Question

A mixture of hydrogen and carbon dioxide gases is maintained in a 6.42 L flask at a pressure of 2.97 atm and a temperature of 28 °C. If the gas mixture contains 1.02 grams of hydrogen, the number of grams of carbon dioxide in the mixture is _____ g

Answer 1

Step 1: calculate total number of moles
Given:
P = 2.97 atm
V = 6.42 L
T = 28.0 oC
= (28.0+273) K
= 301 K

find number of moles using:
P * V = n*R*T
2.97 atm * 6.42 L = n * 0.08206 atm.L/mol.K * 301 K
n = 0.772 mol

Step 2: calculate mol of H2

Molar mass of H2 = 2.016 g/mol


mass(H2)= 1.02 g

use:
number of mol of H2,
n = mass of H2/molar mass of H2
=(1.02 g)/(2.016 g/mol)
= 0.506 mol

Step 3: calculate mol of CO2
Use:
Mol of CO2 = total mol - mol of H2
= 0.772 mol - 0.506 mol
= 0.266 mol

Step 4: calculate mass of CO2

Molar mass of CO2,
MM = 1*MM(C) + 2*MM(O)
= 1*12.01 + 2*16.0
= 44.01 g/mol

use:
mass of CO2,
m = number of mol * molar mass
= 0.266 mol * 44.01 g/mol
= 11.71 g
Answer: 11.7 g