THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATION COUNCIL
CHEMISTRY FTNA 2018
(i) Chemistry is a branch of Science which deals with:
(ii) Which of the following are the states of matter?
(iii)Which of the following are the main components of a fire triangle?
(iv)The process of removing solid contaminants from water is known as:
(v)How many zones are there in a non-luminous flame?
(vi)The process of coating iron or steel with zinc is known as:
(vii)A certain element has atomic number W and mass number Y. The number of neutrons contained in its nucleus is:
(viii)When a small amount of sugar is dissolved in a glass of water the mixture formed is:
(ix)Fainting is a sudden loss of:
(x)Why is fractional distillation of coal done?
2. (a) Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided.
LIST A | LIST B |
(i)It occurs between two ions with opposite charges. (ii)It involves the sharing of electrons between atoms. (iii)Shows the simplest ratio of atoms or ions in a compound. (iv)Shows the actual number of each atom in a molecule. (v)A force of attraction that holds atoms together to form molecules. |
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(b) Fill in the blank spaces with the correct answer.
(i)A reaction that releases energy in the form of light and heat is called..........
(ii)A chemical process that occurs in steel and iron in the presence of air and water is known as..........
(iii)Oxygen, heat and fuel ar the three components that make..........
(iv)Injuries that result from the body coming into contact with heat of harmful chemicals are called..........
(v)A solution which can dissolve no more solute at a given temperature is called .
SECTION B
3. (a) Indicate the corresponding meaning of the following warning signs.
| Symbol | MEANING |
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iii |
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iv |
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(b) Give four importance of First Aid.
4. Draw and give one function of the following apparatus:
Aparatus | Drawing | Function |
(i) Measuring cylinder | | |
(ii) Conical flask | | |
(b) By excluding a Bunsen burner, mention other three sources of heat that can be used in the laboratory.
(c) Why is a Bunsen burner the best heat source in the laboratory? Give three (3) reasons.
5. Define the following terms:
(i)Brownian motion
(ii)Compound
(b) Identify whether the following is a physical or chemical change:
(i) Cutting aluminium foil into pieces
(ii) Lighting a match .
(c) How can you separate the following mixtures? Briefly explain.
(i)Water and kerosene
(ii)Salt and water
(iii)Ethanol and water
6. During preparation of Hydrogen gas by the reaction between dilute Hydrochloric acid and Zinc granules, the granules slowly dissolve in acid to form solution X.
(i) Name solution X .........
(ii) Write the chemical formula of X
(b)How can hydrogen gas be tested?
(c)Mention four (4) chemical properties of hydrogen gas.
(d)List three (3) uses of Hydrogen gas.
7. (a) (i) How many electrons and protons are present in oxygen element
and aluminium element?
(ii) Write the electronic configuration of chlorine ion.
(b) Use the elements with chemical symbols: P, S and Cl to answer the following questions:
(i)Which elements is the most electronegative?
(ii)Mention the least electronegative element.
(iii)Which element has the largest atomic structure?
(c) Study the following table with elements lettered F, G, L, M and J, then answer the question that follows
Element | Atomic Mass | Atomic Number |
F | 16 | 8 |
G | 19 | 9 |
L | 23 | 11 |
M | 12 | 6 |
J | 20 | 10 |
(i)How many neutrons are present in element L?
(ii)Which group and period of the periodic table does element F belong?
(iii)Which element does not readily form compounds? Give a reason.
8. Write four (4) sources of energy used for cooking in most Tanzanian societies.
(b) List four (4) characteristics of a good fuel.
(c) List two areas where scientific procedure can be applied.
9. Outline six common apparatus used in the laboratory preparation of oxygen gas using hydrogen peroxide.
(b) Outline four uses of oxygen in everyday life situation.
10. (a) Define the following terms:
(i)Valency
(ii)Oxidation state
(iii) Anion
(iv)Cation
(b) Calculate the oxidation state of the underlined elements in the following radicals:
(i) NH4+
(ii) SO42
(iii) ClO3
(c) A compound consists of 40% carbon, 6.67% hydrogen and 53.33% oxygen. If its relative molecular mass is 60, calculate the following:
(i)Empirical formula
(ii)Molecular formula
(i) Which statement gives a clear meaning of Chemistry?
(ii) The mass number of an atom is determined by:
(iii)Which of the following is a metal?
(iv)Air entering the Bunsen burner barrel can be controlled by
(v) How many atoms are there in a water molecule
(vi)Which neutral atom has the same number of eletrons as Mg2+?
(vii) The appropriate extinguisher used to put off fire caused by cooking oil is:
(vii) The appropriate extinguisher used to put off fire caused by cooking oil is:
(viii) A non-luminous flame is obtained if the hole is:
(ix)Which is the least abundant gas in the air?
