WASSCE CHEMISTRY MAY/JUNE 2019 (SSCE WAEC MAY/JUNE 2019 CHEMISTRY)

WASSCE CHEMISTRY MAY/JUNE  2019 (SSCE WAEC MAY/JUNE 2019 CHEMISTRY)

1. The periodic table is na arrangement of element according to their

A. oxidation number

B. atomic number

C. Mass number

D. Number of neutrons

 

2. A solid substance with high melting and boiling points is likely to be

A. covalent compound

B. a dative covalent compound

C. an electrovalent compound

D. a non metal

 

3.Which of the following metal reacts slowly with cold water

A. Iron

B. Silver

C. Calcium

D. Potassium

 

4. Which of the following elements has its highest ionization energy

A. Calcium

B. Chlorine

C. Fluorine

D. Magnesium

 

5. The bleaching action of chlorine is through the process of

A. hydration

B. hydrolysis

C. reduction

D. oxidation

 

6.  If 6.5 g of magnesium ribbon reacts completely with hydrochloric acid, how many grams of hydrogen gas would be librated?

$M{{g}_{(s)}}+2HCl(aq)\to MgC{{l}_{2(aq)}}+{{H}_{2(g)}}$

[H =1.0, Mg =24.0]

 

7. Calcium and magnesium belong to the same group of the periodic table because both

A. Are metals

B. form cations

C. form colourless salts

D. have same number of valence electrons

 

8. Which of the following substance is non polar

A. Br2

B. NH3

C. H2O

D. HBr

 

9. Which of the following pairs of component have the same molecular mass?

[H = 1.0, C =12.0, O =16.0]

A. Ethene and ethyne

B. Ethane and ethene

C. Carbon (II) oxide and ethene

D. Carbon (IV) and ethyne

 

10. When and equilibrium is established between dissolved and undissolved solutes, the solution is said to be

A. saturated

B. unsaturated

C. concentrated

D. diluted

 

11. How many moles of carbon (IV)oxide contain 16.0 g of oxygen

[C = 12.0, O =16.0]

A. 0.20 mol

B. 0.25 mol

C. 0.40 mol

D. 0.50 mol

 

12. Stoichiometry is based on the law

A. multiple proportion

B. constant composition

C. conservation of energy

D. conservation of mass

 

13. What is the percentage of mass of hydrogen CH3COOH?

(CH3COOH = 60]

A. 1.7%

B. 5.0%

C. 6.7%

D. 7.1%

 

14.Which of the following compounds has coordinate bond in its structure

A. Al2Cl6

B. MgCl2

C.AgCl

D.NaCl

 

15. The nature of the compound $C{{H}_{3}}C(C{{H}_{3}})C{{H}_{2}}C{{H}_{2}}C{{H}_{3}}$ is

A.  2 - methyl butane

B. 2, 2 . dimethyl butane

C. 2 - methyl pentane

D. 2, 2 - dimethyl pentane

 

16.The properties of good primary standard include the following except

A. high molecular mass

B. low molecular mass

C.  high degree purity

D. readily available

 

17. What is the solubility of a salt X at 25o C if the saturated solution of the salt contains 0.28 g in 100 cm3 of solution

[X = 56.0 g]

A. 0.05 mol dm-3

B.  0.10 mol dm-3

C. 2.60 mol dm-3

D. 2.80 mol dm-3

 

18.Vinegar is an aqueous solution of

A. hydrochloric acid

B. ethanedioic acid

C. ethanoic acid

D. hydrofluoric acid

 

19. Which of the following solutions containing one mole per dm3 of the compound would have the lowest pH

A. Ethanoic acid

B.  Hydrochloric acid

C. Sodium chloride

D. Sodium hydrotrioxocarbonate (IV)

 

20. A sample of air was bubbled into water. The pH of the water slowly changed from 7 to 6. Which of the following gases in the sample caused the change?

A. Carbon (IV) oxide

B. Carbon (II) oxide

C. Nitrogen

D. Oxygen

 

21. The most suitable indicator for the reaction between NaOH(aq) and HCOOH(aq) is

A. bromocresol

B.methyl orange

C. methyl red

D. phenolphthalein

 

22.  Consider the following reaction equation

            \[2Al{{(OH)}_{3}}+3{{H}_{2}}S{{O}_{4}}\to A{{l}_{2}}{{(S{{O}_{4}})}_{3}}+6{{H}_{2}}O\]

How many moles of tetraoxosulphate (VI) acid is needed to produce 0.5 mol of aluminum tetraoxosulphate(VI)

A. 0.5

B. 1.0

C. 1.5

D. 3.0

 

23. Which of the following pairs of substances has the highest heat of neutralization?

A. Strong acid and strong base

B. Weak acid and weak base

C. Strong acid and weak base

D.  Weak acid and strong base

 

24. When quicklime is dissolved in water

A. heat is absorbed

B. heat is evolved

C. oxygen is liberated

D. hydrogen is given off

 

25. If the value of ΔH is positive for a reaction, it means that the reaction is

A. exothermic

B. endothermic

C. Spontaneous

D. Slow

 

