JAMB Chemistry Past Questions & Answers - Page 260

1,296.

constituent particles acquires a greater kinetic energy

energy of vibration of particles of the solid is less than the intermolecular forces

constituent particles acquires energy above the average kinetic energy

energy of vibration of particles of the solid equals the intermolecular forces

Correct answer is D

When a solid is heated, the particles are given more energy and start to vibrate faster. At a certain temperature, the particles vibrate so much that their ordered structure breaks down. At this point the solid melts into liquid.

1,297.

If sulphur (IV) oxide and methane are released simultaneously at the opposite ends of a narrow tube, the rates of diffusion Rso2 and Rch4 will be in the ratio?

(S = 32, O = 16, C = 12, H = 1)

4:1

2:1

1:2

1:4

View answer & explanation

Correct answer is C

No explanation has been provided for this answer.

1,298.

30cm³ of hydrogen was collected over water at 27°C and 780 mm Hg. If the vapour pressure of water at the temperature of the experiment was 10 mm Hg, calculate the volume of the gas at 760 mm Hg and 7°C?

40.0 cm³

35.7 cm³

28.4 cm³

25.2 cm³

View answer & explanation

Correct answer is C

Y₁ = 30cm³ T₁ = 27 + 273 = 300K and P₁ = (780 - 10)mm Hg i.e the pressure minus the vapour pressure of water
P₂ = 760mm Hg and T₂ = 7 + 273 = 280K
From (P₂V₂) / (T₂) = (P₁V₁) / (T₁)
(770 x 30) / (300) = (760 x O₂) / (280)
V₂ = (770 x 30x 280) / (300 x 760)
V₂ = 28.4 cm³

1,299.

C₃H_8(g) + 50_2(g) → 4H₂O + 3CO_2(g). Form the equation above the volume of oxygen at s.t.p. required to burn 50cm³ of propane is?

250 cm³

150 cm³

100 cm ³

50 cm³

View answer & explanation

Correct answer is A

C₃H₈ + 50₂ → 4H₂O + 3CO₂.
From the equation above 1 dm³ of C₃H₈ require 5dm³ of O₂ at s.t.p.
∴ 50cm³ of C₃H₈ require x = (50) / (1000) x 5 x 1
x = (250) / (1000)
x = 250cm