel ………………………………….., ……………………………..
(ii) Liquid fuel…………………………………..,……………………………...
(iii) Gaseous fuel ……………………………….., …………………………….
(c) Name four characteristics of a good fuel
(i) ………………………………………………………………………………
(ii) ………………………………………………………………………………
(iii) ……………………………………………………………………………..
(iv) ……………………………………………………………………………..
(b) Study the apparatus arranged below and answers the questions below.
E…………………………………………………………………..
(ii) Write down the valence of the following elements:
Magnesium …………………………………. Lithium ……………………………
(iii) Name the following radicals and state their valences
Radical | Name | Valence |
NH4+ |
|
|
CO 32 - |
|
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HCO3- |
|
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SO32 |
|
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SO2 4- |
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NO 3- |
|
|
(b) Write the following compounds
(i) Aluminium oxide ………………………………………………………………
(ii) Lead (II) nitrate ……………………………………………………………..…
(iii) Ammonium carbonate …………………………………………………………
(iv) Lead (II) sulphide ……………………………………………………………..
(v) Copper (II) hydroxide …………………………………………………………
(b) A certain gaseous compound contains 82.8% of carbon and 17.2% of hydrogen by mass. The vapour density of the compound is 29. Calculate its molecular formula (C = 12, H = 1)
(b) Give four uses of hydrogen gas
(i) ……………………………………………………………………………….
(ii) ………………………………………………………………………………
(iii) ……………………………………………………………………………..
(iv) ……………………………………………………………………………..
(b) Chlorine has two isotopes of chlorine – 35 3517 Cl, which constitutes of 75% in the mixture and chlorine – 37 3717 Cl, which constitutes of 25%. Calculate the relative atomic mass of chlorine.
(c) One of the methods of preventing iron from rusting is sacrificial protection,
why it is called so ……………………………………………………………………………………………………………………………………………………………………………………
9. (a) Give the meaning of the following terms
(i) Solution ……………………………………………………………………………..
(ii) Emulsion ……………………………………………………………………………
……………………………………………………………………………………
(iii) Potable water ………………………………………………………………………
…………………………………………………………………………………….
(b) State the modern periodic table
………………………………………………………………………………………………………………………………………………………………………………………………
(c) Name heat sources used in the laboratory
(i) ………………………………………………………………………………
(ii) ……………………………………………………………………………..
(iii) ……………………………………………………………………………
(iv) ……………………………………………………………………………
10. (a) Show how the following change in the periodic table:
(i) Electronegativity ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
(ii) Ionization energy ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
(iii) Atomic size ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
(b) “Chemistry is the useless subject” Discuss the above statement with reasons
(i)……………………………………………………………………………………………
…………………………………………………………………………………………
(ii) …………………………………………………………………………………………..
…………………………………………………………………………………………..
(iii) …………………………………………………………………………………………
………………………………………………………. ………………………………..
(iv) …………………………………………………………………………………………
…………………………………………………………………………………………
11. a) What is the hardness of water?
b) Briefly explain types of hard of water.
c) State the causes of hardness of water for each type mention in (b) above.
d) Explain how you would remove the hardness of water according to its type.
e) Give three (3) advantages and three (3) disadvantages of the hard water.
12. Balance the following equations:
(i)Ca + H3PO4→ Ca3(PO4)2 + H2
13. Give the name of the types of reaction represented by each of the following chemical equations.
(iii)Zn(s)+CuS04(aq) —>ZnSO4(aq) +CU(S)
14. Complete the following equations and determine the type of chemical reaction involved in each case.
(i) Zn(s)+ H2SO4(aq)→
(i) AgN 03(aq) + NaCl(aq)→
(iii) N2(g) + H2(g) →
FORM THREE CHEMISTRY EXAM SERIES 74
FORM THREE CHEMISTRY EXAM SERIES 74
THE PRESIDENT’S OFFICE
MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES
CHEMISTRY ANNUAL EXAMINATION
FORM THREE-NOVEMBER 2021
Instructions
H 1, C = 12, 0=16, N = 14, Cu = 64, Pb = 108.
A vogadros number = 6.02 x 1023.
GMV at s.t.p = 22.4 dm3.
1 Faraday = 96,500 coulombs.
Standard pressure = 760 mm Hg.
Standard temperature = 273 K.
1 litre = 1 dm3 = 1000 cm3.
SECTION A (20 Marks)
Answer all questions in this section.
1. For each of the items (i) (x), choose the correct answer from the given alternatives and write its letter beside the item number.
(i) Which of the following is an agricultural chemical products made by the application of chemistry?
(ii) A current of 0.2 A was passed through an electrolyte for 16 minutes and 40 seconds. What is the quantity of electricity produced in coulombs?
(iii) Substance X liberates chlorine gas from acidified potassium chloride. The behaviour of X is described as:
(iv) Which carbonate is the most stable to heat?
(v) Aluminium does not react with water and does not corrode much in air because
(vi) Which of the following compounds does NOT belong to the alkenes homologous series?
(vii) In the following equilibrium equation, 2S02(g) +O2(g) 2S03 The forward reaction is exothermic. Which change would increase the production of sulphur trioxide at equilibrium?
(viii) When a burning fuel produces blue color it means there is
(ix) Which of the following equations represents the combustion of methane with the products collected at 120oC?
(x) Which of these can be reduced when heated with carbon?
2. Match the items in List A with the responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided. Match the items in List A with the responses in List B by writing the letter of the correct
List A | List B |
|
|
SECTION B (70 Marks)
Answer all questions in this section.
3. (a) Define the following terms:
(b) State three main physical properties of water and show the usefulness of each property.
(c) State three industrial application of electrolysis.
4. (a) Copper obtained from copper pyrites (CuFeS2) is impure for electrical wiring and has to be purified by electrolysis.
(i) Name the electrolyte and the electrodes used during electrolysis.
(ii) Write the observations that can be made during the electrolysis.
(b) The following flow diagram shows the stages in the contact process
(i) Give the names of element A, catalyst B and an acid C.
(ii) Write a balanced chemical equation for the formation of sulphur trioxide in stage 2
5. (a) Suggest one method of separating each of the following:
(i) Green solution from leaves.
(ii) Alcohol from water.
(b) Elements K, L, M and N have atomic numbers 6, 8, 9 and 20 respectively. Classify each element into its respective period and group.
6. (a) Give one example in each of the following:
(i) Alkali earth metals.
(ii) Noblegases .
(iii) Transition elements.
(b) Write the names of the following processes of changing matter from one state to another.
(i) Gas to liquid.
(ii) Ga s to solid.
(iii) Solid t o gas .
7 (a) Define the following:
( i ) Mole .
( i i ) Molarmass .
(b) 112 dm3 of oxygen gas was collected at s.t.p when a sample of lead nitrate was completely decomposed by heat. Calculate the volume of nitrogen dioxide gas produced.
8. (a) Identify and state the environmental problem caused by the gas which is released from the blast furnace in the extraction of iron from its oxide.
(b) The following equation shows the reaction between hydrogen and iodine gas to form hydrogen iodide gas,H2(g) + I2(g) ↔ 2HI (g) ∆H= -800Kj/mol. Giving a reason, explain what would happen to the position of equilibrium if
(i) temperature is lowered.
(ii) hydrogen iodide gas is pumped into the system.
9. (a) Name two elements which are expected to show similar chemical reaction with magnesium. What is the basis for your choice?
(b) State the main raw material and the process involved in the manufacture of the following products.
(c) (i) Name the compound which causes temporary hardness of water and the compound which causes permanent hardness of water.
(ii) Write one balanced chemical equation in each case to show how to remove temporary and permanent hardness of water.
10. (a) Suggest one best method for separating each of the following mixtures:
(i) Common salt and water
(ii) Iodine and sand.
(iii) Pieces of iron and sand.
(b) Carbon dioxide can be prepared by adding an acid to calcium carbonate.
(i) Using a named acid, write a balanced chemical equation for the reaction. (ii) Name all the products formed in (b) (i).
11 . ( a ) With the aid of a chemical equation, describe how you would prepare pure solid sodium chloride by the action of an acid and a base.
(b) (i) Why petroleum and coal are non-renewable sources of energy?
(ii) Give three alternatives to non-renewable sources of energy.
12. Three moles of nitrogen gas combine with five moles of hydrogen gas to form ammonium gas by Haber process.
SECTION C (15 Marks)
Answer one (1) question in this section.
13.(a) Give three advantages of using chemical equations over word equations.
(b) You are provided with a compound composed of 22.2% zinc, 11.6% sulphur, 22.3% oxygen, and the rest percentage is water of crystallization. Calculate the molecular formula of the compound if its molecular mass is 283.
14. Explain six measures for minimizing the environmental degradation caused by extraction of metals in Tanzania.
FORM THREE CHEMISTRY EXAM SERIES 70
FORM THREE CHEMISTRY EXAM SERIES 70
THE PRESIDENT’S OFFICE
MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
COMPETENCE BASED SECONDARY EXAMINATION SERIES
CHEMISTRY 1MID TERMEXAMINATION
FORM THREE-AUGUST/SEPT-2021
Time: 3Hours
Instructions.
Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.
Avogadro’s number = 6.02 x 1023
GMV at s.t.p = 22.4dm3
1 faraday = 96,500 coulombs.
Standard temperature = 273K
Standard pressure = 760mmHg.
1 Litre = 1 dm3 = 1000cm3
SECTION A (15 Marks)
Answer All questions in this section.
1. For each of the items (i)-(xv), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.
(i)Why oxygen differs from other gases?
(ii) Why is hydrogen gas collected over water and by upward delivery method?
(iii) The following are the uses of chromatography except:
(iv) Which statement is the most correct about chemistry laboratory?
(v) Which carbonate is the most stable to heat?
(vi) In the following equilibrium equation, 2S02(g) +O2(g) 2S03 The forward reaction is exothermic. Which change would increase the production of sulphur trioxide at equilibrium?
(vii) Which of these can be reduced when heated with carbon?
(viii) Which of the following is the electronic configuration of an element Y found in period 3 and group II of the periodic table?
(ix) Which of the following is NOT among the composition of air?
(x) If a stead current of 2 amperes was passed through an aqueous solution of iron (II) sulphate for 15 minutes, then the mass of iron deposited at the cathode will be:
2. Match the items in List A which the responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.
LIST A | LIST B |
|
|
SECTION B (70 Marks)
Answer all questions in this section.
3. An atom of element X having atomic number 11 combines with an atom of element Y haying atomic number 9 to form a compound.
