Question

When 3.0g of carbon is burnt in 8.00g oxygen, 11.00g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00g of carbon is burnt in 50g of oxygen? Which law of chemical combination will govern your answer?

Answer 1

C + O₂ → CO₂

3 g 8 g 11 g

Total mass of reactants = mass of C + mass of O = 3+8=11g
Total mass of reactants = total mass of products
Hence, the law of conservation of mass is proved.
Further, it also shows carbon dioxide contains carbon and oxygen in a fixed ratio by mass, which is 3 : 8. Thus it also proves the law of constant proportions. 3g of carbon must also combine with 8 g of oxygen only. This mean that (50 – 8) = 42 g of oxygen will remain unreacted.