(x) The process which produces energy in form of heat and light is called:
2. (a) Match each items in List A with a correct response in List B by writing
its letter below the number of the corresponding item in the table provided:
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(b) Fill in the blanks with the correct answer
(i) A flame is a zone of burning gas that produces ..................
(ii) The arrangement of electrons in different shells in the atom is
called ..................
(iii)A type of gas fuel derived from decomposing biological waste is called ..................
(iv) The three components of the fire triangle are heat fuel and
(v) A substance that speeds up a chemical reaction but remains chemically unchanged is called ..................
3. (a) Draw and state one function of each of the following apparatuses: (i) Burette
(ii) Filter funnel
(iii) Beaker
(b) Define the following terms:
(i) First aid
(ii) Laboratory
(c) List two components of a first aid kit.
4. Define matter.
(b) Tell whether the following is a chemical change or physical change.
(i) Rotting of mango.
(ii) Clouds changing into rain. (iii) Decaying of teeth.
(c) State four differences between a chemical change and physical change
5. Write the names and formulae of the two chemicals that can be used in the preparation of oxygen gas.
(b) (i) State an appropriate method of collecting oxygen gas based on solubility and density of the gas in water. (ii) How can oxygen gas be tested?
(c) List four uses of oxygen gas.
6. (a) Write the names of the following radicals:
(i)
(ii) C103
(iii) poi-
(b) Calculate the oxidation state of the underlined element in the following compounds:
(i) NH4Cl
(ii) A1203
(iii)Na2S04
(iv) H202
(c) Calculate the percentage composition by mass of the underlined element in the following compounds:
7. (a) (i) Why may a flame produced by a "spirit lamp" not be good for heating in the laboratory? Give two reasons.
(ii) Name the type of flame produced by a spirit lamp.
(b) By using locally available materials in your school, state how the fire can be extinguished in the following situations:
(i) Kerosene spilled on the floor catches fire.
(ii) Friends clothes catch fire which gets out of her control.
(c) Suggest the suitable method of preventing rust in the following:
(i) Moving parts of machines e.g. motorcycle chain. (ii) Motor vehicle (car) bodies.
8. The following is a part of periodic table with some elements represented by letters. Study it and answer the questions that follow.
Vlll
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C |
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E |
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| F | G |
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(a) (i) Mention the names of the elements represented by the following letters A to H
(ii) Write the electronic configuration of the elements represented by letters G and H.
(b) (i)Identify the letters which represent the elements with the following properties: (i) Zero valency
(ii) Lightest atom ..... ........
(iii)Alkaline earth metal .............
9. Hydrogen gas is prepared in the laboratory by reacting dilute hydrochloric acid and zinc granules.
(a)Write an alternative acid that can be used to prepare hydrogen instead of dilute hydrochloric/acid.
(b) Given two physical and two chemical properties of hydrogen.
(c)What will happen if a burning wooden splint is lowered in a test tube containing hydrogen gas?
(d) Give two uses of hydrogen gas in daily life.
10. The following figure shows the apparatus that can be used to separate three liquids: cooking oil, kerosene and water with density 0.92g/cm3 and 1.00g/cm3 respectively.
(i) Name the apparatus shown by the given figure (ii) By giving a reason, identify liquids A and C
Liquid A .............
Liquid C
Reason .............
(b) The following table shows the name and the chemical formula of the product formed when ions combine together. Complete filling the table Table showing combination of ions
ions | Name | Formula | |
Ca2+ |
| Calcium chloride |
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Al3+ | so42- |
| Al(SO4)3 |
H+ |
| Hydrogen sulphate |
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(i) Chemistry is defined as:
(ii) A non-luminous flame is the most applicable flame for heating purposes because:
(iii) Matter is defined as anything that has:
(iv) Which of the following process is used in preventing rust of an iron?
(v) Water is a universal solvent because:
(vi) Carbon has two main isotopes, 12 C and 14 C with relative abundance of 98.89% and 1.11% respectively. Calculate the relative atomic mass of carbon.
(vii) Class F fire can best be extinguished by using
(viii)Which of the following components can be separated by filtration method?
(ix) Which of the following is the colour change when cobalt chloride paper is used to test the presence of water?
(x) All domestic utensils made of iron undergo rusting when exposed to
SECTION B
2. Match each item in List A with a correct response in List B by writing its letter bellow the number of the corresponding item in the table provided
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3. Write the name and chemical formula of two important chemical substances used in the laboratory preparation of oxygen gas. (b) Mention four physical properties of oxygen gas.
4. Write four sources of energy used for cooking in Tanzania (b) What are the four characteristics of a good fuel?
5. What are the five steps used in lighting a Bunsen burner?
(b) Classify fuels based on their physical state and for each class give two examples.
6. Explain three factors which affect the problem being investigated (b) Explain two areas where scientific procedure is applied.
