FORM TWO CHEMISTRY ANNUAL EXAMS

THE PRESIDENT’S OFFICE MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCY BASED SECONDARY EXAMINATION SERIES

 

                                                            CHEMISTRY   FORM TWO

TIME: 2 HOURS                                                                                                      NOVEMBER 2022

INSTRUCTIONS

1. This paper Consist of sections A, B and C with total of 10 questions 

2. Answer all questions in both sections 

3. All writings should be in blue/black ink 

4. All diagrams should be drawn in pencil 

5. Write your assessment number at the top right corner 

 

SECTION A (15 Marks)

1. For each of the items (i)-(x), choose the correct answer from among the given alternative and write its letter in the box provide.

 (i)   At room temperature in which substances are particles furthest apart?

A.   Water

B.    Sodium chloride

C.    Magnesium

D.   Hydrogen

E.    Hydrochloric acid

(ii)In the molecules CH4, HCI, and H20 which atoms use all of their outer shell imageelectrons in bonding? 

A. C and C! 

B. C and H 

C. a and H

D. H and O 

E. C and O

(iii)  In the laboratory one spoon of sugar was mixed with 200cm3 of water in a beaker to form .mixture

A.   Suspension

B.    Homogeneous

C.    Emulsionimage

D.   Miscible

E.    Heterogeneous

(iv)   The part of the Bunsen burner which controls the amount of air to support burning of the gas is

A. Jet

B.  Air hole

C.  Chimney 

D. Collar

E. Gas inlet

(v)        A certain mixture contained 280cm3 of alcohol and 300cm3 of water in the round bottomed flask, a form I student separated this mixture by fractional distillation process. Why?

A.   The two components have approximately the same volume

B.    The volume of water is less than the volume of alcohol

C.    The two component differ in boiling point

D.   The two component differ in volume

E.    Both are liquids at room temperatureimage

(vi)     Which change of matter occurs when water is kept at (zero) OOC?

A.   Water and vapour

B.    Liquid to gas

C.    Liquid to solid

D.   Water to steam

E.    Water to ice

 (vii)   A non - luminous flame is suitable for heating because

A.   It is very noisy

B.    It is very hot

C.    It has no soot

D.   It is very large

E.    It produce light

(viii) Calcium ion and calcium atom both have the same

A.   Size

B.    Physical properties

C.    Number of protons

D.   Electronic configuration

E.    Charge

(ix)     Class B fire can be extinguished by using each of the following

A.   Oxygen and nitrogen

B.    Carbondioxide and sand

C.    Carbondioxide and water

D.   Sand and water

E.    Hydrogen and neon

(x)..........................has the highest percentage abundance in air

A.   Nitrogen

B.    Oxygen

C.    Noble gas

D.   Water vapour

E.    Carbondioxide

2. Choose a word(s) from LIST B which matches the statement in LIST A and write its letter in the table provided below.

LIST A

LIST B
  1. For measuring specific volume of liquids and transfer into another flask.
  2. For measuring volume of liquids or gases
  3. For estimating or measuring roughly volume of a solution.
  4. For measuring volume of a liquids and dispensing them.
  5. It is used to make up solution to a total volume during an experiment
  1. Beaker
  2. Burette
  3. Measuring cylinder
  4. Measuring flask
  5. Measuring syringe
  6. Pipette
  7. Volumetric flask

SECTION B: (70 MARKS)

Answer all questions in the space provided for each question

3. (a) There is a room at Mtakuja secondary school, having only the following features

  • Large windows
  •  One door open inwards
  • Slippery floor
  •  No water supply

Does the room qualify to be used as a chemistry laboratory? Give three reasons

(b) Calculate the molar mass of

(i) A1203

(ii) Ca(OH)2

(iii) C02

4.(a) 

 (b)Element T has 19 electrons and mass number of 39, what is the; (i) Atomic number of element T?

(ii)  Number of neutrons of element T?.

(iii) Number of protons of element T?

(iv)  Write the nuclide notation of element T.....

(v)   Give the name of element T....

(c) image204J 206K 207L and AM are isotopes of element Q whose abundances are 2%, 24%, 22% and 52% respectively. Calculate the mass number A of an isotope M, given that the relative atomic mass of element Q is 207

(d)A form Il student from Pwani secondary school conducted an experiment as follows:He boiled a hydrated copper (Il) sulphate blue solution in a crucible until all water evaporated. Explain the changes observed during experiment.

