Question

What is the mass, in grams, of 0.125 L of CO2 at STP? Question 4 options: 2.80 g 181 g 0.246 g 4.11 g

Answer 1

1) Use the fact that 1 mol of gas at STP occupies 22.4 liter

=> 1 mol / 22.4 l = x / 0.125 l => x = 0.125 l * 1 mol / 22.4 l = 0.00558 mol

2) Now use the molar mass of the gas

molar mass of CO2 ≈ 44 g / mol

Formula: molar mass = mass in grams / number of moles =>

mass in grams = molar mass * number of moles = 44 g/mol * 0.00558 moles

mass = 0.246 g

Answer: 0.246 g