Question

calculate the mass of
1.10^22 atoms of Sulphur
2. 0.2 moles of CO2

Answer 1

1) Molar mass of sulphur = 32 g mol-1
Mass of 6.022× 1023 atoms = 32 g
Mass of 1022 atoms = 326.022×1023×1022 = 0.531 g

2) Molar mass of CO2 = 44 g mol-1
Mass of 1 mole of CO2 = 44 g
Mass of 0.1 mole of CO2 = 44× 0.1 = 4.4 g

Answer 2

2. 1 mol = 6.022*10^23 
     0.2 mol = (6.022*10^23)*0.2
     = 1.2044*10^23