5.  (a) Mr Juma was passing through in the laboratory and found a beaker on top of a table. He picked up the beaker with his bare hand, accidentally the beaker cut his finger since it was broken. Suggest four possible items of the first aid and their function to help Mr Juma.

Items 

Function

 

 

 (b) Give any three reasons to support that sodium chloride is a compound but Air is a mixture of gases.

Sodium chloride as a compound

Air as a mixture of gases
  1. ....
  2. ....
  3. ...

 

6.  (a) Write the name of the following compounds

(i) (NH4)2C03

(ii) N204 

 (iii) FeC13

(b) Calculate the oxidation state of the underlined element in the given compound 

(i) KC103

(ii) PbO2

(c) Write the chemical formula for the following compound

(i)    Calcium nitrate

(ii)    Zinc hydroxide

 (iii)   Copper (I) oxide

7.  (a) The diagram below shows the position of some elements in the periodic table. Study it and answer the questions below Note: The letters given are not the actual symbols of elements

(i) Identify the most reactive non-metal......................................................................

(ii) Give the formula of only one stable ion with an electronic configuration of 2:8

(iii) Which letter represents an element with a positively charged ion............

(iv) Explain the trends of atomic radii from X to U...........................

 

(v)  Identify elements represented by letters; W, Z, X and Y

  1. W................................
  2. Z....................................
  3. X.....................................
  4. Y.......................................

(vi) State group and period of element X

Element 

Group 

Period.

 

 

 

 (vii)  Explain why element V is stored under paraffin or Kerosine?  

image(b) A large number of Tanzania society are using firewood and charcoal as a source of fuel for domestic uses because it is very cheap and readily available but it has a negative effect in the environment. Assess the effect of such fuel in the environment

(c) (i) Coal and Petroleum are said to be a natural source of fuel. Explain why they are termed as non -renewable source of energy?

 (ii) State the law of conservation of energy

 (iii)   Petrol acid kerosene are liquid fuel. When burn they release energy, identify what type of energy they produce? (Give any two points)

8.  (a) Organic compound M composed of 52.2% of carbon, 13% of hydrogen and the rest is oxygen. If the vapour density of compound M is 23 (i) Find the percentage of oxygen in a compound M

 

(ii)Calculate the empirical formula of compound M

 (iii)                      Calculate the molecular formula of compound M

 

9. (a) Draw a well labelled diagram of laboratory preparation of a colorless gas which support combustion at room temperature (without heating)

(b) State the property that support hydrogen gas to be used in

(i)  Production of margarine

 (ii) Making oxy — hydrogen flame.

(iii) Production of water gas

 (iv)  Filling of weather balloons......................

SECTION C: (15 MARKS)

10. (a) Four experiment were conducted using chemical A, B, C and D on different materials, the results were given as indicated below. You are required to write the correct terminology which suits each of the results given and draw the chemical warning signs which goes with it

(i)    When chemical A was poured on the wool it completely damage the surface of the wood

(ii)When chemical B was poured on the small fire, it found burst and turning a bigger fire

(iii) When chemical C was brought near the skin of some one, he started to imagecomplain that his skin was itching

(iv)  When chemical D was exposed on air sudden blust accompanied with light occurred.

Terminology

Terminology

Chemical warning sign
  1.         Chemical A is
  2.       Chemical B is
  3.    Chemical C is
  4.     Chemical D is

 

 

(b) List down any two importance of changing states of matter in our daily life

 

 

FORM TWO CHEMISTRY EXAM SERIES 126  

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FORM TWO CHEMISTRY EXAM SERIES 126  

THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCE BASED  SECONDARY EXAMINATION SERIES

ANNUAL  EXAMINATION

FORM TWO-2021

                                        CHEMISTRY

       032                                                

TIME: 2:30 HOURS                                                     November, 2021

image

Instructions

1.This paper consists of sections A and B with a total of ten (10) questions.

2.Answer all questions in the spaces provided.

3.All writings must be in blue or black ink except drawings which must be in pencil.

4.All communication devices and calculators are not allowed in the examination room.

5.Write Your Examination Number on the top right of every page.

6.The following atomic masses may be used.

H = 1, C = 12, O = 16, N = 14, S = 32, Zn = 65, Cl = 35.5, Na = 23.

