question_answer 16)

When 3.0 g of carbon is burnt in 8.00 g 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?  

Answer:

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. 3 g of carbon must also combine with 8 g of oxygen only. This mean that (50 - 8) = 42 g of oxygen will remain unreacted.