Question

A 7.50 liter sealed jar at 18 °c contains 0.125 moles of oxygen and 0.125 moles of nitrogen gas. what is the pressure in the container?

Answer 1

Answer: The pressure of the container will be 0.796 atm.

Explanation:

To calculate the mass of bromine gas, we use the ideal gas equation, which is:

PV = nRT

where,

P = pressure of the gas = ? atm

V = Volume of the gas = 7.5 L

n = Number of moles of gas = [0.125 + 0.125] = 0.25 mol

R = Gas constant = $0.0821\text{ L atm }mol^{-1}K^{-1}$

T = temperature of the gas = $18^oC=(273+18)K=291K$

Putting values in above equation, we get:

$P\times 7.5L=0.25mol\times 0.0821\text{ L atm }mol^{-1}K^{-1}\times 291K\\\\P=0.796atm$

Hence, the pressure of the container will be 0.796 atm.

Answer 2

The ideal gas equation is;
PV = nRT; therefore making P the subject we get;
P = nRT/V
The total number of moles is 0.125 + 0.125 = 0.250 moles 
Temperature in kelvin = 273.15 + 18 = 291.15 K
PV = nRT
P = (0.250 × 0.0821 )× 291.15 K ÷ (7.50 L) = 0.796 atm
Thus, the pressure in the container will be 0.796 atm