7. (a) Differentiate metals from non metals
(b) Classify each of the following elements into their respective groups and periods.
(i) Berylium
(ii) Magnesium .. .................................
(iii) Neon
(iv) Potassium „............. ................... ....
(v) Chlorine
8. Explain each of the following terms:
(i) Burn
(ii) Bruises
(iii) Fainting ..............................................
(b) What are the six procedures which can be used to help a person with severe bleeding on the wound?
9. The following figure shows a set-up used to prepare gas
Water |
(a) Identify gas Q
(b) Identify other two chemical substances that could be used in the laboratory to prepare gas Q if zinc is not present. (c) State two physical properties of gas Q.
(d) State two chemical properties of gas Q.
10. (a) The diagram below shows the bonding between two elements A and B.
(i) Write the valence of B.
(ii) Identify the valence of A.
(iii) State the type of bonding formed between A and B.
(iv) Write the formula of the compound formed by A and B.
(b) Write the formula of the compound formed by the combination of:
(i) NH4+ and SO 2-
(c) State the number of atoms of each element in CaClz.
(d) Calculate the oxidation state of sulphur in SO 2-.
(i) Which of the following is the most correct statement about hypothesis?
(ii) Which of the following is not among the gases composing air?
(iii) When an atom loses or gains electron, it becomes:
(iv) A change from gaseous state to solid state without passing through a liquid state is called:
(v) What is the type of a fire associated with electrical equipment?
(vi) Which among the following are the two processes involved during distillation?
(vii) Which of the following set of nuclide notation represents isotopes?
(viii) The chemical used to test the presence of water in a substance is:
(ix) When a burning fuel produces blue colour it means there is:
(x) Which of the following is the best apparatus for measuring accurately a fixed volume of a given solution?
2. Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided.
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Group of elements which react quickly with water to form alkaline solution. The ability of an atom to attract an electron. (iii) Group of elements in which their shells are completely filled up. (iv) A vertical column of elements in the periodic table. (v) Group element which react slowly with water to form alkaline solution. Group of elements which react with metals to form salts. (vii) Group of elements which react by receiving electrons. (viii)The systematic arrangement of elements according to their increase in atomic numbers. (ix) Group of elements with high densities and melting points, and often act as catalysts. (x) Group of elements which have both metallic and non-metallic characteristics. | A. Metalloids B. Non-metals C. Periodicity D. T r a n s i t i o n elements E. Electronegativity F. Alkali metals G. Halogens H. Periodic law I. Alkali earth metals J. Rare non metals K. Period L. Noble gases M. Periodic table N. Group | |
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3. (a) Define the following terms:
(i) Oxidation state
(ii) An element .......„
(iii) A compound
(iv) Fainting
(b) Write the chemical formula for each of the following compounds:
(i) Sodium sulphate
(ii) Sodium chloride ..
(iii) Calcium nitrate .........
(iv) Calcium oxide .
4. Gas X can be prepared in the laboratory by the decomposition of hydrogen peroxide.
(a) Identify gas X ..
(b) State three physical properties of Gas
Mention three chemical properties of gas X. (d) State three uses of gas X.
5. Write the name of each of the following compounds:
(i) (NH4)2C03
(ii) caC12
(iii)
(iv) KC103
(b) Give three differences between the following:
(i) Electrovalent compounds and covalent compounds. (ii) Solutions and suspensions.
6. State two chemical properties of water.
Calculate the molar mass of each of the following compounds:
(ii) NaHC03 (iii) Fe203
(c) State whether each of the following is a chemical or physical change:
(i) Burning of charcoal .........
(i) Rusting of iron sheets
7. (a) Study the following Periodic Table and then answer the questions that follow.
I VIII
A | II iii | IV V VI VII | B | ||||
| C |
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F | G |
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| H |
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(i) Write the collective name of elements in:
Group Il .. Group VIII
(ii) Name the elements which are represented by the following letters:
(iii) Write the electronic configuration of the following elements:
(b) Name two products in each of the following fields made by the application of chemistry.
(a) Medicine
(b) Food and be average industry
8. (a) Calculate the oxidation number of the underlined elements:
(i) K2C2O4 (II) SO32-
(b) What is the use of each of the following apparatus? (i) Thistle funnel (ii) Pipette .........
(iii) Wire gauze ......... (iv) Burette .........
9. When dilute hydrochloric acid is reacted with zinc metal, gas Z is formed.
(a) Identify the name of gas Z.
(b) Mention four physical properties of gas Z. State two uses of gas Z.
10. Define the following terms:
(i) Empirical formula .........
(ii) Molecular formula .........
(b) A compound consists of 85.7% carbon and 14.3% hydrogen by mass. If its relative molecular mass is 56, calculate:
(i) Empirical formula.
(ii) Molecular formula.
(i) Which of the following is the most correct statement about hypothesis?
(ii) Which of the following is not among the gases composing air?
(iii) When an atom loses or gains electron, it becomes:
(iv) A change from gaseous state to solid state without passing through a liquid state is called:
(v) What is the type of a fire associated with electrical equipment?
(vi) Which among the following are the two processes involved during distillation?
(vii) Which of the following set of nuclide notation represents isotopes?
(viii) The chemical used to test the presence of water in a substance is:
(ix) When a burning fuel produces blue colour it means there is:
(x) Which of the following is the best apparatus for measuring accurately a fixed volume of a given solution?
2. Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided.
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Group of elements which react quickly with water to form alkaline solution. The ability of an atom to attract an electron. (iii) Group of elements in which their shells are completely filled up. (iv) A vertical column of elements in the periodic table. (v) Group element which react slowly with water to form alkaline solution. Group of elements which react with metals to form salts. (vii) Group of elements which react by receiving electrons. (viii)The systematic arrangement of elements according to their increase in atomic numbers. (ix) Group of elements with high densities and melting points, and often act as catalysts. (x) Group of elements which have both metallic and non-metallic characteristics. | A. Metalloids B. Non-metals C. Periodicity D. T r a n s i t i o n elements E. Electronegativity F. Alkali metals G. Halogens H. Periodic law I. Alkali earth metals J. Rare non metals K. Period L. Noble gases M. Periodic table N. Group | |
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3. (a) Define the following terms:
(i) Oxidation state
(ii) An element .......„
(iii) A compound
(iv) Fainting
(b) Write the chemical formula for each of the following compounds:
(i) Sodium sulphate
(ii) Sodium chloride ..
(iii) Calcium nitrate .........
(iv) Calcium oxide .
4. Gas X can be prepared in the laboratory by the decomposition of hydrogen peroxide.
(a) Identify gas X ..
(b) State three physical properties of Gas
Mention three chemical properties of gas X. (d) State three uses of gas X.
5. Write the name of each of the following compounds:
(i) (NH4)2C03
(ii) caC12
(iii)
(iv) KC103
(b) Give three differences between the following:
(i) Electrovalent compounds and covalent compounds. (ii) Solutions and suspensions.
6. State two chemical properties of water.
Calculate the molar mass of each of the following compounds:
(ii) NaHC03 (iii) Fe203
(c) State whether each of the following is a chemical or physical change:
(i) Burning of charcoal .........
(i) Rusting of iron sheets
7. (a) Study the following Periodic Table and then answer the questions that follow.
I VIII
A | II iii | IV V VI VII | B | ||||
| C |
| D |
| E |
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F | G |
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| H |
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(i) Write the collective name of elements in:
Group Il .. Group VIII
(ii) Name the elements which are represented by the following letters:
(iii) Write the electronic configuration of the following elements:
(b) Name two products in each of the following fields made by the application of chemistry.
(a) Medicine
(b) Food and be average industry
8. (a) Calculate the oxidation number of the underlined elements:
(i) K2C2O4 (II) SO32-
(b) What is the use of each of the following apparatus? (i) Thistle funnel (ii) Pipette .........
(iii) Wire gauze ......... (iv) Burette .........
9. When dilute hydrochloric acid is reacted with zinc metal, gas Z is formed.
(a) Identify the name of gas Z.
(b) Mention four physical properties of gas Z. State two uses of gas Z.
10. Define the following terms:
(i) Empirical formula .........
(ii) Molecular formula .........
(b) A compound consists of 85.7% carbon and 14.3% hydrogen by mass. If its relative molecular mass is 56, calculate:
(i) Empirical formula.
(ii) Molecular formula.
(i) An isotope of carbon has an atomic number 6 and a mass number of 14, this means that it has:
(ii) Which of the following gives the correct meaning of air?
(iii) Why is water a universal solvent?
(iv) How many numbers of shells are there in Magnesium atom?
(v) Technicians prefer to use blue flame in welding because:
(vi) Which of the following is the characteristic of solid?
(vii) What is the oxidation state of Chlorine in KCIO3?
(viii) Which of the following is a sequential method of separating mixture of salt and sand?
(ix) Which of the following is the best apparatus for measuring accurately the volume of a given solution?
(x) The factors that affect the problem being investigated are referred to as:
2. Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided.
