enwaecchemistry2016

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THEORY QUESTIONS

WAEC SYLLABUS

1. The following atom of carbon 12 6C, 136C and 146C can be described as.

A. Allotropes.

B. Isomers.

C. Isotopes.

D. Isotones

2. An Atom X consists of 6 protons and 7 neutrons. Which of the following representations of the atom is correct?

A. 136X

B. 137X

C. 136X

D.197X

3. How many electrons are present in 94Be2+?

A. 2.

B.4

C.5

D.6

4. When element 20Y combines with element 8Z.

A. A covalent compound, YZ is formed.

B. A covalent compound, ZY is formed.

C. An ionic compound. YZ is formed

D. An ionic compound, ZY is formed

5. The boiling point of HF. H2 AND NH3 increase in the order of

A. NH₃ < H₂O < HF.

B. H₂O < HF < NH₃

C. HF < NH₃ < H₂O

D. NH₃ < HF < H₂O

ANSWERS

6. Chemicals that are produce in small quantities and with very high degree of purity are.

A. Bulk chemical.

B. Fine chemicals.

C. Heavy chemicals.

D. Light chemicals

7. The mass of potassium hydroxide required to make 300.0cm^-3 of 0.4 moldm^-3 solution is [KOH=56.0]

A. 26.88g.

B. 13.44 g

C. 6.72 g

D. 3.36 g

8. Metals can be stretched into wires because they are.

A. Ductile

B. Good conductors.

C. lustrous.

D. Malleable

9. Aluminum is used in the manufacture of aircraft because it.

A. Is hard and brittle.

B. is light and resists corrosion.

C. has high density and conducts electricity.

D. Is malleable and double

10. An unsaturated solution differs from a saturated solution at a given temperature because it.

A. Cannot dissolve more solute

B. Can hold more solute than it can actually dissolve

C. Can still dissolve more solute at that given temperature

D. From crystal more easily on cooling

ANSWERS

11. Which of the following arrangement shows increasing order of reactivity of the halogens?

A. F₂ > C1₂ > Br₂ >1₂

B. 1₂ < Br₂ < C1₂ < F₂

C. F₂ < C1₂ < Br₂ >1₂

D. 1₂ > Br2 >C1₂ > F₂

12. The shape of the water molecule is.

A. Linear.

B. Pyramidal.

C. Tetrahedral.

D. V-shaped

13. Which of the following element will produce colored ion in aqueous solution?

A. Calcium.

B. Copper.

C. Magnesium.

D. Sodium

14. The minimum amount of energy required g0or effective collision between reacting particles is known as?

A. Activation Energy.

B. Bond Energy.

C. Kinetic Energy.

D. Potential Energy

15. The bond formed between H2O and H+ to form the Hydroxonium ion H2O+ is?

A. Dative

B. Covalent.

C. Electrovalent.

D. Ionic

ANSWERS

16. Elements X from the following oxides X2O, XO and XO2. This phenomenon illustrates the law of.

A. Conservation of mass.

B. Definite Proportion

C. Mass action

D. Multiple Proportion

17. How many moles of oxygen contain 1.204 x 10²⁴ molecules? [Avogadro’s constant (NA) = 6.02 x 10²³]

A. 1

B. 2

C.3

D.4

18. Which of the following statement about solids is correct?

A. Solids particles are less orderly than

B. Solids has lower densities than liquids

C. Solids particles have greater Kinetic energies than those of liquids

D. Solids particles cannot be easily compressed

19. Which of the apparatus can be used to measure a specific volume of a liquid accurately?

A. Beaker.

B. Conical Flask.

C. Measuring Cylinder.

D. Pipette

20. The general gas equation PV/T = k is a combination of.

A. Boyle’s and Charles’s laws

B. Boyle’s and Graham’s laws

C. Charles’s and Graham’s laws

D. Dalton’s and Graham’s laws

ANSWERS

21. The spreading the scent of a flower in a garden is an example of

A. Brownian motion.

B. Diffusion.

C. Osmosis.

D. Tynadal effect

22. Propane and carbon(IV)oxide diffuse at the same rate because [H = 1.00, C. = 12.0, O.=16.0]

A. They are both gas.

B. their molecule contains carbon.

C. they have the same relative molecular mass.

D. both is denser than air.

23. The energy which accompanies the addition of an electron to an isolated gaseous atom is.

A. Atomization.

B. Electro negativity.

C. Electron Affinity.

D. Ionization

24. An aqueous solution (NH₄)₂ SO₄ is.

A. Acidic.

B. Alkaline.

C. Amphoteric.

D. Neutral

25. When NH4CI(S) is dissolved in water, the container feels cold to touch. This implies.

A. The process is endothermic

B. The process is exothermic

C. NH4CI forms a saturated solution

D. NH4CI is highly soluble in water

ANSWERS

26. The PH of four solutions, M, N, Q and 2, 6, 8 and 11 respectively. Which of the following deductions about the solution is correct?

