Question

How many litres would 1.00 g of nitrogen gas (N₂) occupy at:

a) STP

b) 84.0°C and 2.15 atm

Answer 1

a)

Molar mass of N2 = 28.02 g/mol


mass(N2)= 1.00 g

number of mol of N2,
n = mass of N2/molar mass of N2
=(1.0 g)/(28.02 g/mol)
= 3.569*10^-2 mol

Given:
P = 1.0 atm
n = 0.035689 mol
T = 273.0 K

use:
P * V = n*R*T
1 atm * V = 0.035689 mol* 0.0821 atm.L/mol.K * 273 K
V = 0.800 L
Answer: 0.800 L

b)

Given:
P = 2.15 atm
n = 0.035689 mol
T = 84.0 oC
= (84.0+273) K
= 357 K

use:
P * V = n*R*T
2.15 atm * V = 0.035689 mol* 0.0821 atm.L/mol.K * 357 K
V = 0.487 L
Answer: 0.487 L