THE PRESIDENT’S OFFICE

REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

MADABA DISTRICT COUNCIL

DISTRICT MOCK EXAMINATION

032/1 CHEMISTRY 1 FORM FOUR

TIME 03:00 HOURS 22 JUNE 2021

 

 

INSTRUCTONS

  1. This paper consists of section A, B and C.
  2. Answer all questions in all sections.
  3. Calculators and cellular phones are not allowed in the examination room.
  4. Write your examination number on every page of your answer booklets/sheets.
  5. The following constants may be used,
  • LA = 6.-2 X 1023
  • GMV = 22.4dm3 at S.T.P
  • 1Llitre = 1dm3 = 1000cm3
  • IF = 96500 coulombs

    Atomic masses

    Na = 23. H =1, C = 12, O = 16, S = 32

     

    SECTION A (15 marks)

  1. For each of the item (i) – (x) choose the correct answer from the given alternatives and write its letter beside the item number in the answer book provided
    1. Which one of the following sects of laboratory apparatus are used for measuring volume?
      1. Crucible, U-tube and volumetric flask
      2. Test tubes, beakers, and glass jar
      3. Thistle funnel, separating funnel and beaker
      4. Burette, pipette and measuring cylinder
      5. Conical flask, test tube and measuring cylinder
    2. The empirical formula of certain compound is CH3. Its molar mass is 30g. What will be its molecular formula?
      1. CH4
      2. C2 H4
      3. C2 H6
      4. C2 H8
      5. C4 H12
    3. Fractional distillation process of a mixture of water and ethanol is possible because:
      1. Water and ethanol have the same boiling point
      2. Water has lower boiling point than ethanol
      3. Ethanol has lower boiling point than water
      4. Water and ethanol form partially immiscible liquid solution
      5. Water and ethanol are immiscible liquids
    4. Which of the following substances represent a group of acidic oxides?
      1. Carbon dioxide carbon monoxide, and Sulphur dioxide
      2. Sulphur trioxide, nitrogen dioxide and nitrogen monoxide
      3. Carbon dioxide, Sulphur dioxide and do nitrogen oxide
      4. Sulphur trioxide, carbon dioxide and nitrogen dioxide
      5. Carbon monoxide, nitrogen oxide and Sulphur dioxide
    5. What will be the molarity of a solution which contain 26.5g of anhydrous sodium carbonate in 2dm3 of solution
      1. 0.05M
      2. 0.25M
      3. 5.30M
      4. 0.025M
      5. 0.50M
    6. The Brownian movement is taken to be the evidence of the
      1. Theory of association of water molecules
      2. Theory of ionization of electrolytes
      3. Theory of colloidal suspensions
      4. Kinetic theory of behavior of substances
      5. Brownian theory
    7. One of the isotopes of an element X has an atomic number “Z” and a mass number A. What is the number of neutrons contained in the nucleus of the element X?
      1. Z
      2. A
      3. A + Z
      4. A – Z
      5. Z – A
    8. C3 H5Cl can be represented in different structures which are called
      1. Homologues series
      2. Isomers
      3. Structural formulae
      4. Identical structures
      5. Condensed structures
    9. …………………….is the general term used to explain a mixture of different metals
      1. Alloy
      2. Allotrope
      3. Amphoteric
      4. Amorphous
      5. Isotope
    10. A student whose hands are spilled out by acid in the laboratory should………………………. as first Aid
      1. Rinse the affected area by dilute acid
      2. Rinse the affected area by a piece of cloth or cotton wool
      3. Wash the affected area by strong base
      4. Wash the affected area by running water
      5. Wash the affected area by concentrated HCl

         

  2. Match the item in LIST “A” with the correct response in list “B”

LIST A

LIST B

  1. Lightest element
  2. An element of group (VII) of the periodic table
  3. Source of energy derived from animal wastes
  4. Form about 78% by volume of air
  5. The lightest noble gas
  1. Argon
  2. Helium
  3. Hydrogen
  4. Iodine
  5. Bio gas
  6. Biomass
  7. Nitrogen
  8. oxygen

