To start off any questions, we write down the givens.
Mass CO2 = 168.2g
Molar Mass CO2 = 44.011g/mol
Moles CO2 = ?
To find the number of moles, we do mass/molar mass to find the # moles
n CO2 = 44.011g / 168.2 g/mol
n CO2 = 0.26165874 mol
n CO2 = 0.2617 mol
The number of moles in the sample is 0.2617 mol.