LIST A | LIST B |
(i) Method of recovery of both solute and solvent from a liquid. (ii) Method of separating two miscible liquids which their boiling points are close together. (iii) Method of separating two immiscible liquids. (iv) Method of separating two solids by heating in a way that one changes its state directly to gas. (v) Method of separating coloured components using a moving solvent on materials that absorb such solvent. (vi) A suitable method of separating edible oils from seeds. (vii) Method of separating solid mixture which contains iron. (viii)Method of separating an insoluble solid from a liquid. (ix) Method of separating a soluble solid and a solvent. (x) Method of separating liquids which forms a suspension with a solvent | A. Layer separation B. Chromatography C. Simple distillation D. Condensation E. Hand picking F. Fractional distillation G. Sieving H. Solvent extraction I. Evaporation J. Sublimation K. Magnetisation L. Magnetism M. Deposition N. Decantation O. Filtration |
3. (a) Define the following terms:
(i) Emulsions
(ii) A solution
(iii) Atom
(iv) Radical
(b) Write the chemical formula for each of the following compounds:
(i) Sodium sulphide
(ii) Beryllium chloride
(iii) Copper (I) oxide
(iv) Potassium oxide
4. Draw a diagram to show laboratory preparation of oxygen using hydrogen peroxide. In the diagram, label all the compounds and elements involved in the preparation.
Briefly explain how you would distinguish ordinary air from pure oxygen.
(c) List two chemical properties of oxygen gas.
5. Write the name of each of the following compounds:
(i) Cuo (ii) PC13 (iii) N204
(b) Give three differences between the following:
(i) Physical changes and chemical changes
(ii) Mixture and compounds
6. Give four physical properties of water
Calculate the molar mass of each of the following compounds: (i) Na3P04
(iii) caC03
7. (a) Study the following periodic table and then answer the questions that follow:
1 V111
| 11 111 IV | V | VI | Vll |
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| s |
| T |
| U | V |
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w |
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z |
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(i) Name and write the chemical symbols for the elements represented by the following letters: S,Z,W,X
(ii) Write the electronic configuration for the elements represented by the following letter.T, U, V, Y
(b) Name two products in each of the following fields made by the application of chemistry.
Field | Products |
(i) Home care and cosmetics |
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(ii) Transport |
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8. (a) Calculate the oxidation number of the underlined elements:
(i) HSO-3; (ii) N02-
(b) What is the use of each of the following apparatuses?
(i) Tongs . (ii) Spatula.........
(iii) Pipette......... (iv) Crucible .........
9. (a) Study the experiment diagram below and answer the questions that follow.
(i) What happens to the copper (II) oxide during the experiment?
(ii) What happens to the two pieces of cobalt paper? (iii) Write a word equation for the reaction.
(b) Mention four chemical properties of hydrogen gas.
10. (a) Define the following terms:
(i) Covalent bond
(ii) Electrovalent bond
(b) A compound consists of 82.8% carbon and 17.2% hydrogen by mass The vapour density of the compound is 29. Calculate:
(i) Empirical formula.
(ii) Molecular formula.
(i) The apparatus used for grinding granular chemicals in the laboratory include:
(ii) The substances that can be used to extinguish fire are:
(iii) Which of the following electronic configurations are of metals?
A. 2:8:1 and 2:5
B. 2:8:2 and 2:6
C. 2:8:3 and 2:8:8:7
D. 2:8:6 and 2:8:8:7
(iv) When sugar is dissolved in water, a uniform mixture is formed. The resulting mixture is called a:
(v) Flammable chemicals are those which:
(vi) Which of the following can be classified as a renewable source of energy?
(vii) The part of Bunsen burner that controls the amount of air coming in is called:
(vii) The part of Bunsen burner that controls the amount of air coming in is called:
(ix) The simplest formula of a compound formed when combining 13g of aluminum and 17g of chlorine is:
(x) The second step in the scientific procedure is:
SECTION B
2. Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided.
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SECTION C
3. (a) What do you understand by the following terms?
(i) Empirical formula .
(ii) Relative atomic mass .........
(b) A certain compound K contains 15.8% carbon and 84.2% sulphur. The molar mass of K is 76g/mol. Determine its:
(i) simplest formula ... ......
(ii) molecular formula .........
4. (a) Define the following terms as applied in Chemistry:
(i) Flame
(ii) Bunsen burner
(iii) Laboratory
(b) List four properties of each of the following:
(i) A luminous flame
(ii) A non-luminous flame
(c) Write the chemical formula for each of the following compounds:
(i) Sodium carbonate
(ii) Calcium nitrate
(iii) Ammonium chloride
5. (a) Calculate the percentage by composition of the underlined elements in the following compounds: (i) Na2S04
(ii) Ca(HCO3)2
(b) Give the use of each of the following components which are found in the First Aid kit:
(i) Plaster .........
(ii) A pair of scissors (iii) Cotton wool ......... (iv) Gloves .........
(c) Categorize the following changes as either chemical or physical:
(i) Freezing of juice in a bottle .........
(ii) Rusting of iron .........
(iii) Burning of wood .
(iv) Drying of wet clothes .........
6. (a) Define the following terms:
(i) Chemistry
(ii) Element
(iii) Catalyst
(b) Give three differences between the following:
(i) Compound and mixture
(ii) Suspension and solution
7. (a) The figure below shows the relationship among three states of matter. Name the processes involved in A, B, C and D.