 


SECTION B (70 marks)

  1. (a) Explain with the help of one chemical equation in each case, how
    1. temporary hardness of water is removed by boiling
    2. permanent hardness of water can be removed by using washing soda

    b) Outline three disadvantages of hard water

4. a) The atomic number of potassium is 19. Give three deductions which can be made

From this statement

b) The following element represent atoms of elements having their mass number and

atomic numbers Ar and K

  1. What is the electronic configuration of Argon atom?
  2. What is the electronic configuration of potassium ion (K+)
  3. How many neutrons are there in the nucleus of Argon atom
  4. Explain why argon atom has a lower atomic number but greater atomic mass compared to potassium?

5.a) Write a balanced chemical equation of

  1. Potassium hydroxide react with sulphuric acid
  2. Lead carbonate decomposed by heat

b) i) With chemical equation name the products formed when nitrates of potassium

and zinc decompose by heat

  1. Suggest why nitrates of zinc and potassium behave differently on heating
  1. a) Name the homologous series of organic compounds which are represented by the molecular formula
    1. CnH2n+2
    2. CnH2n
    3. CnH2n-2

    b) Write down all the possible isomers of the molecular formula C4 H9 Br

 

 

 

 

 

  1. a) One of the method used for the preparation of oxygen is by decomposition of

Hydrogen peroxide

 

MnO2

2H2 O2(aq) 2H20(i) + 02(g)

 

  1. what is the role of manganese (IV) oxide (Mn02 ) on the production of oxygen gas?
  2. what would happen if the reaction was made to proceed without manganese (IV) oxide?
  3. Calculate the volume of oxygen gas at S.T.P. which theoretically could be obtained from 50cm3 of a solution of hydrogen peroxide containing 68g/dm3
  4. Why oxygen gas is collected by upward delivery or downward displacement of water?
  1. a) 289500 coulombs were required to deposit one mole of a metallic element Q from its aqueous solution. Calculate the valence of Q

    b) The following experiment was used to electroplate a metallic neck chain. Study it and answer questions that follows: –

     


     

     

     

     

    1. Explain what happened to anode and cathode
    2. Write ionic equations for the reaction which occurred at the electrodes

 

  1. a) Calculate the oxidation number for the underline element
    1. Cr2 07
    2. K Cl 03
    3. Mn0

    b) An element A has atomic number 12 and an element B has atomic number 17

    1. Write the chemical formula when B combines with A
    2. What type of bond is formed?

c) Write down two characteristics of the type of bond involved in 8 b (ii) above

 

 

 

  1. a) Give two examples in each of the following (i) Solid fuel (ii) gaseous fuel

    b) The reaction which produce methanol from carbon Monoxide and hydrogen is represented by the equation

 

CO(g) + H2(g) CH30H(g)

  1. To get better yield of methanol what should be done on pressure
  2. The value of H is negative. What does this tell about the reaction?
  3. With reason state whether a high temperature or low temperature will give a better yield of methanol
  1. 0.48g of 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 (II) sulphate solution. Copper was filtered, washed with water dried at 1000C and the mass found to be 1.27g

    The balanced chemical equation of the reaction occurred was:

    M(s) + CuSO4(aq) MSO4(aq) + Cu(s)

Calculate

  1. The number of moles of copper that were formed and the number of moles of M that were used in the reaction
  2. The relative atomic mass of M and hence identify the element M
  1. Explain why?
    1. Chemistry laboratory should have fume chamber
    2. Sodium metal should be stored under paraffin oil
    3. Hydrochloric acid is an acid
    4. Concentrated H2SO4 is used in the preparation of chlorine gas
    5. Chlorine gas is diatomic
    6. Noble gases do not form compounds
    7. Group (I) elements are called ALIKAL METALS

     


SECTION (C) (15)

Answer only one question

  1. Describe the causes, two effects and measures to be undertaken in –order to prevent/reduce the amount of acid rain
  2. Using four examples, explain how the process of neutralization is important in day to day life.

 

 

 

 

 

 

 

 

 

 

 


 

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