11) 6 x 10²⁰ molecules of SO₂ are removed from 320 mg of SO₂. What are the remaining moles of SO₂?

12) Calculate the weight of lime obtained by heating 200 kg of 90% pure limestone:

13) Decomposition of potassium chlorate gives potassium chloride and oxygen. If 4.2 moles of oxygen is needed for an experiment, how many grams of KClO₃ must be decomposed?

14) A gaseous alkane is exploded with oxygen. The volume of O₂ for complete combustion to CO₂ formed, is in the ratio 7 : 4. Deduce molecular formula of alkane.

15) 10 moles SO₂ and 15 moles O₂ were allowed to react over a suitable catalyst. 8 moles of SO₃ were formed. The remaining moles of SO₂ and O₂ are respectively: