When 5 g of calcium is burnt in 2 g of oxygen, then 7 g of calcium oxide is produced. What mass of calcium oxide will be produced when 5 g of calcium is burnt in 20 g of oxygen? Which law of chemical combination will govern your answer?
When 5 gm of calcium is burnt in 2gm of oxygen, then 7 gm of calcium oxide is formed. So, calcium and oxygen combine in the fixed proportion of 5:2 by mass. Now, when 5 gm of calcium is burnt in 20 gm of oxygen, then also 7 gm of calcium oxide will be formed because chemical reactions follows law of constant proportion. As a result, 18 gm of oxygen will be left unreacted.