FOR EXAMINER’S USE ONLY

QUESTION

NUMBER

SCORE

EXAMINER’S INITIALS

1

2

3

4

5

6

7

8

9

10

TOTAL

CHECKER’S INITIALS

SECTION A: (20 Marks)

1.Write down the letter corresponding to the most correct answer in the box provided for each item.

(i) How many protons, neutrons and electrons are there in an atom represented by image?

B.17                    18                    17

C.18                    17                    35 

D. 17                      35                 18.

(ii) Which of the following methods is used to separate salt from sea water?

A.Filtration

B.Decantation

C.Decantation

D.Fractional distillation.

(iii)Which of the following warning signs is likely to appear on a gallon containing methylated spirit in the laboratory?

A.Irritant

B.Flammable

C.Oxidant D. Explosion.

(v)Hydrogen peroxide image(iv) X + water. “X” represents _________

A.Oxygen

B.Hydrogen

C.Nitrogen 

D. Carbondioxide.

(vi)If a Bunsen burner produces much soot, which is the correct conclusion?

A.The air hole is closed

B.The burner gas jet is big

C.The air hole is fully opened

D.The gas supply is poor.

(vii)Which of the following is the list of group (II) element?

A.Sodium and magnesium

B.Calcium and carbon

C.Magnesium and calcium

D.Boron and Beryllium.

(viii)Element M of group I combines with element X of group VI, the formula of the compound formed when M combines with X is:

A.MX2

B.MX6

C.X2m

D.M2X.

(ix)The pair of elements which is most likely to form a covalent bond when reacted together is:

A.Carbon and chlorine

B.Aluminium and oxygen

C.Magnesium and oxygen

D.Sodium and chlorine.

(x)One of the following can distinguish hydrogen gas from other gases: A. It burns and supports combustion

B.It is colourless and ordourless C.It gives a smell of a rotten egg

D.It burns with pop sound.

(xi)The following sentences suggest that air is a mixture, except:

A.Its components can be separated physically

B.Its composition varies from one place to another

C.Its properties depends on individual gases

D.Its formation requires absorption or reabsorption of heat.

2.(a) Choose a word(s) from list B which matches the statement or phrases in list A and   write its letter in the space provided.

LIST A

LIST B

(i)Factors that can be manipulated to get desired results

(ii)A factor that is kept constant

(iii)Scientist’s best possible answer

(iv)Statement of how the results related to hypothesis

(v)First step in scientific method of studying a problem

A.Controlled variable

B.Hypothesis

C.Observation

D.Conclusion

E.Independent variable

F.Identification of a problem

G.Experimentation

H.Data analysis

Answer:

List A

(i)

(ii)

(iii)

(iv)

(v)

List B




2.   (b) Fill in the blanks below with the correct words.

(i)A candle flame is not good for glass ware because _____________________

(ii)A catalyst used for the production of oxygen gas from hydrogen peroxide is _______________________

(iii)A sudden unexpected occurrence that destroy properties and cause injury is called __________________________

(iv)It is used as fuel in rockets due to its lightness _________________________

(v)Blockage of the upper part of airway by food or other objects is called 

                            ________________________________

SECTION B: (80 Marks)

Answer all questions in this section

3. (a)  What is fuel?

___________________________________________________________________________

_____________________________________________________________________

          (b) (i)       State four types of fuels used by many Tanzanians:

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

                                                                                                        @ 1 mark = 04 marks

(ii) Why do you think many Tanzanians prefer to use the mentioned sources in 3b(i) above? Give two best reasons.

_______________________________________________________________

_______________________________________________________________

                                                                                                        @ 02 marks = 04 marks

4. You are provided with the following materials from chemistry laboratory:

Apparati: Thistle funnel, delivery tube, beehive self, trough, gas jar, flat bottomed flask with its coke. 

      Chemicals:Water, zinc granules, dilute hydrochloric acid.

(a)What chemical substance can be prepared using the materials mentioned above?

_____________________________________________________________________

(b)Draw the diagram showing how you could arrange the Apparati above in order to prepare a chemical substance you mentioned in 4(a) above. 05 marks

(c)How can the products mentioned in 4(a) above be collected?____________________________________________________________________

____________________________________________________________________

                                                                                                                  02 marks

    (d) Give at least three (3) uses of the product you mentioned in 4(a) above based on its             properties.

(i)______________________________________________________________

(ii)______________________________________________________________

(iii)______________________________________________________________

5. (a) What should you do immediately if:

(i)The piece of broken beaker cuts your finger

_______________________________________________________________

(ii)Chemicals splash on your face

_______________________________________________________________

(iii)Your shirt has caught fire

_______________________________________________________________

(iv)Your fellow student swallows unknown chemical substance thinking that it was water

_______________________________________________________________

                                                                                                @ 02 marks = 08 marks

    (b) Why do you think first aid is an important thing? Give two points:

(i)___________________________________________________________

(ii)___________________________________________________________

                                                                                                @ 01 mark = 02 marks

6.  (a)  (i)         A table salt is a common name for the compound with the formula NaCl. 

                          Write the systematic name for the table salt

_______________________________________________________________

_______________________________________________________________

                                                                                01 mark                                               

(ii) Briefly describe why molecular formula better preferred than empirical formula is_______________________________________________________________ _______________________________________________________________

_______________________________________________________________

                                                                                            02 marks

(b)   A compound consists of 27% sodium, 16.5% nitrogen and 56.5% oxygen by mass. If its molecular mass is 85g, find:

(i)Its empirical formula                                                  05 marks

(ii)Molecular formula                                                      02 marks

7.  (a)  Briefly explain the following terms: 

(i)Periodicity

_______________________________________________________________

_______________________________________________________________

(ii)Electronegativity

_______________________________________________________________

_______________________________________________________________

(iii)Ionization energy

_______________________________________________________________

_______________________________________________________________

(iv)Atomic radii/size.

_______________________________________________________________

_______________________________________________________________

                                                                                                        @ 01 mark = 04 marks

(b)  Why are certain elements in the period table referred to as metalloids? Give two examples of such elements:

Reason: ____________________________________________________________   

                                                                                                                02 marks

Example:

(i)_____________________________________________________________

(ii)_____________________________________________________________

                                                                                                  @ 00 ½ mark

(c)  Element X has atomic number of 19 and neutron number 20. Write down its:

 (i)        Electronic configuration

                               ______________________________________________________________

                                                                                                                01 mark

                (ii)       Mass number                                                              02 marks

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

8.(a)    (i)     Differentiate combustion from rusting.

     _______________________________________________________________

     _______________________________________________________________

 (ii)    Explain why cars and corrugated iron sheets in coastal areas like Dar es

Salaam, Tanga and Zanzibar get rust more quickly than in other cities of

    Tanzania like Mbeya, Mwanza and Arusha?                         02 marks

_______________________________________________________________

 _______________________________________________________________

(b)Explain how you can put off each of the following types of fire

(i)A fire started by petrol in a container                             02 marks

 _______________________________________________________________

  _______________________________________________________________

(ii)A fire started by a short circuit in an electric wire                     02 marks

 _______________________________________________________________

(iii)A fire caused by a burning magnesium metal                02 marks

 _______________________________________________________________

9.(a) With an example give the meaning of the following terms as applied in Chemistry:

(i)A radical                                                                            02 marks

_______________________________________________________________

_______________________________________________________________

(ii)Oxidation state                                                                     02 marks_______________________________________________________________ _______________________________________________________________

(b)Find the oxidation numbers of the following underlined elements:

(i)        Na        01mark                                                (ii)      HNO3     01mark

                (iii)      H2SO4       01mark                                         (iv)     SO32-          01mark

 (c)       Draw diagrams showing the electron transfer in the formation of MgCl2.

10.  (a)     Differentiate the following terms:

(i)An element and an atom

__________________________________________________________________

__________________________________________________________________

(ii)A compound and a mixture

__________________________________________________________________

__________________________________________________________________

(b)        Melting of ice and burning of papers are two processes that happen almost daily in our life.

(i)Identify the two actions as being physical or chemical change.

Ice melting __________________________________________________ 

Paper burning ________________________________________________

(ii)Mention two significant things that happen when the paper is burnt:

_______________________________________________________________ _______________________________________________________________

 (c)       What are the names of elements represented by the following symbols?

(i)K _________________________________________________________

(ii)S _________________________________________________________

(d)       Why some elements have their symbols written in one letter while others have   two letters? (e.g. N and Na) 


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