JAMB Chemistry Past Questions & Answers

1,566.

A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that?

collisions are perfectly elastic

forces of repulsion exist

forces of repulsion are in equilibrium

collision are inelastic

View answer & explanation

Correct answer is A

Collisions between gas particles or collisions with the walls of the container are perfectly elastic. None of the energy of a gas particle is lost when it collides with another particle or with the walls of the container.

1,567.

Equal volumes of CO,SO2, NO2 and H2S were released into a room at the same point and time. Which of the following gives the order of diffusion of the gases to the opposite corner of the room?
(S = 32, C = 12, O = 16, N = 14, H = 1)

CO, SO₂,NO₂,H₂S

SO₂,NO₂,H₂S,CO

CO,H₂S,SO₂,NO₂

CO,H₂S,NO₂,SO₂

View answer & explanation

Correct answer is D

- At a constant temperature and pressure, the rate lof diffusion of a gas is inversely proportional to the rate of its relative molecular mass.

- The higher the RMM of a gas the Lower the rate of diffusion and vice versa

- Hence; CO,H2S,NO2,SO2 will be the order of diffusion.

1,568.

The volume occupies by 1.58g of a gas at s.t.p is 500cm³. What is the relative molecular mass of the gas?

(G.M.V at s.t.p = 22.40dm³)

View answer & explanation

Correct answer is D

500cm³ = 1.58g

=22400cm = (1.58g)/(500cm³) χ 22400cm³) = 70.78 g
= 71g

1,569.

If a gas occupies a container of volume 146 cm³ at 18°C and 0.97`atm, its volume 146cm³ at s.t.p is?

133

146

266

292

View answer & explanation

Correct answer is A

V₁ = 146cm³ T₁ = 273 + 118 = 291 k

P₁ = 0.971 atmosphere

V₂ = ? T₂ = 273K P₂ = 1 atom

V₂ = (0.971 atom χ 146cm³ χ 273k)/(1atm χ 291k) = 132997 0r = 133cm³