WASSCE chemistry mock questions

WASSCE chemistry mock questions

This is a WASSCE chemistry mock questions for Senior High Schools in the country. Candidates must practice the questions in order to prepare adequately for the examination.

 

See also: WASSCE core maths mock questions

OBJECTIVES TEST

1. The mass spectrometer can be used to measure the
a. Mass of an electron
b. Relative atomic mass of an atom
c. Mass of a proton in an atom
d. Mass of a neutron in an atom

 

2. How many electrons does 3- contain?
a. 12
b. 15
c. 18
d. 16

 

3. The element and are in the same group of the periodic table because they both have
a. The same number of shells
b. The same number of valence electron
c. The same size
d. The same degree of hardness

 

4. The periodic table is an arrangement of electrons according to their
a. Oxidation number
b. Number of neutrons
c. Mass number
d. Atomic number

 

5. Covalent compounds generally have relatively low melting points because they
a. Are organic compounds
b. Possess weak intermolecular forces
c. Are non-polar compounds
d. Are volatile liquids

 

WASSCE chemistry mock questions

6. The metallic bond in Magnesium is stronger than that in calcium because Magnesium has a
a. Larger atomic size
b. Greater number of valence electrons
c. Lower melting point
d. Smaller atomic size

 

7. The geometrical shape for the four hybridized orbital is
a. Linear
b. Tetrahedral
c. Trigonal planar
d. Trigonal pyramidal

 

8. A solution is prepared by dissolving 2.1g of NaOH in 250 of solution. What is the concentration of the
solution in mol/dm 3 ? [Na=23, O=16, H=1]
a. 0.013mol/dm 3
b. 0.21mol/dm 3
c. 0.53mol/dm 3
d. 8.40mol/dm 3

 

9. Which of the following statements about a molar solution is correct? It
a. Contains one mole of the solute in 1dm 3 of solution
b. Contains any amount of solute in a given volume of solution
c. Cannot dissolve more of the solute at that temperature
d. Is a supersaturated solution

 

10. Ethyne is used in
a. Making shoe polish
b. Hunter’s lamp
c. The extraction of iron
d. The generation of electricity

 

WASSCE chemistry mock questions

11. Which of the following processes occurs when palm wine is fermented?
a. Ethylethanoate is hydrolysed
b. Glucose is converted to ethanol
c. methanol is converted to ethanoate
d. ethanol is converted to ethanoic acid

 

12. The predominant intermolecular
force in alkanoic acid is
a. Electrostatic attraction
b. Van der Waal’s forces
c. Hydrogen bonding
d. Dipole-dipole interaction

 

13. Which of the following is the balanced equation for the reaction, which takes place when chlorine gas
is passed through an aqueous solution of sodium bromide?
a. + +           →

b. + +         →

c. +
d. +              →

 

14. The law of definite proportion states that
a. Matter can neither be created nor destroyed
b. Pure samples of substances are in the same proportion by mass
c. Chemical compounds are pure because they contain the same elements
d. Pure samples of the same compound contains the same elements combined in the same proportion by mass

 

15. One property of an Egyptian mummy, which can be estimated using the carbon dating technique is
a. Age
b. Original size
c. Original weight
d. Original height

 

WASSCE chemistry mock questions
16. Half-life of an element is the measure of the
a. Mass of its atom
b. Number of protons in its atoms
c. Number of isotopes of the element
d. Stability of the nucleus of its atoms

 

17. The burning of hydrogen in oxygen is given as +. At a temperature of 120 o C and 1atm pressure, 30cm³ of hydrogen was burnt in excess oxygen gas. If the final volume of the gases in the reaction was 100cm 3 , what was the initial volume of the oxygen?
a. 70cm³
b. 75cm³
c. 85cm³

d. 130cm³

18. Equal volumes of all gases under the same conditions of temperature and pressure contain the same number of molecules. This is an expression of
a. Boyle’s law
b. Dalton’s atomic theory
c. Avogadro’s hypothesis
d. Graham’s law of diffusion

 

19. Why are H₂SO₄ and CaCl 2 not suitable for drying ammonia gas?
a. They are corrosive
b. They are poisonous
c. They react with the gas
d. They pollute the gas

20. Which of the following pairs of gases produces dense white fumes when mixed
a. H₂S and HCl
b. H₂S and CO₂

c. NH₃ and CO₂

d. NH₃ and HCl

 

WASSCE chemistry mock questions

21. When an endothermic reaction occurs, the heat content of the product is
a. Less than that of the reactants
b. Greater than that of the reactant
c. The same as that of the reactant
d. Greater than that of the activated complex

 

22. Which of the following reactions are always exothermic
I. Neutralization
II. Decomposition
III. Combustion
a. I, II and III
b. II and III only
c. I and II only
d. I and III only

 

23. Which of the following metals exhibits variable oxidation state in its compound?
a. Aluminium
b. Chromium
c. Potassium
d. Scandium

 