(a) Write the formula of the compound and state the type of bond formed in the compound.
(b) Give four properties of the compound formed in 7(a). (7 marks)
(b)
4. Explain how to handle chemicals having the warning signs of flammable, corrosive, harmful, explosive and toxic in the laboratory.
5. (a) Copper obtained from copper pyrites (CuFeS2) is impure for electrical wiring and has to be purified by electrolysis.
(i) Name the electrolyte and the electrodes used during electrolysis.
(ii) Write the observations that can be made during the electrolysis.
(b) The following flow diagram shows the stages in the contact process
(i) Give the names of element A, catalyst B and an acid C.
(ii) Write a balanced chemical equation for the formation of sulphur trioxide in stage 2
6. (a) Copper can be obtained from the ore, copper pyrites (CuFeS2). The ore is heated in a limited amount of air giving the following reaction:
4CuFeS2 + 11O 2 ? 4Cu + 2Fe 2 O 3 + 8SO2 .
(i) Calculate the maximum mass of copper that can be obtained from 367 kg of copper pyrites.
(ii) State why the gaseous product from this reaction must not be allowed to escape into the atmosphere.
(b) State three industrial application of electrolysis.
7. A student attempted to prepare hydrogen gas by reacting zinc metal with dilute sulphuric acid. In this experiment zinc metal granules of about 0.5 cm diameter and 0.20 moles of acid were used.
The rate of formation of hydrogen gas was found to be slow.
(a)Explain three ways in which the rate of formation of hydrogen gas could be increased.
(b)If the student wanted 36 cm3 of hydrogen gas at s.t.p, what amount of the acid would be required.
8. (a) 20 cm3 of a solution containing 7 g dm-3 of sodium hydroxide were exactly neutralized by 25 cm3 of 0.10 M hydrochloric acid. Calculate the concentration of sodium hydroxide in moles per dm3.
(b) Give two examples in each of the following solution.
(i) Gaseous solution.
(ii) Solid solution.
9. The flow chart in Figure 3 shows the process of obtaining a sample of nitrogen gas. Study it and answer the questions that follow.
(a) Identify X (I mark)
(b) Write an equation for the reaction with heated copper turnings. (1 mark)
(c) Name an impurity in the sample of nitrogen gas. ( I mark)
10. (a) Name two ores in which sodium occurs.
(b) During extraction of sodium using the down's process, calcium chloride is added to the ore. Give a reason for the addition of calcium chloride. (1 mark)
(c) State two uses of sodium. ( I mark)
11. Figure 3 shows the apparatus used to burn hydrogen in air. Use it to answer the questions that follow.
State the role of substance X.
(ii) Give the name of the substance that could be used as X. (1 mark)
(iii) State the role of the suction pump. (1 mark)
(iv) Name the product Y formed. (1 mark)
(v) Give a simple physical test to prove the identity of Y. (1 mark)
(vi) State the difference between 'dry' and 'anhydrous'. (2 marks)
12. (a) Consider elements with atomic number 1, 11, 12 and 17.
(i) What are the types of oxides formed by elements with atomic number 11 and 12?
(ii) Write an equation which represents a reaction between the element with atomic number 1 and 17.
(iii) Write a balanced chemical equation between the oxide of the element with atomic number 11 and aqueous solution of the compound formed in 4 (a) (ii).
(b) Suggest one method for the separation of each of the following:
(i) Iodine and sand.
(ii) Green solution from leaves.
(iii) Alcohol and water.
(iv) Iron fillings and powdered calcium carbonate.
SECTION C (15 Marks)
Answer one (1) question in this section.
13. 25 cm3 of 0.1 M HCl were neutralized by 23 cm3 of sodium hydroxide solution. Calculate the concentration of the alkali in grams per litre.
14. Describe four common stages for the extraction of metals. Does the extraction of gold follow all four stages? Give reasons.
FORM THREE CHEMISTRY EXAM SERIES 58
FORM THREE CHEMISTRY EXAM SERIES 58
THE PRESIDENT’S OFFICE
MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
COMPETENCE BASED SECONDARY EXAMINATION SERIES
CHEMISTRY 1TERMINALEXAMINATION
FORM THREE-2021
Time: 3Hours
Instructions.
Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.
Avogadro’s number = 6.02 x 1023
GMV at s.t.p = 22.4dm3
1 faraday = 96,500 coulombs.
Standard temperature = 273K
Standard pressure = 760mmHg.
1 Litre = 1 dm3 = 1000cm3
SECTION A (20 Marks)
Answer All questions in this section.
1. For each of the items (i)-(xv), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.
(iv) A covalent bond is formed when
(v) A solvent can be obtained from a solution by
(vi) Aqueous sugar solution is a poor conductor of electricity because
(vii) In order to produce the greatest amount of hydrogen in a short time, one gram of magnesium ribbon should react with
(viii) Fractional distillation process of a mixture of water and ethanol is possible because
(ix) Which of the following substances represent a group of acidic oxides?
(x) What will the molarity of a solution which contains 26.5 g of anhydrous sodium carbonate in 5 dm3 of solution?
2. Match the items in LIST A with the responses in LISTB by writing the letter of the correct response beside the item number in the answer booklet provided.
LIST A | LIST B |
|
|
SECTION B (70 Marks)
Answer all questions in this section.
