Answer to Question #347374 in General Chemistry for Abdulrafiu

Question

If 465cm³ of SO2 can diffused through a porous partition in 30secs , how long will 620cm³ of hydrogen sulphide take to diffuse through the same (H=1,S=32,O=16)

Answer 1

Solution:

Graham's law states that the rate of diffusion or of effusion of a gas is inversely proportional to the square root of its molecular weight.

Graham's Law can be expressed as:

rate ∝ 1 / (molecular weight)^1/2

Therefore,

(r₁ / r₂) = (M₂ / M₁)^1/2

r₁ = rate diffusion of SO₂ = (465 cm³) / (30 s) = 15.5 cm³ s⁻¹

r₂ = rate diffusion of hydrogen sulphide (H₂S) = 620 cm³ / t

M₁ = molecular weight of SO₂ = 32 + 2×16 = 64 g mol⁻¹

M₂ = molecular weight of H₂S = 2×1 + 32 = 34 g mol⁻¹

Thus:

(15.5 / r₂) = (34 / 64)^1/2

15.5 / r₂ = 0.729

r₂ = 21.26 cm³ s⁻¹

r₂ = 21.26 cm³ s⁻¹ = 620 cm³ / t

t = 29.16 s

Answer: 29.16 seconds