A. the PH of N is increased when the solution is diluted

B. the PH of Q is increased when the solution is evaporated

C. M is the most Alkaline solution

D. R is the most Acidic solution

27. Consider the following reaction equation H3O+ (aq) OH- (aq) → 2H2O(1), The reaction represents

A. Etherification.

B. Hydrolysis.

C. Neutralization.

D. Redox

28. The refreshing characteristic taste of fizzy drinks is due to the presence of

A. Carbon (IV) oxide.

B. Glucose.

C. Hydrogen.

D. sodium citrate

29. Chemical equilibrium is obtained when

A. All the reaction have been completely used up

B. The reaction goes to completion

C. The concentration of reaction and products remain constant

D. The concentration of reaction and products are equal

30. Which of the following factors will affect the rate of the reaction represented by the following equation? 2HCI_(aq)+ CaCO_3(s) → CaCI_2(aq) + H₂0_(I) + CO_2(g) I. Pressure II Concentration III Nature of Reactions IV. Temperature

A. I and II only

B. II, III and IV only

C. I, II and III only

D. I, II III and IV

ANSWERS

31. On evaporation to dryness, 350cm³ of saturated solution of salt Z gave 55,5g of salt. What is the solubility of the salt?

A. 1.57moldm^-3

B. 3.14 moldm^-3

C. 6.28 moldm^-3

D. 12.56 moldm^-3

32. Which of the following salt when dissolved in water will form a solution that will change blue litmus to red?

A. CH₃COONa

B. NH₄CI

C. NaCI

D. KCI

33. Which of the following bands are broken when ethanol is boiled? I Covalent bonds II Ionic bonds III Hydrogen bonds

A. I only

B. II only

C. III only

D. I, II and III

34. A compound with molecular formula CH₂O₂ is.

A. A carbohydrate

B. a carboxylic acid

C. an alkanol

D. an ester

35. The quality of electricity required to discharge 1 mole of univalent ion is

A. 9600C

B. 48250C

C. 96500C

D. 193000C

ANSWERS

36. Chlorine water is used as a bleaching agent because it is.

A. an acid solution.

B. an alkaline solution.

C. an oxidizing agent.

D. a reducing agent

37. Which of the following substance is a non-electrolyte.

A. H₂SO₄

B. CH₃COOH

C. C₆H₁₂O₆

D.NH₄CI

38. The oxidation number of sulphur is +4 in

A. Na₂S₂O₃

B. H₂SO₃

C. H₂SO₄

D. SO₃

39. Consider the following ionic equation Cr₂O7^2- + 14h+ + ne^- →2Cr³⁺ + 7H2o. The value of n ion the equation is

A. 7

B. 6

C. 3

D. 2

40. Consider the following half-cell reactions: AI(s) →AI³⁺ _(aq) + 3e^- Cu2+ _(aq) + 2e →Cu_(s)

A. AI_(s)+ Cu²⁺ (aq) → AI³⁺ _(aq) + Cu_(s)

B. 2AI_(s) + Cu²⁺ (aq) → 2AI³⁺ _(aq) + Cu_(s)

C. 2AI_(s) + 3Cu²⁺ (aq) → Cu_(s) + 2AI³⁺ _(aq)

D. 3AI_(s) + 2Cu⁺² _(aq)→ 2Cu_(s) + 3AI³⁺ _(aq)

ANSWERS

41. Amino acid are obtained from proteins by

A. Hydrolysis.

B. Oxidation.

C. Polymerization.

D. Reduction.

42. When a compound X is heated with concentrated tetraoxosulphate (IV) acid. It produces on alkenes’ X is an

A. Alkenes

B. Alkanol.

C. Alkanote

D. Alktne

43. Ripening of fruits is hastened by using

A. Ethanol

B. Ethane

C. Ethene

D. Ethyne

44. The compound that makes palm wine taste sour after exposure to the air for few days is.

A. Ethanol

B. Ethanoic acid

C. Methanol

D. Mechanic acid

45. Which of the following compounds is /are secondary alkanols. I. CH₃CH(CH₃)CH₃OH II. CH₃CH₂CH(OH) CH₃ III. CH₃C(OH)(C-I3)CH₃

A. I only.

B. ii only

C. I and III only.

D. ii and III only

ANSWERS

46. Consider the following reaction equation C₂H _4(g)+ 30_2(g) → 2CO_2(g) +2H₂O₍₁₎ The volume of oxygen at S.T.P that will be required to burn 14gofethene is. [C2H4 = 28: Molar volume of gas at s. t. p = 22.4dm³]

A. 67.2 dm³

B. 33.6 dm³

C. 11.2 dm³

D. 3.73 dm³

47. Which of the following sources of energy contributes to the Green- House effect?

A. Natural gas.

B. Nuclear.

C. Wind.

D. Solar

48. A consequence of global warming is?

A. Air pollution.

B. Flooding.