Answer to Question #184790 in Chemistry for Zainab

Question

what volume does 81.2 of CH4 occupy at 5.5° celcius and 31 kPa

Answer 1

P = 31 kPa

V = unknown

R = 8.314 L kPa mol^-1 K^-1

T = 5.5°C = 278.5 K

m(CH₄) = 81.2 g

Solution:

The molar mass of CH₄ is 16 g/mol.

Hence,

Moles of CH₄ = (81.2 g CH₄) × (1 mol CH₄ / 16 g CH₄) = 5.075 mol

n(CH₄) = 5.075 mol

In order to solve this problem we would use the Ideal Gas Law formula:

PV = nRT

Divide to isolate V:

V = nRT / P

Plug in the numbers and solve for V:

V = (5.075 mol × 8.314 L kPa mol^-1 K^-1 × 278.5 K) / (31 kPa) = 379.06 L = 379 L

V = 379 L

Answer: V = 379 L