Question

what mass of carbon is contained in 1.64 g of carbon dioxide

Answer 1

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


mass(CO2)= 1.64 g

use:
number of mol of CO2,
n = mass of CO2/molar mass of CO2
=(1.64 g)/(44.01 g/mol)
= 3.726*10^-2 mol
This is number of moles of CO2

one mole of CO2 contains 1 moles of C
use:
number of moles of C = 1 * number of moles of CO2
= 1 * 3.726*10^-2
= 3.726*10^-2

Molar mass of C = 12.01 g/mol

use:
mass of C,
m = number of mol * molar mass
= 3.726*10^-2 mol * 12.01 g/mol
= 0.447 g
Answer: 0.447 g