Q1. Calculate the number of moles of each substance in samples with the following masses:
a) 2.4 g of He
b) 250 mg of Carbon
c) 15 g of sodium Chloride
d) 40 g of Sulphur

Q2. Calculate the mass in grams of each of the following samples:
a) 1.2 moles of K
b) 75 moles of H2
c) o.25 moles of steam
d) 0.15 mole of Cuso4