(b) State the valency of each of the following atoms:
(i) Aluminium (ii) Neon
(iii) Sulphur (iv) Potassium
(c) Give the chemical formula for the combination of the following sets of ions:
(i) Mg2+, PO3-4
(ii) Fe3+, SO42-
8. (a) Write a word equation for each of the following reactions:
(i) Calcium burns in Oxygen .........
(ii) Sodium reacts with water ... ... ...
(b) What do you understand by the following terms?
(i) Water treatment
(ii) Water purification
(c) Mention six uses of water in economic activities.
9. Gas "L" has the following properties: it is highly flammable, readily combines with other elements, readily reacts with other chemical substances and is a strong reducing agent.
Name the gas L
(b) What is the method used to collect gas in the laboratory? Give a reason.
Give four uses of gas L
10. Mention four chemical properties of Oxygen.
(b) Find the oxidation number of each of the underlined elements in the following: (i) KC103
(ii)
(c) Use the IUPAC system to name each of the following chemical compounds:
(i) CuO (ii) CaSO4
(iii) HN03 (iv) ZnC12
(i) All domestic utensils made of iron undergo rusting when exposed to:
(ii) When a small amount of common salt is dissolved in a glass of water the mixture formed is:
(iii) A chemist should acquire all of the following skills except:
(vi) An important property of oxygen which distinguishes it from other gases is that it:
(v) The process of chlorination in water treatment aims at:
(vi) One of the following is not correct about coke being a better fuel than coal as it:
(vii) Class E fire can best be extinguished by using:
(viii) The following is a set of apparatuses which are used for heating:
(ix) Which of the following methods can be used to get oil from cotton seeds?
(x) Which of the following apparatuses is suitable for measuring volumes of smaller quantities of liquids?
2. Match each item in List A with a response in List B by writing its letter below the number of the corresponding item in the table provided.
LIST A | LIST B |
(i) A method used to separate mixtures of two or more liquids that form homogeneous solution by means of fractional column. (ii) A substance that absorbs moisture from the atmosphere and dissolves in it. (iii) Elements with stable structure. (iv) Molecular mass of calcium carbonate. (v) Poisonous gases prepared in it. (vi) Produces a "pop" sound. (vii) Quiet and unsteady flame. (viii) Smokeless solid fuel. (ix) Source of energy derived from animal waste, (x) Used to prevent direct heat to reach the apparatus. | A. Biogas B. Chromatograph C. Coke D. Corrosive E. Deliquescent F. Fractional distillation G. Fume chamber H. Hydrogen I. Luminous flame J. Noble gases K. Non-luminous flame L. Oxygen M. Wire gauze N. 80g/mol O. 100g/mol. |
3. (a) Mariam was preparing food for her family using hot oil in a frying pan. Accidentally the pan tripped over and a huge fire spread over her kitchen floor.
(i) Mention two extinguishers which would be appropriate for putting out the fire.
(ii) Which fire extinguisher would be dangerous to use when trying to put out the fire in (a) above? Give reason. (b) Mention three conditions for a fire to start.
(c) (i) What is combustion?
(ii) Give three areas where combustion is applied.
4. (a) In an experiment, two iron nails A and B were used whereby painting was applied on nail A. The two nails were placed in a moist environment and after one month the weight of each nail was determined. Which of the two nails would be heavier? Give reason.
(b) State the method which will be used to protect each of the following from rusting:
(i) Covering iron sheets with a layer of most reactive metals (ii) Bicycle chain
(c) Find the oxidation number of the underlined elements in the following:
(i) Mn04
(i) K2Cr07
5. Use the details given below about elements P, Q, R, S and T to answer questions (a) and (b).
(a) (i) Write down the electronic configuration of the elements represented by letters from P to T:
(i) How many neutrons are present in element Q? .
(c) Name the type of bonds that will be formed in the combination between the following elements:
(i) Q and T
(ii) S and T
(d) Write the chemical symbol for each of the following elements:
(i) Silver
(ii) Lead .........
(iii) Manganese .........
6. (a) Explain why petroleum and coal are non-renewable resources of energy. (b) What is fuel?
(c) The problem facing Tanzania society is misuse of charcoal and firewood as a source of fuel. Give two points of advice to the society on how to use less charcoal and firewood efficiently.
(d) Mention three categories of fuel and give two examples in each category.
7. (a) List down four careers that are a result of studying Chemistry.
(b) The following are possible causes of accidents which can occur in the Chemistry laboratory. State how you can avoid them.
(i) Poisonous chemicals left in an unlocked cupboard .........
(ii) A student picking up a bottle containing concentrated H2S04 acid by the neck .........
