A container has an unknown quantity of gas at a pressure of 121.6kPa, a volume of 31L and a temperature of 87oC. How many moles of gas are present ?

1.26mol

Explanation:

Using the general gas law equation;

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (K).

Based on the information provided in this question,

P = 121.6kPa = 121.6 × 0.00987atm = 1.2001 atm

V = 31L

T = 87°C = 87 + 273 = 360K

R = 0.0821 Latm/molK

Using PV = nRT

n = PV/RT

n = (1.2001 × 31) ÷ (0.0821 × 360)

n = 37.2031 ÷ 29.556

n = 1.258

n = 1.26mol