3g of hydrogen react with 30g of oxygen to yield H₂O

a) which is the limiting reactant?

b) which is the exess reactant?

c) calculate the maximum amount of H₂O that can be formed?

d) calculate the amount of reactant which is unreacted?

The balanced chemical equation for reaction of water and oxygen is written as

2H₂ + O₂→ 2H₂O

According to the balanced chemical equation;

(2x2)= 4g of Hydrogen reacts with 32g of Oxygen.

So, 3g of Hydrogen will react with (3x32) / 4 = 24g of Oxygen.

Since, the amount of Oxygen given (30g) is more than the required amount of Oxygen (24g). Thus, oxygen is the excess reagent and hydrogen is the limiting reagent. The amount of water formed will depend upon the amount of Hydrogen.

4g of Hydrogen produces (2x18) g of water.

So, 3g of Hydrogen produces (2x18x3) / 4 = 27g of water

The amount of Oxygen left unreacted = 30g - 24g = 6g