2016 WAEC (WASSCE) Chemistry Past Questions & Answers

Question 1

When a compound X is heated with concentrated tetraoxosulphate(VI)acid, it produces an alkene. X is an

Accepted Answer

B. Alkanol

Answer

A. Alkane

Answer

C. Alkanoate

Answer

D. Alkyne

Question 2

When NH4Cl(s) is dissolved in water, the container feels cold to touch. This implies

Accepted Answer

A. The process is endothermic

Answer

B. The process is exothermic

Answer

C. NH4Cl forms a saturated solution

Answer

D. NH4Cl is highly soluble in water

Question 3

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

Accepted Answer

D. Pipette

Answer

A. Beaker

Answer

B. Conical flask

Answer

C. Measuring cyclinder

Question 4

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

Accepted Answer

C. 96500C

Answer

A. 9600C

Answer

B. 48250C

Answer

D. 193000C

Question 5

An atom X consist of 6 protons, 6 electrons and 7 neutrons. Which of the following representations of the atom is correct?

Accepted Answer

A. 136X

Answer

B. 137X

Answer

C. 196X

Answer

D. 197X

Question 6

The pH of four solutions M,N,Q and R are 2,6,8 and 11 respectively. Which of the following deductions about the solutions is correct?

Accepted Answer

A. The pH of N is increased when the solution is diluted

Answer

B. The pH of Q is increased when the solution is evaporated

Answer

C. M is the most alkaline  solution

Answer

D. R is the most acidic solution

Question 7

Which of the following substances is a non-electrolyte?

Accepted Answer

C. C6H12O6

Answer

A. H2SO4

Answer

B. CH3COOH

Answer

D. NH4Cl

Question 8

The following atoms of carbon 126C, 136C and 146C can be described as?

Accepted Answer

C. Isotopes

Answer

A. Allotropes

Answer

B. Isomers

Answer

D. Isotones

Question 9

Which of the following elements would produce coloured ion in agueous solution?

Accepted Answer

B. Copper

Answer

A. Calcuim

Answer

C. Magnesuim

Answer

D. Sodium

Question 10

Which of the following sources of energy contributes to green-house effect?

Accepted Answer

A. Natural gas

Answer

B. Nuclear

Answer

C. Wind

Answer

D. Solar

Question 11

The alkanol obtained from the production of soap is

Accepted Answer

C. Trihydric Alkanol

Answer

A. Dihydric Alkanol

Answer

B. Tertiary Alkanol

Answer

D. Monohydric Alkanol

Question 12

The minimum amount of energy required for effective collisions between reacting particles is known as

Accepted Answer

A. Activation energy

Answer

B. Bond energy

Answer

C. Kinetic energy

Answer

D. Potential energy

Question 13

Consider the following half-cell reactions. Al(s) $	o$ Al3+(aq) + 3e- Cu2+(aq) + 2e- $	o$ Cu(s) The overall equation for the reaction is

Accepted Answer

C. 2Al(s) + 3Cu2+(aq) $	o$ 3Cu(s) +  2Al3+(aq)

Answer

A. Al(s) + Cu2+(aq) $	o$  Al3+(aq) + Cu(s)

Answer

B. 2Al(s) + Cu2+(aq) $	o$ 2Al(aq) + Cu(s)

Answer

D. 3Al(s) + 2Cu2+(aq) $	o$ Cu(s) + 3Al3+(aq)

Question 14

The shape of the water molecule is_______?