26. Which of the following compounds is formed by the oxidation of ethanol?

A. ${{C}_{2}}{{H}_{4}}C{{O}_{2}}H$

B.${{C}_{2}}{{H}_{5}}C{{O}_{2}}H$

C.$C{{H}_{3}}OH$

D. $C{{H}_{3}}C{{O}_{2}}H$

 

27. What is the characteristics of the gas liberated when dilute hydrochloric acid is added to iron(II) sulphide?

A. Turn lime water milky

B. Decolorizes bromine water

C. Gives a pop sound

D. Turn lead(II) ethanoate paper black

 

28. An organic compound contains 72% carbon 12% hydrogen and 16% oxygen by mass. What is the empirical formula of the compound? [H =1.0, C = 12.0, O = 16.0]

A.${{C}_{3}}{{H}_{8}}O$

B. ${{C}_{6}}{{H}_{12}}O$

C.${{C}_{6}}{{H}_{12}}{{O}_{2}}$

D.${{C}_{12}}{{H}_{12}}{{O}_{11}}$

 

29. When excess chlorine is mixed with ethane at room temperature, the product formed is

A. 1, 2 - dichlorothane

B. 1, 2 - dichlorothene

C. 1, 1 - dichlorothene

D. 1, 1 - dichloroethene

 

30. Which of the following reagent could be used to distinguish between propan-1-ol and propan-2-ol?

A. H+/K2Cr2O7

B. I2/OH-

C. CH3COOH

D. NaCl

 

31. If a catalyst is added to a system at equilibrium and the temperature and pressure remains constant, there would be no effect on the

A. activation energy of the reaction

B. rate of the forward reaction

C. rate of reverse reaction

D. heat of reaction

 

32. Consider the following reaction equation

$3C{{l}_{2}}+2N{{H}_{3}}\to {{N}_{2}}+6HCl$

NH3 is acting as

A. a reducing agent

B. a dehydrating agent

C. a drying agent

D. an oxidizing agent

 

33. The oxidation number of chromium in

A. +4

B. +5

C. +6

D  +7

 

34. The process by which alkanoic acid reacts reversibly with alkanols is known as

A. saponification

B. etherification

C. carboxylation

D. halogenation

 

35. If the oxidation potential Mg and Al are +2.37 and +1.66 volts respectively, then Mg would

A. not replace Al

B. be replaced by Al

C. remain in the solution

D. replace Al

 

36.Consider the reaction represented by the following equation

                        $2S{{O}_{2(g)}}+{{O}_{2(g)}}\rightleftharpoons 2S{{O}_{3}}(g)$

A decrease in pressure of the reaction would

A. decrease the concentration of SO2

B. has no effect on the reaction

C. Shift the equilibrium position to the left

D. shift the equilibrium position to the right

 

37. In a mixture of gases which do not react chemically together, the pressure of the individual gas is

A. atmospheric pressure

B. vapour pressure

C. total pressure

D. partial pressure

 

38. Biotechnology is applied in

A. treatment of sewage

B. treatment of water

C. purification of chemicals

D. purification of metals

 

39. Which of the following organic  compounds has the lowest boiling points

A. C6H14

B. C5H12

C. C4H10

D. (CH3)3CH

 

40. Consider the reaction represented by the following equation:

\[{{C}_{2}}{{H}_{2}}\xrightarrow{{{H}_{2}}}X\xrightarrow{{{H}_{2}}}Y\]

X and Y respectively are

A. ethane and ethene

B. ethene and ethane

C. ethyne and ethene

D. ethane and ethyne

 

41. Which of the following substance can be classified as heavy chemical

A. CaoCl­2

B. H2SO4

C. AgNO3

D. CaO

 

42. In Boyle's law,

A. T is constant, while P varies  directly with V

B. P is constant, while V varies inversely with T

C. V is constant, while P varies directly with T

D. T is constant, while V varies inversely with P

 

43. Which of the following apparatus is not used in volumetric analysis

A. pipette

B. Burette

C. Desiccator

D. Conical flask

 

44. One of the deduction from Rutherford's alpha particle scattering experiment is that

A. electrons are negatively charged

B. electrons have negligible mass

C. nuclei of atoms are positively charged

D. protons are positively charged

 

45. The atoms $_{29}^{64}Cu$ and $_{30}^{65}Cu$have the same number of

A. nuecleons

B. electrons

C. neutrons

D. protons

 

46. The number of electrons in the 3d orbitals of 24Cr is

A. 2

B. 3

C. 4

D. 5

 

47. The method used to collect a gas in the laboratory depends on its

I. boiling point

II. density

III. smell

IV solubility in water

 

A. I and II obnly

B. II and IV

C. III and IV

D. I, II, III and IV

 

48.Which of the following method is not used for the separation of mixtures

A. Chromatography

B.. Crystallization

C. Distillation

D. Electrolysis

 

49. The group to which elements belong in the periodic table is determined by the number of

A. electrons

B. core electrons

C. valence shells

D. valence electrons

 

50. Kipps apparatus can used to prepare

A. H2

B. NH3

C. O2

D. H2S

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