WAEC Past Questions and Answers - Page 1406

7,026.

Determine the mass of sulphur (IV) oxide obtained when 91.0g of oxygen reacts completely with sulphur according to the following equation: S(s) + O\(_2\)(g) → SO\(_2\)(g) [S = 32; O = 16]

123g

139g

155g

182g

View answer & explanation

Correct answer is D

S + O\(_2\) → SO\(_2\).

According to the equation 32g of O\(_2\) produced 64g of SO\(_2\)

therefore 91g of O2 will produce yg of SO2
y = \(\frac{91 * 64}{32}\)

y = 182g of SO\(_2\)

7,027.

Calculate the mass of chlorine gas which occupies a volume of 1.12 dm\(^3\) a volume of 1.12 dm\(^3\) at s.t.p [Cl = 35.5, 1 mole og gas occupies 22.4 dm\(^3\) at s. t. p ]

1.80g

3.55g

7.10g

15.50g

View answer & explanation

Correct answer is B

1 mole Cl\(_2\) occupy 22.4dm\(^3\)
i.e 2 x 35.5 → 22.4 ; x → 1. 12
:. x = \(\frac{1.12}{22.4}\) x 2 x 35.5 = 3.55

7,028.

What volume of hydrogen will be produced if 100cm³ of ammonia is completely decomposed at constant temperature and pressure? The equation for reaction is 2NH_3(g) → N_2(g) + 3H_2(g)

50cm³

150cm³

200cm³

300cm³

View answer & explanation

Correct answer is B

According to the equation 2NH₃ → N₃ + 3H₂
2 x 22400cm^{3^{of ammonia will produce

3 x 22400cm³ of hydrogen

If 100cm³ of NH₃ is used.

:. H₂ volume = \(\frac{100}{2x22400} x 3x22400

=150cm₃}}

7,029.

The diagram above illustrates a reproductive process in a farm animal. Study it and answer the question.

The parts which protect the foetus from mechanical injury are labelled

I and III

I and II

III and IV

II and III

View answer & explanation

Correct answer is B

The parts which protect the foetus from mechanical injury are labelled I and II.

7,030.

The diagram above illustrates a reproductive process in a farm animal. Study it and answer the question.

The reproductive process illustrated by the diagram is

Lactation

Gestation

Ovulation

Heat

View answer & explanation

Correct answer is B

Gestation refers to the period of pregnancy or the time it takes for female animals, particularly livestock, to carry and develop their offspring before giving birth.