3. Hydrogen has can be prepared by passing steam over heated magnesium ribbon as shown in the figure 2.
(a) Write an equation for the reaction that produces hydrogen gas.
(b) Explain why the delivery tube must be removed from beneath the water before heating is stopped.
(c) Explain why sodium metal is not suitable for this experiment.
4. A solution contains 40.3g of substance XOH per litre .250.0cm3of this solution required 30.0cm3 of 0.3M sulphuric(VI)acid for complete neutralisation.
(a) Calculate the number of moles of XOH that reacted.
(b) Determine the relative atomic mass of X.
5. (a) Explain the following observations:
(i) The colour of aqueous copper(ii) sulphate fades when a piece of magnesium metal is dropped into the solution.
(ii) A piece of iron bar is coated with a brown substance when left in the open on a rainy day.
6. A mass of 1.24g of a divalent metal was deposited when a current of 6A was passed through a solution of a metal sulphate for 12 minutes.Determine the relative atomic mass of the metal( Faraday = 96,500 C mol-1
(d) State two application s of electrolysis.
7. 30.0 cm3 of aqueous sodium hydroxide containing 8.0 g per litre of sodium hydroxide were completely neutralised by 0.294 g of a dibasic acid. Determine the relative formula mass of the dibasic acid. (Na = 23.0 ; O = 16.0 ; H 1.0)
8(a). Using iron filings, describe an experiment that can be conducted to show that oxygen is present in air.
(b) Element U has atomic number 12 while element V has atomic number 16. How do the melting points of their oxides compare? Explain. (3 marks)
9. (a) Name two ores of iron.
(b) Describe how the amount of iron in a sample of iron(III) oxide can be determined.
10.(a) Give three advantages of using chemical equations over word equations.
(b) You are provided with a compound composed of 22.2% zinc, 11.6% sulphur, 22.3% oxygen, and the rest percentage is water of crystallization. Calculate the molecular formula of the compound if its molecular mass is 283.
11.(a) (i) Name the compound which causes temporary hardness of water and the compound which causes permanent hardness of water.
(ii) Write one balanced chemical equation in each case to show how to remove temporary and permanent hardness of water.
(b) State four steps employed in the extraction of moderate reactive metals.
12.(a) Giving three reasons, explain why air is said to be a mixture of gases.
(b) (i) People suffering from heart burn usually use wood ashes for relief. Mention characteristic which makes the ashes to be used for heart burn relief.
(ii)Give four compounds found in laboratories which show the same characteristics as ashes.
SECTION C (15 Marks)
Answer one (1) question in this section.
13. Describe four common stages for the extraction of metals. Does the extraction of gold follow all four stages? Give reasons.
14. Read the following information carefully then answer questions that follow: 25 cm3 of potassium hydroxide were placed in a flask and a few drops of phenolphthalein indicator were added. Dilute hydrochloric acid was added until the indicator changed colour. It was found that 21 cm3 of acid were used.
(b) (i) What piece of apparatus should be used to measure out accurately 25 cm3 of sodium hydroxide solution?
(ii) What colour was the solution in the flask at the start of the titration?
(iii) What colour did it turn when the alkali had been neutralized?
(c) (i) Was the acid more concentrated or less concentrated than the alkali? Give reasons for your answer.
(ii) Name the salt formed in the neutralization.
(iii) Write an equation for the reaction.
(d) Utilizing the given information describe how you can obtain pure crystals of the salt.
FORM THREE CHEMISTRY EXAM SERIES 50
FORM THREE CHEMISTRY EXAM SERIES 50
THE PRESIDENT’S OFFICE
MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
SECONDARY EXAMINATION SERIES
CHEMISTRY 1 MID TERM EXAMINATION
FORM THREE-2021
Time: 3Hours
Instructions.
Atomic masses; H=1, C=12, N=14,O=16, Na=23, S,=32, Ca =40, Cl =35.5, Cu=64, Zn=65.
Avogadro’s number = 6.02 x 1023
GMV at s.t.p = 22.4dm3
1 faraday = 96,500 coulombs.
Standard temperature = 273K
Standard pressure = 760mmHg.
1 Litre = 1 dm3 = 1000cm3
SECTION A (20 Marks)
Answer All questions in this section.
1. For each of the items (i)-(xv), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.
LIST A | LIST B |
|
|
QN | I | II | III | IV | V |
ANSWER |
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|
SECTION C (70 MARKS)
Element | Atomic number | Atomic mass |
P | 8 | 16 |
Q | 9 | 19 |
R | 11 | 23 |
S | 6 | 12 |
T | 18 | 40 |
Questions:-
Element | P | Q | R | S | T |
Electronic configuration |
|
|
|
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|
______________________________________________________________________________________________________________________
(b) Write the chemical symbols for the following elements:-
(i) Magnesium________ (ii) Tin _______(iii) chromine_____ (iv) Lead______
(c ) For each of the following chemical symbols of elements write its corresponding chemical name:-
1 |
| 18 | ||||||
2 | 5 |
| 8 | 10 | 12 | 14 | 16 | 19 |
3 | 6 |
| 9 | 11 | 13 | 15 | 17 | 20 |
4 | 7 | Transitional elements |
|
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|
Questions:-
For each number write the chemical symbol of the corresponding element
Number | 1 | 2 | 4 | 6 | 8 | 11 | 12 | 17 |
Symbol |
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|
|
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|
Atomic number | Comment |
12 |
|
17 |
|
(b) 0.7g of nitrogen combines with 1.6g of oxygen to form a nitrogen oxide. Given the molecular mass of a compound is 92.