24. Which of the following pairs of elements are transition metals?
a. Fe and Cu
b. Cu and Pb
c. Pb and Mn
d. Al and Cu

25. Chemical reactions tend to occur at a higher rate at a higher temperature because
a. Masses of the reacting particles become lower at a higher temperature
b. The activation energy of the reaction becomes lower at higher temperatures
c. The number of effective collisions is higher at higher temperature
d. The mechanism of the reaction at a higher temperature is different from that at a lower temperature

 

WASSCE chemistry mock questions

26. The minimum amount of energy required by colliding particles to form products is
a. Potential energy
b. Kinetic energy
c. Ionization energy
d. Activation energy

 

27. What conditions are required for the maximum yield of ammonia in the following reaction N₂(g) + 3H₂(g) in equilibrium 2NH₃(g) ∆H= -ve

a. High temperature and high pressure
b. Low temperature and high pressure
c. Low temperature and low pressure

d. High temperature and low pressure

28. A change in temperature of a saturated solution disturbs the equilibrium between the
a. Dissolved solute and the solvent
b. Dissolved solute and the undissolved solute
c. Dissolved solute and the solution
d. Undissolved solute and the solvent

 

29. What volume of 0.1mol/dm³ HCl is needed to neutralize 20.0cm³ of 0.1mol/dm³ Na₂CO₃ in the reaction Na₂CO₃ + 2HCl →  2NaCl + CO₂ + H₂O?
a. 40.0cm³
b. 25.0cm³
c. 20.0cm³
d. 10.0cm³

30. When exposed to air, concentrated hydrochloric acid would
a. Vaporize into hydrogen and chlorine gas
b. Become less concentrated
c. Become more concentrated
d. Absorb CO₂ from air

 

WASSCE chemistry mock questions

31. Which of the following substances will give white precipitate with tetraoxosulphate(VI) acid?
I. CaCl₂solution
II. CuSO₄ solution
III. AlCl₃ solution
IV. BaCl₂ solution
a. IV only
b. I and II only
c. III and IV only
d. I and IV only

 

32. Which of the following hydroxides is not readily soluble in water?
a. KOH
b. NaOH
c. Ca(OH)₂
d. NH₄OH

 

33. Which of the following reagents is used as a reducing agent?
a. F₂
b. H₂S
c. K₂Cr₂O₇

d. KMnO₄

 

35. If the oxidation potentials of Mg and Al are +2.37 and +1.66 volts respectively, then Mg would
a. Replace Al
b. Remain in the solution
c. Be replaced by Al
d. Not replace Al

 

WASSCE chemistry mock questions

35. What is the essential difference between a dry cell and a car battery
a. The dry cell consist of only one cell whilst the car battery consist of six cells
b. The dry cell is a secondary cell whilst the car battery is a primary cell
c. The reaction in the car battery is reversible whilst that of the dry cell is not.
d. The dry cell is a lead accumulator whilst the car battery is not

 

36. The function of the salt bridge in an electrochemical cell is to maintain
a. The concentration of the electrolyte
b. Equilibrium system
c. Electrical neutrality
d. High cell voltage

 

37. Which of the metals listed below is best purified by electrolytical means?
a. Aluminum
b. Copper
c. Gold
d. Iron

 

38. How long will it take to produce 7.8g of Al metal by the reduction of Al³⁺ ions in an electrolytic cell with a current of 2.0A? [1F= 96500C; Al=27]
a. 4.3 hours

b. 6.9 hours
c. 11.6 hours
d. 13.0 hours

39. In the extraction of Aluminium, the impurities in the bauxite are removed by
a. Burning the bauxite in the blast furnace
b. Electrolyzing molten bauxite
c. Mixing the bauxite with concentrated sodium hydroxide
d. Reacting the impurities with calcium oxide

 

40. Common salt (NaCl) is used for preserving food. Which of the following properties could be used to determine the purity before use?
a. Solubility in water
b. Crystallization nature
c. Relative density
d. Melting point

 

WASSCE chemistry mock questions

41. Which of the following substances is obtained through biotechnology?
a. Bauxite
b. Beer
c. Gold
d. Soap

42. An example of a biodegradable pollutant is
a. Hydrogen sulphide
b. Carbon (II) oxide
c. Plastic
d. Sewage

 

43. Which of the following mixtures can be separated by fractional distillation?
I. Crude oil
II. Ethanol in water
III. Green pigment in a leaf
a. I only
b. I and II only
c. I and III only
d. I, II and III

 

44. The most suitable process of obtaining water from an aqueous solution of sugar is
a. Crystallization
b. Filtration
c. Decantation
d. Distillation

45. Which of the following methods is not used for the separation of mixtures?
a. Chromatography
b. Crystallization
c. Distillation
d. Electrolysis

 

WASSCE chemistry mock questions
46. Cracking of petroleum is an important chemical process because it
a. Increases the boiling point of petrol
b. Increases the quantity of petrol
c. Reduces knocking
d. Increases the length of carbon chain of hydrocarbons

 

47. When concentrated tetraoxosulphate(VI) acid is added to an alkanol, the product formed is an
a. Alkene
b. Alkyne
c. Alkanoic acid

d. Alkanol