Accepted Answer

D. V-shaped

Answer

A. Linear

Answer

B. Pyramidal

Answer

C. Tetrahedral

Question 15

The general gas equation $\frac{PV}{T}$ = K is a combination of

Accepted Answer

A. Boyle's and Charles' laws

Answer

B. Boyle's and Graham's laws

Answer

C. Charles' and Graham's laws

Answer

D. Dalton's and Graham's laws

Question 16

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

Accepted Answer

C. Electron affinity

Answer

A. Atomization

Answer

B. Electronegativity

Answer

D. Ionization

Question 17

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

Accepted Answer

C. III only

Answer

A. I only

Answer

B. II only

Answer

D. I, II, III

Question 18

Which of the following factors will affect the rate of the reaction represented by the following equation? 2HCl(aq) + CaCO3(s) $\rightarrow$ CaCl2(aq) + H2O(1) + CO2(g) I. Pressure II.Concentration III. Nature of reactants IV. Temperature

Accepted Answer

B. II, III and IV only

Answer

A. I and II only

Answer

C. I, II and III only

Answer

D. I, II. III and IV

Question 19

Amino acids are obtained from proteins by

Accepted Answer

A. Hydrolysis

Answer

B. Oxidation

Answer

C. Polymerization

Answer

D. Reduction

Question 20

An aqueous solution of (NH4)2 SO4 is

Accepted Answer

A. Acidic

Answer

B. Alkaline

Answer

C. Amphoteric

Answer

D. Neutral

Question 21

Consider the following reaction equation H3O+(aq) + OH(aq) $\rightarrow$ 2H2O(1) The reaction represents

A.Esterification
B.Hydrolysis
C.Neutralization
D.Redox

Show answer

Answer: C. Neutralization

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Accepted Answer

B. 33.6dm3

Answer

A. 64.2dm3

Answer

C. 11.2dm3

Answer

D. 3.73dm3

Question 22

How many electrons are present in $^9_4Be^{2+}$?

Accepted Answer

A. 2

Answer

B. 4

Answer

C. 5

Answer

D. 6

Question 23

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

Accepted Answer

C. Can still dissolve more solute at given temperature

Answer

A. Cannot dissolve more solute

Answer

B. Can hold more solute than it can actually dissolve

Answer

D. Form crystal more easily on cooling

Question 24

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

Accepted Answer

C. They have the same relative molecular mass

Answer

A. They are both gases

Answer

B. Their molecules contain carbon

Answer

D. Both are denser than air

Question 25

Which of the following compounds is/are secondary alkanols? i) CH3CH(CH3)CH3OH ii) CH3CH2CH(OH)CH3 iii) CH3C(OH)(CH3)CH3

Accepted Answer

B. II only

Answer

A. I only

Answer

C. I and III only

Answer

D. II and III only

Question 26

Chemicals that are produced in small quantities and with very degree of purity are

Accepted Answer

B. Fine chemicals

Answer

A. Bulk chemicals

Answer

C. Heavy chemicals

Answer

D. Light chemicals

Question 27

The bond formed between H2O and H+ to form the hydroxonium H3O+ is

Accepted Answer

A. Dative

Answer

B. Covalent

Answer

C. Electrovalent

Answer

D. Ionic

Question 28

A compound with molecular formula CH2O2 is

Accepted Answer

B. A Carboxylic acid

Answer

A. A Carbohydrate

Answer

C. An alkanol

Answer

D. An ester

Question 29

An element X froms the following oxides X2O, XO and XO2. This phenomenon illustrates the law of________?

Accepted Answer

D. Multiple proportion

Answer

A. Conservation of mass

Answer

B. Definite proportion

Answer

C. Mass action

Question 30

Ripening of fruits is hastened by using

Accepted Answer

C. Ethene

Answer

A. Ethanol

Answer

B. Ethane

Answer

D. Ethyne

Question 31

The spreading of the scent of a flower in a garden is an example of_____?

Accepted Answer

B. Diffusion

Answer

A. Brownian motion

Answer

C. Osmosis

Answer

D. Tynadal effect

Question 32

The mass of potassium hydroxide required to make 300.ocm3 of 0.4 mol$dm^{-3}$ solution is {KOH = 56.0}

Accepted Answer

C. 6.72g

Answer

A. 26.88g

Answer

B. 13.44g

Answer

D. 3.36g

Question 33

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

Accepted Answer

B. NH4Cl

Answer

A. CH3COONa

Answer

C. NaCl

Answer

D. KCl

Question 34

Consider the following reaction equation H3O+(aq) + OH(aq) $\rightarrow$ 2H2O(1) The reaction represents

Accepted Answer

C. Neutralization

Answer

A. Esterification

Answer

B. Hydrolysis

Answer

D. Redox

Question 35

Which of the following arrangements shows increasing order of reactivity of the halogens?