(iii) Concentrated acids stored in the upper most shelf of cupboard
8. An experiment showed that 13.88g of calcium chloride were obtained from the combination of 5g of calcium with unknown relative mass of chlorine.
(i) What is the simplest formula of calcium chloride .
(ii) What kind of bond exists between calcium and chlorine?
(iii) Give two properties of the bond you have mentioned in (ii) above.
(b) Define the following terms as applied in Chemistry
(i) Decantation
(ii) Filtration
(iii) Picking
(iv) Funnel Separation
(c) (i)Which is the most abundant element on the earths outer crust? (ii) The term used for acidic chemicals which can burn your skin is
(iii) Give the name of a flame which forms soot .........
9. (a) Explain why:
(i) a magnesium ion has a charge of 2+ .........
(ii) a magnesium oxide has no overall charge ..
(b) Give the name of a bond which can be formed between two oxygen atoms .......
(c) (i) State the modern periodic law
(ii) Give the special name for each of the following groups of elements in the periodic table:
Group I .........
Group Vll .........
(iii) Why is the atomic number a better way of identifying an element than the mass number? .
10. (a) Mention four physical properties of water.
(b) What will happen when:
(i) a burning splint of wood is introduced into a gas jar containing oxygen gas
(ii) oxygen gas reacts with metals .
(iii) hydrogen gas reacts with oxygen gas .........
(c) List four uses of hydrogen in our daily life.
(i) Isotopes are atoms of the same element that have different:
(ii) When substance A and substance B react to produce a new substance C, the reactants A and B are said to:
(iii) In the formula of the compound F2K3 the valences of F and K are respectively:
(iv) The process by which water is converted into water vapour or steam is called:
(v) In the Bunsen burner a sooty flame is most likely to be formed when the:
(vi) The best way to separate a mixture of iodine and iron fillings is by:
(vii) The choice of the source of heat depends on the:
(viii) When oxygen combines with metals they:
(ix) The pair elements which is most likely to form a covalent bond when they react together is:
(x) A calcium ion (Ca2+) differs from calcium atom (Ca) because a calcium ion has:
2. Match each item in List A with a response in List B by writing its letter against the corresponding item.
LIST A | LIST B |
(i) Burning gases that give out heat and light (ii) Coating iron objects using zinc metal (iii) Domestic water treatment and purification (iv) Heterogeneous mixture (v) Holds maximum of 8 electrons Intelligent guess on the cause of the problem (vii) Liquid metal (viii)Relights a glowing splint (ix) The burning material is a liquefied gas (x) Turns white anhydrous copper (Il) sulphate blue | A. Boiling and filtration B. Class C fire C. Distillation D. Energy shell 1 E. Energy shell 2 F. Experimentation G. Flame H. Galvanization I. Hydrogen J. Hypothesis K. Mercury L. Oxygen M. Solution N. Suspension O. Water |
SECTION B
3. (a) Why do atoms combine?
(b) A metal Z atomic number 12 combines with chlorine to produce a metal chloride. By means of diagrams illustrate the arrangement of electrons in Z before and after the reaction.
(c) An atom X of atomic number 14 combines with chlorine to form a chloride. What type of bond will be formed between the atoms?
4 What do you understand by the term "valency"?
(b) Calculate the oxidation number of the underlined elements: (i) NaOH
(ii) CO32-
(iii) Na3P04
(v) S02
(c) Explain three points on the importance of changing one state of matter to another.
5. Give two reasons why water is a compound.
(b) Write IUPAC names for each of the following compounds: (i) CaC03
(iii) NaHC03
(iv) )2
(v) KCl
(c) Describe a chemical test for water.
6. State the law of conservation of energy.
(b) Give two ways in which energy can be transformed from one form to another.
(c) List down two sources of heat in the laboratory.
7. (a) Define the term "empirical formula".
(b) An organic compound contains 26.7% carbon, 2.2% hydrogen and 71.1% oxygen. If its relative molecular mass is 90, determine its:
(i) Empirical formula
(ii) Molecular formula
(c) State three points of modern atomic theory that amend Daltons ideas.
8. (a) Differentiate between:
(i) an atom and an element
(ii) Combustion and rusting
(iii) a solute and a solvent
(iv) a compound and a mixture
(b) Give two applications of chemistry in everyday life
(c) Why most laboratory apparati are made of glass?
9. Below is part of the periodic table and the numbers represent atomic numbers. Study the table carefully then answer the questions that follow:
Write T in the space where a noble gas in period 3 would occupy. Write U in the space where the most active metal would occupy.
(iii) Write W in the space where the most active non-metal would occupy.
Write X in the space which would be occupied by an element in period 3 capable of forming a compound XW
(v) Write Y in group Il period 4 element.
Write Z in group VI period 3 element.
