# Chemistry Past Questions

Exam Body:

Correct answers are highlighted in green.

### Question 1

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

### Options

A) Activation energy

B) Bond energy

C) Kinetic energy

D) Potential energy

Exam Body: WAEC

### Explanation:

When reactant particles collide, they must posses a minimum amount of energy for effective collisions to take place. This minimum energy is called activation energy, and it is the energy possessed by reactant particles for products to be formed.

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### Question 2

The bond formed between $$H_2O$$ and $$H^+$$ to form the hydroxonium $$H_3O^+$$ is

### Options

A) Dative

B) Covalent

C) Electrovalent

D) Ionic

Exam Body: WAEC

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### Question 3

An element $$X$$ froms the following oxides $$X_2O, XO$$ and $$XO_2.$$ This phenomenon illustrates the law of ________?

### Options

A) Conservation of mass

B) Definite proportion

C) Mass action

D) Multiple proportion

Exam Body: WAEC

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### Question 4

How many moles of oxygen would contain $$1.204 \times 10^{24}$$ molecules?
NB: Avogadro's constant (NA) $$= 6.02 \times 10^{23}$$

A) 1

B) 2

C) 3

D) 4

Exam Body: WAEC

### Explanation:

$$6.02 \times 10^{23}$$ molecules is $$1$$ mole
$$1.204 \times 10^{24}$$ molecules will be:
$$\frac{1.204 \times 10^24 \times 1}{6.02 \times 10^23}$$
$$\frac{1.204 \times 10}{6.02}$$ $$= \frac{12.04}{6.02} = 2$$ moles

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### Question 5

Which of the following statements about solids is correct?

### Options

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

B) Solid have lower densities than liquids

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

D) Solid particles cannot be easily compressed

Exam Body: WAEC

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### Question 6

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

### Options

A) Beaker

C) Measuring cyclinder

D) Pipette

Exam Body: WAEC

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### Question 7

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

### Options

A) Boyle's and Charles' laws

B) Boyle's and Graham's laws

C) Charles' and Graham's laws

D) Dalton's and Graham's laws

Exam Body: WAEC

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### Question 8

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

### Options

A) Brownian motion

B) Diffusion

C) Osmosis

Exam Body: WAEC

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### Question 9

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

### Options

A) They are both gases

B) Their molecules contain carbon

C) They have the same relative molecular mass

D) Both are denser than air

Exam Body: WAEC

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### Question 10

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

### Options

A) Atomization

B) Electronegativity

C) Electron affinity

D) Ionization

Exam Body: WAEC

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### Question 11

An aqueous solution of (NH4)2 SO4 is

### Options

A) Acidic

B) Alkaline

C) Amphoteric

D) Neutral

Exam Body: WAEC

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### Question 12

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

### Options

A) The process is endothermic

B) The process is exothermic

C) NH4Cl forms a saturated solution

D) NH4Cl is highly soluble in water

Exam Body: WAEC

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