Calculate: (i) The empirical formula
(ii)The molecular formula
(Use atomic masses N= 14, O= 16).
(ii Write a chemical formula for water_______________
(b) (i) What is a fuel?_____________________________________________
(ii) Give two examples for each of the following categories of fuels in terms of their states of matter
Solid fuels_____________________________________________________
Liquid fuels_____________________________________________________
Gaseous fuels__________________________________________________
6. (a) Define the term a chemical equation.
(b) Write down components of a chemical equations list only three (3).
(c) Balancing the following chemical equations;
7. (a) Give the IUPAC names for each of the following compounds:-
(b) Calculate the oxidation number of underlined elements:-
(i) CO2- (ii) HCO3 (iii) KClO3
(c) Write the electronic configuration of Cl- and hence draw its electronic diagram.
8. Explain the meaning of each of the following types of chemical reactions and support your explanation with the help of a relevant chemical equation.
Sample | Volume of soap (cm3) used for water that was | ||
Untreated | Boiled | Passed through ion exchanger | |
A B C D | 12 17 26 1.6 | 1.8 17 20 1.6 | 1.8 1.7 1.8 1.6 |
Use the above results to answer the following questions;
10. (i) Define the following terms;
(ii) Explain why the ability of temporary hard water to conduct electricity falls when the water is boiled but does not fall when temporary hardness is removed by addition of washing soda.
11. Give a brief account to the following
(ii) Why is iron not usually recommended in the construction of steam pipes and boilers.
(ii) Write one balanced chemical equation which shows how temporary hardness can be removed by boiling. Also write one balanced equation which shows how sodium carbonate can be used to remove permanent hardness of water.
12. (a) Define the following words:-
(b) Give at least three (3) uses of salts
(c ) When zinc granules and dilute sulphuric acid are reacted together, gas M is produced. The gas produced is collected by downward displacement of water. Use this information to answer the questions below:-
SECTION C (15 Marks)
Answer one question in this section.
13. For each of the following write equations for the reactions that would take place.
14. (a) 416g of anhydrous barium chloride where obtained when 488g of hydrated salt were heated.
Calculate the value of n is the formula BaCl2.nH2O (Ba = 137)
(b) Give the meaning of the following;
(i) An acid
(ii) Molar solution of an acid
(iii) Give three characteristics of acid.
FORM THREE CHEMISTRY EXAM SERIES 49
FORM THREE CHEMISTRY EXAM SERIES 49
PRESIDENT'S OFFICE
REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT
ANNUAL EXAMINATION
CHEMISTRY F3- FORM THREE
NAME………………………………………..CLASS……………………………TIME: 3HRS
Instructions:
H = 1, C = 12, N = 14, O = 16, Na = 23, Pb = 207
Al = 27, Cu = 64, Ca = 40, Cl = 35.5, Mg = 24.
Avogadros number = 6.02 x 1023
GMU at stp = 22.4dm3
Faradays constant = 96500C
Standard pressure = 760 mm Hg
Standard temperature = 273K.
SECTION A (15 Marks)
Answer all questions in this section.
2FeCl2 + Cl2 2FeCl3
Chlorine may be regarded as;
LIST A | LIST B |
|
|
SECTION B (70 Marks)
Answer all questions in this section.
(b) Define the following terms;
(b) A solution of acetic acid (CH3COOH) was made by dissolving 3.00g of the acid in 0.5
dm3 of solution. Upon titration 12.00cm3 of this solution required 25.00cm3 of
sodium hydrogen carbonate for complete neutralization. Calculate the molarity of the
bicarbonate (NaHCO3).
The ratio of the reacting moles is 1:1.
(b)Write down three differences between potassium ions and potassium atom.
E. 2 : 8 : 8 : 2F = 2 : 8 : 6
(a)Which of the above elements would you expect to be;
(b)What would you expect to be the formula of the compound formed in each of the following pairs;
(c)Deduce the period and group in the periodic table of;
(i)E(ii) F
(d)Write down a balanced chemical equation showing what would happen if an oxide of element E was treated with dilute hydrochloric acid.
(b) Mention three methods of purifying domestic water.
(c) What causes the following;
i. Temporary hardness in water
ii. Permanent hardness in water
(d) i. With the aid of chemical equations explain why it is possible to soften temporary
hardness by boiling.
ii. Mention one advantages of using hard water.
(b) An element Z has a relative atomic mass of 88. When a current of 0.5 amperes was
passed through fused chloride of Z for 32 minutes and 10 seconds 0.44 of Z were
deposited at the cathode;
(b) Draw the energy – level diagram for exothermic reactions and Endothermic reactions.
(c) Name four (4) characteristics of good fuel.
(a)Write a balanced chemical equation for neutralization of metal hydroxide XOH.
(b) Calculate the concentration of metal XOH in mole per dm3.
(c)i. Calculate molar mass of XOH
ii. Identify element X.
ii. Define the term electrolyte.
(b) A bluish copper sulphate aqueous solution was electrolysed by using copper
electrodes.
(a) Define and point of titration
(b) What colour change indicate end point in the titration of a base against an acid on using (i) Methyl orange?(ii) Phenolphthalein?
(c) A teacher of chemistry provided his F3 students with the following:
AA – A solution of 0.12 0M HCl
BB – A solution of hydrated sodium carbonate, Na2CO3 containing 14.30g/dm3. On titration by using a 20cm3 pipette one of the best student obtained the following readings from a standard burette
Burette readings | Pilot | 1 | 2 | 3 | 4 |
Final volume (cm3) | 18.00 | 35.90 | 27.90 | 45.50 | 27.60 |
Initial volume (cm3) | 0.00 | 18.00 | 10.20 | 27.90 | 10.00 |
Volumeused (cm3) |
(i)Suggest the colour change at the end point
(ii)Suggest the indicator used by the student in the titration
(iii)Complete the table above
(iv)Calculate the average volume used for complete neutralization of the base by acid
(v)Find the value of X in the formula Na2CO3X H2O
12.(a) State three main physical properties of water and show the usefulness of each property.
(b)State three industrial application of electrolysis.
SECTION C (15 Marks)
Answer one (1) question from this section.
12. Explain how to handle chemicals having the warning signs of flammable, corrosive, harmful, explosive and toxic in the laboratory.
13. Explain six measures for minimizing the environmental degradation caused by extraction of metals in Tanzania.
FORM THREE CHEMISTRY EXAM SERIES 35
FORM THREE CHEMISTRY EXAM SERIES 35
THE PRESIDENT'S OFFICE
MINISTRY OF REGIONAL GOVERNMENT AND LOCAL GOVERNMENT
AUGUST-SEPTEMBER EXAMINATION SERIES
CHEMISTRY FORM-3
2020
TIME: 2:30 HRS
Instructions
Atomic masses: H 1, O- 16, N- 14, S = 32, Zn - 65, Cl -35.5, cu - 64.
Avogadros number= 6.02 x 1023
GMV at s.t.p =22.4 dm3 .
1 Faraday= 96,500 coulombs.
Standard pressure = 760 mm Hg. Standard temperature 273 K.
1 litre =1 dm3 =1000 cm 3.
SECTION A (15 Marks)
Answer all questions in this section.
1. For each of the items (i) — (x), choose the correct answer from among the given alternatives and write its letter beside the item number in the answer booklet provided.
(i) "Water is referred to as the universal solvent". What does this mean?
(ii) What is the proper set of apparatus would you use to grind granules of a solid substance into fine powder in the laboratory?
(iii) Which of the following sets of processes uses a gas that ignites with a "pop" sound when a lighted splint is passed through it?
(iv) A current of 0.2 A was passed through an electrolyte for 16 minutes and 40 seconds. What is the quantity of electricity produced in coulombs?
(v) Aluminium does not react with water and does not corrode much in air because
(vi) When a burning fuel produces blue color it means there is
(vii) Which of these can be reduced when heated with carbon?
(viii) Which of the following is NOT among the composition of air?
(ix) If a steady current of 2 amperes was passed through an aqueous solution of iron (II) sulphate for 15 minutes, the mass of iron deposited at the cathode will be.
(x) Two substances are allotropes of carbon if
2. Match the descriptions in List A with the corresponding scientific procedures in List B by writing the letter of the correct response besides the item number in the answer booklet provided.
LIST 1 | LIST B |
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SECTION B (70 Marks)
Answer all questions in this section.
3. (a) How many chlorine molecules are in 20 cm of chlorine gas at s.t.p?
(b)Calculate the number of ions present in 5 g of copper II nitrate.
4. (a) Distinguish temporary hardness from permanent hardness of water.
(b) With the help of chemical equations, explain how you can remove each type of water hardness in 5(a).
5. (a) Copper obtained from copper pyrites (CuFeS2) is impure for electrical wiring and has to be purified by electrolysis.
(i) Name the electrolyte and the electrodes used during electrolysis.
(ii) Write the observations that can be made during the electrolysis.
(b) The following flow diagram shows the stages in the contact process
(i) Give the names of element A, catalyst B and an acid C.
(ii) Write a balanced chemical equation for the formation of sulphur trioxide in stage 2
6. (a) Give one example in each of the following:
(i) Alkali earth metals.
(ii) Noblegases .
(iii) Transition elements.
(b) Write the names of the following processes of changing matter from one state to another.
(i) Gas to liquid.
(ii) Ga s to solid.
(iii) Solid t o gas .
7. (a) State four steps employed in the extraction of moderate reactive metals.
(b) Write balanced chemical equations to show how chlorine reacts with the following:
8. (a) State three main physical properties of water and show the usefulness of each property.
(b) State three industrial application of electrolysis.
9. (a)An atom M has an atomic number 14 and mass number 28.
(i)What is the number of protons and neutrons?
(ii) Write the electronic configuration of atom M.
(b) Calculate the volume of water which was produced when 1,120 cm3 of oxygen at s.t.p. was liberated during the decomposition of hydrogen peroxide. The density of water = 1.0 g/cm3
10. (a) Determine the empirical formula of a substance that has the following composition by mass; 49.5% oxygen.
(b) Give one reason why Alluminium is chosen to make each of the following items:
11. (a) Identify and state the environmental problem caused by the gas which is released from the blast furnace in the extraction of iron from its oxide.
(b) (i) Draw a labeled diagram of a simple electrolytic cell which show how copper is purified.
(ii) Write balanced ionic equations to show the electrode reactions which occur when copper is purified.
