How many grams of CO₂ is present in 0.1 mole of it?

The mass of 5.6 litres of a certain gas at S.T.P. is 12 g. What is the relative molecular mass or molar mass of the gas?

Calculate the number of moles of methane in 0.80 g of methane.

Calculate the weight/mass of :

(a) an atom of oxygen

(b) an atom of hydrogen

(c) a molecule of NH₃

(d) 10²² atoms of carbon

(e) 0.25 gram atom of calcium