When 3.0 g of carbon is 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?

The reaction of the burning of carbon in oxygen may be written as:

$C + O_2 \rightarrow CO_2$

(1 mole of carbon)+ (Oxygen 1 mole)(carbon dioxide) 

3g + 8g → 11g

The total mass of reactants = mass of carbon + mass of oxygen

=3g+8g

=11g

The total mass of reactants = Total mass of products

Therefore, the law of conservation of mass is proved.

It also depicts that the carbon dioxide contains carbon and oxygen in a fixed ratio by mass, which is 3:8.

3 g of carbon must also combine with 8 g of oxygen only.

This means that (50−8)=42g of oxygen will remain unreacted.

The remaining 42 g of oxygen will be left un-reactive. In this case also, only 11 g of carbon dioxide will be formed

The answer governs the law of constant proportion.