12. (a) (i) Why chemistry laboratory exits open outward?
(ii) State the uses of any four items found in a First Aid Kit.
(b) (i) Arrange the following metals in order of increasing reactivity; zinc, magnesium, calcium, copper and mercury.
(ii) Which one of the metals in (b) (i) above reacts with steam to form an oxide which is white when cold and yellow when hot?
SECTION C (15 Marks)
Answer one (1) question from this section.
13. In Tanzania, soil conservation is very important for Industrial Materials production. Explain six methods that are used to manage loss of plant nutrients from the soil.
14. 0.48g of a metal, M was placed in a test tube and hot copper (II) sulphate solution was added to it and stirred until the reaction stopped. The metal (M) displaced copper from copper (II) sulphate solution. Copper was filtered, washed with water, dried at 1000 C and the mass found to be 1.27g. Given that, the balanced chemical reaction that occurred is M (s) + CuSO 4(aq) MSO 4(aq) + Cu (s)
(a) Calculate;
(b) State the appearance of the metal formed (Cu).
(c) With ionic equations, explain why the reaction can be considered to involve both oxidation and reduction.
FORM THREE CHEMISTRY EXAM SERIES 24
FORM THREE CHEMISTRY EXAM SERIES 24
THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, LOCAL ADMINISTRATION AND LOCAL GOVERNMENT
CHEMISTRY- TERMINAL EXAMINATION-MAY
FORM THREE
TIME: 2HRS 2020
NAME:_______________________________________CLASS:___________
INSTRUCTIONS
H=1, N=14, O=16, C=12, Fe=56, Pb=207, Cl=35.5, Ca=40, Mn=55, K=39, 1litre=1dm3=1000cm3
Avogadro’s constant=6.02x1023 particles
1 faraday=96500 coulombs
GMV at STP=22.4dm3
SECTION A (20 MARKS)
1. For each item (i-x) choose the correct answer from given alternative and write it beside the item number in answer booklet provided.
(i) An element in periodic table with atom number 18 belongs to which of the following
(ii) The ionic equation when ammonium chloride react with sodium hydroxide is
(iii) The reason why white anhydrous copperII sulphate turns Blue when exposed to atmosphere is
(iv) Chemical change means
(v) If a stead current of 2 amperes was passed through an aqueous solution of ironII sulphate for 15 minutes, then, mass of iron deposited will be.
(vi) Which of the following solutions is the most concentrated?
(vii) Copper can be separated from mixture of zinc and copper by adding to the mixture
(viii) 10cm of 0.4M sodium hydroxide are added to 40cm3 of 0.2M Hcl. The resulting mixture will be
(ix) The only metal which does not react with dilute Hcl is
(x) During electrolysis of molten aluminum oxide; 3 faradays were needed to deposit one mole of aluminum. The number of electrons of aluminum will be:
2. Match the items in list A with responses in list B by writing the letter of correct response beside item number in separate answer sheet.
LIST A | LIST B |
(i) Its nitrate decomposes to metal, nitrogen dioxide and oxygen (ii) Its chloride is used as a drying agent (iii) Its carbonate is used to remove hardness of water (iv) It is stored paraffin (v) It hydride ion is metallic in nature (vi) Exists into two main physical forms (vii) Greenish- yellow gas (viii) Forms insoluble sulphate (ix) Reacts with carbon dioxide to form an oxide (x) Used as sacrificial element in catholic protection |
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SECTION B (54 MARKS)
3. a) Why do chemistry laboratory exits open outward?
State uses of any four items in first Aid Kit
b) i) Arrange the following metals in order of increasing reactivity – zinc, magnesium, calcium, copper, mercury
ii) Which of the following metals b (i) reacts with steam forming an oxide which is white when cold and yellow when hot?
4. a)20cm of solution containing 7g dm3 sodium hydroxide were exactly neutralized by 25cm of 0.1M Hcl. Calculate the concentration of sodium hydroxide in moles per dm
b) Give two examples of
(i) Gaseous solution
(ii) Solid solution
5. a)The table below show part of periodic table study it and answer questions that follow
H |
| He | |||||
Li | Be | B |
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| F |
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| Al | Si | P | S | Cl | Ar |
Fill all missing elements
(i) Write the reaction equation involved in industrial manufacture of sulphuric acid in contact process; starting with sulphur metal
(ii) Explain why sulphur trioxide is not dissolved directly in water to obtain sulphuric acid
6. a)Explain how you can separate crystals of copper II sulphate from pieces of broken glasses
b) With aid of equation explain how washing soda removes hardness of water
7. Table below give information about composition of three samples of water Mineral content per Mg per litre
Ions | Kahama | Maswa | Bukombe |
Ca2+ | 28 | 82 | 18 |
Mg2+ | 14 | 41 | 13 |
Cl- | 53 | 7 | 22 |
Na+ | 7 | 143 | 39 |
HCO-3 | 281 | 5 | 93 |
SO42- | 2 | 14 | 16 |
(i) State two ways in which these ions get into water
(ii) Give two reasons, state hardest water sample
(iii) State two ways that can be used to remove hardness in (II)
b) Write the following molecular equation to ionic
(i) Fe(s) + CUSO4(aq) → FeSO4(aq) + Cu(s)
(ii) Na2SO4(aq) + Bacl2(aq) → BaSO4(g) + 2Nacl(aq)
State the type of chemical reaction
(8) a) When a burning splint is introduced in gas for containing CO2, the flame goes off.
i) What two properties of CO2 does this experiment lustrate?
ii) What type of equipment widely used in everyday life makes use of these two properties?
b) The equation below show dissociation of calcium carbonate
CaCO3(s) → CaO(s) + CO2(g) H
(i) Is the forward reaction endothermic or exothermic?
(ii) What factors favour forward reaction?
(iii) What will be the effect on proportion of CaCO3 in the equilibrium mixture if temperature is decreased?
9. a)Lead nitrate decompose on heating as follows
2 Pb (NO3)2(g) → 2PbO(S) + 4NO2 (g) + O2(g)
112dm3 of O2 were collected at STP when a sample of a lead nitrate was completely decomposed on heating. Calculate mass of load II nitrate in the sample.
b) Define the following terms
(i) Mole
(ii) Titrant
(iii) Analyte
(iv) Molar solution
10. a)Differentiate between
(i) A base and alkali
(ii) Atom and isotope
b) An organic compound P consists of 52.2% carbon, 13% hydrogen, and 34.8% oxygen.
The vapour density of P is 23. Calculate the molecular formula of compound P
11. Describe the extraction of iron using the blast furnace
SECTION C (26 MARKS)
12. Assume that you are a chemist in a chemical plant and want to produce 100litres of chlorine gas per hour so as to reach company goal of producing 2400litres every day. What current of electricity will you allow to flow per hour?
13. A solution of hydrated sodium carbonate was nitrated with 1.68M nitric acid solution. 30cm3 of the solution required 28.75cm3 of nitric acid for complete reaction. If the solution was prepared by dissolving 12.056g of the carbonate to make 600cm3 of solution, determine the molecules of water of crystallization in hydrated sodium carbonate.
END
FORM THREE CHEMISTRY EXAM SERIES 13
FORM THREE CHEMISTRY EXAM SERIES 13
THE PRESIDENT’S OFFICE
MINISTRY OF EDUCATION AND LOCAL GOVERNMENT
MID TERM EXAMINATION-MARCH 2020
CHEMISTRY FORM THREE
NAME………………………………….………………..CLASS…………………………….……………TIME: 3HRS
INSTRUCTIONS:-
1.This paper consists of sections A,B and C
2.Answer all questions in all sections
3.Whenever necessary, the following constructs may be used.
SECTION A (15 marks)
LIST A | LIST B |
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SECTION B (70 marks)
(b) Write down the names and formulae of three common acids in the laboratory.
(c ) What is an indicator? Give four (4) examples of acid- base indicators.
(d) Write down the products formed when each of following pairs of compounds react:
(i) Acid and metal
(ii) Acid and metal carbonate
(b) Write a balanced chemical equation and its corresponding ionic equation for the reaction between dilute sulphuric acid and:-
N.B. show all the state symbols.
(b) Calculate the molar mass of (i) Al2 (SO4)3 (ii) Na2 CO3 10H2O
( c) State the Avogadro’s law
(d) How many oxygen molecules are there in 20cm3 of oxygen gas at STP?
(ii) Name two types of flames produced by the Bunsen burner
(iii)How do the two above mentioned flames differ?
(b) Write down four (4) careers that are a result of studying chemistry.
(ii) Does Oxygen burn? Why?
(ii) Explain the meaning of catalyst.
(iii)How can you test for oxygen?
Note: The letters used are not the scientific symbols for the elements concerned.
I O | |||||||
| II | III | IV | V | VI | VII |
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| N |
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| K |
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| Q |
| P |
L |
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9. (a) Write the chemical symbols for beryllium, boron, neon, nitrogen and phosphorus.
(b) Why some of the elements in 9(a) are assigned symbols with only one letter while others bear symbols with two letters?
10. (a) Give three advantages of using chemical equations over word equations.
(b) You are provided with a compound composed of 22.2% zinc, 11.6% sulphur, 22.3% oxygen, and the rest percentage is water of crystallization. Calculate the molecular formula of the compound if its molecular mass is 283
11. (a) Which ways are the fossil fuels detrimental to the environment? Give four points.
(b) Briefly explain how biogas is produced by using domestic waste.
12. (a) Write the IUPAC names of the following compounds
(b) Write the chemical formula of the following compounds
(i) Lead (II) chloride
(ii) Aluminium hydride
(iii) Sodium hydrogen phosphate (v)
(iv) Sulphur oxide (VI)
(v) Ammonium chloride
SECTION C (15 Marks)
Answer one (1) question from this section.
13. (a) Differentiate between basic salt and acidic salt.
(b) Categorize the following salts;
i. PbSO4 ii. MgHSO4 iii. Zn(OH)Cl iv. MgHCO3
v. NH4HSO4 vi. Ba(NO3)2
Salts | Category |
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(c) 1.16g of magnesium was allowed to react with excess dilute sulphuric acid. What
volume of Hydrogen gas at STP was liberated.
14. (a) Define the following;
(b) On titration 20cm3 of a solution containing 2.65g per 500cm3 of A2CO3, exactly
react with 20cm3 of 0.1M hydrochloric acid solution. Write balanced equation;
FORM THREE CHEMISTRY EXAM SERIES 3
FORM THREE CHEMISTRY EXAM SERIES 3