(b) Write the chemical symbols of the following elements:
(i) Argon
(ii) Sulphur
(iii) Boron
(iv) Silicon
(v) Phosphorus
(c) Write the formula of each compound formed between:
(i) Aluminium and chlorine
(ii) Potassium and oxygen
10. (a) (i) Name two reagents normally used for preparation of hydrogen in the laboratory.
(ii) Write a word equation for the reaction in (i) above.
(b) (i) Why is hydrogen gas used for filling balloons? (ii) Describe chemical test for hydrogen gas.
(c) Explain safety measures that should be taken when handling chemicals with the following warnings:
(i) Flammable
(ii) Corrosive
(iii) Irritant or Harmful
(iv) Toxic
(i) In scientific study, the tentative explanation for the observed chemical phenomenon can be proved by:
(ii) A certain liquid dissolves copper (Il) sulphate to form a blue solution. This liquid is likely to be:
(iii) When a chemist studies a substance he/she is interested in its:
(iv) The boiling point of pure water at sea level is 1000C and that of ethanol is 780C. The mixture of ethanol and water can be separated by:
(iv) The boiling point of pure water at sea level is 1000C and that of ethanol is 780C. The mixture of ethanol and water can be separated by:
(vi) Which group among the following elements are metals?
(vii) An electrovalent bond is formed by:
(viii) Petrol is an example of:
(ix) The electronic configuration of silicon is:
(x) The most abundant element on the earth is:
(viii) Petrol is an example of:
(ix) The electronic configuration of silicon is:
(x) The most abundant element on the earth is:
2. You are provided with two lists, A and B. Choose a word(s) from list B which matches the statement or phrase in list A and write down its letter.
LIST A | LIST B |
(i) Addition of hydrogen to a substance or removal of oxygen from a substance (ii) A way by which atoms become stable (iii) Coating • iron objects using zinc metal (iv) Modern scientific procedure (v) Environmental friendly fuel (vi) Method used to extract oil from nuts (vii) Speeds up the rate of chemical reaction (viii)Used for grinding solid chemicals (ix) Used in making electric bulb signs (x) Substance which can burn your skin | A. Biogas B. Bonding C. Catalyst D. Corrosive E. Data analysis F. Desiccator G. Galvanization H. Irritating I. Noble gases J. Mortar and pestle K. Painting L. Reduction M. Solution extraction N. Solvent extraction |
3. (a) (i) Explain what you understand by the word fuel.
(ii) Name the state of matter under which the following fuels belong:
Kerosene
Charcoal
Biogas
(b) Give two reasons to explain why non-luminous flame is normally used as a source of heat in the laboratory.
(c) (i) Define the term rust.
(ii) Mention conditions necessary for iron rusting.
4. (a) What do you understand by the following terms?
(i) First Aid
(ii) First Aid kit
(b) Name four components which can be found in a First Aid kit.
(c) Why is it important to provided First Aid to an injured person? (Give four reasons)
5. (a) A sample of chlorine gas contains 75% of 17Cl35 isotope and 25% of isotope 17 Cl37. What is the relative mass of chlorine atom?
(b) For each of the following indicate whether the process is a chemical or physical change:
(i) Burning of a candle ............
(ii) Decaying of meat
(iii) Souring of milk ............
(iv) Dissolution of common salt in water ............
(v) Sublimation of iodine from the mixture of iodine and sand ............
6. (a) What do you understand by the term element?
(b) Write a chemical symbol for each of the following elements: (i)Iron ......... (ii) Silver .........
(iii) Gold .
(iv) Sodium ......... (v) Helium .........
(c) Write down four substances which produce energy when burnt.
7. (a) If a mixture of manganese (IV) oxide, Mn02 with potassium chlorate. KCl03 is heated, which of the two compounds will produce oxygen?
(ii) Why? .
(b) Calculate the oxidation number of the underlined elements.
(ii) KC103
(iii) NH4+
8. (a) List down four assumptions of the Daltons Atomic Theory
(b) Write a chemical formula for each of the following compounds:
(i) Water
(ii) Potassium chloride
(iii)Magnesium oxide
(iv)Calcium hydroxide
(c) (i) What do you understand by the term "chemical warning signs"?
(ii) Draw the chemical warning sign that represents:
9. (a) Write down the method which can be used to separate the following mixtures:
(i) Sand and rice
(ii) Crude oil
(iii) Iron filings and table salt
(iv) Muddy water
(v) Chlorophyll from green leaves
(b) List down two uses of hydrogen gas in our daily life:
(c) Give three places or areas where the knowledge of Chemistry can be applied:
10. (a) List down three sources of natural water.
(b) Explain why water is not used to extinguish class E fires.
(c) Give a reason to support the following facts:
(i)Oxygen gas is collected over water.
(ii) Water is a universal solvent.
(iii)Group (VIII) elements cannot form compounds.