Accepted Answer

B. I2 < Br2 < Cl2< F2

Answer

A. F2 > Cl2 > Br2 >I2

Answer

C. F2 < Cl2 < Br2< I2

Answer

D. I2 > Br2 > Cl2 > F2

Question 36

Chemical equilibrium is attained when

Accepted Answer

C. The concentration of reactants and products remain constant

Answer

A. All the reactants have been completely used up

Answer

B. The reaction goes to completion

Answer

D. The concentration of reactants and products are equal

Question 37

Chlorine water is used as a bleaching agent because it is

Accepted Answer

C. An oxidizing agent

Answer

A. An acidic solution

Answer

B. An alkaline solution

Answer

D. A reducing agent

Question 38

The refreshing characteristic taste of fizzy drinks is due ot the presence of

Accepted Answer

A. Carbon(IV)oxide

Answer

B. Glucose

Answer

C. Hydrogen

Answer

D. Sodium Citrate

Question 39

The boiling points of HF, H2O and NH3 increase in the order of

Accepted Answer

D. NH3 < HF < H2O

Answer

A. NH3

Answer

B. H2O < HF

Answer

C. HF < NH3 < H2O

Question 40

Which of the following metals is common to both brass and bronze?

Accepted Answer

B. Copper

Answer

A. Aluminium

Answer

C. Lead

Answer

D. Iron

Question 41

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

Accepted Answer

B. 2

Answer

A. 1

Answer

C. 3

Answer

D. 4

Question 42

When element $_{20}$Y combines with element $_8$Z, it forms

Accepted Answer

C. An ionic compound, YZ is formed

Answer

A. A covalent compound , YZ is formed

Answer

B. A covalent compound, ZY is formed

Answer

D. An ionic compound, ZY is formed

Question 43

Aluminium is used in the manufacture or aircraft because it

Accepted Answer

B. Is light and resists corrosion

Answer

A. Is hard and brittle

Answer

C. Has high density and conducts electricity

Answer

D. Is malleable and ductile

Question 44

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

Accepted Answer

B. Ethanoic acid

Answer

A. Ethanol

Answer

C. Methanol

Answer

D. Methanoic acid

Question 45

Consider the following ionic equation: Cr$_2$O$_7$$^{2-}$ + 14H$^+$ + ne-  → 2Cr$^{3+}$ + 7H$_2$O. The value of n in the equation is_______?

Accepted Answer

B. 6

Answer

A. 7

Answer

C. 3

Answer

D. 2

Question 46

The oxidation number of sulphur is +4 in

Accepted Answer

B. H2SO3

Answer

A. Na2S>2O3

Answer

C. H2SO4

Answer

D. SO3

Question 47

Metals can be stretched into wires because they are

Accepted Answer

A. Ductile

Answer

B. Good conductors

Answer

C. Lustrous

Answer

D. Malleable

Question 48

On evaporation to dryness, 350cm$^3$ of saturated solution of salt Z gave 55.5g of salt. What is the solubility of the salt? [Z = 101]

Accepted Answer

A. 1.57 mol$dm^{-3}$

Answer

B. 3.14 mol$dm^{-3}$

Answer

C. 6.28 mol$dm^{-3}$

Answer

D. 12.56 mol$dm^{-3}$

Question 49

A consequences of global warming is

Accepted Answer

B. Flooding

Answer

A. Air pollution

Answer

C. Increased humidity

Answer

D. Water pollution

Question 50

Which of the following statements about solids is correct?

Accepted Answer

D. Solid particles cannot be easily compressed

Answer

A. Solid particles are less orderly than those of a liquid

Answer

B. Solid have lower densities than liquids

Answer

C. Solid particles have greater kinetic energies than those of liquids

2016 WAEC (WASSCE) Chemistry Past Questions

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