When 3.0 g of carbon in burnt in 8.00 g of oxygen, 11.00 g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen? Which law of chemical combination will govern your answer?

Our answer will be governed by the law of constant proportions. Now, since carbon and oxygn combine in the fixed proportion of 3 : 8 by mass to produce 11 g of carbon dioxide, therefore, the same mass of carbon dioxide (11 g) will be obtained even if we burn 3 g of carbon in 50 g of oxygen. The extra oxygen (50 – 8 = 42 g oxygen) will remain unreacted.