# For the following reaction : 2 H_2 + O_2 rightarrow 2 H_2O. (a) How many moles of water are...

## Question:

For the following reaction :

{eq}2 H_2 + O_2 \longrightarrow 2 H_2O. {/eq}

(a) How many moles of water are produced from the combustion of {eq}3.5 \ mol {/eq} of hydrogen and {eq}5.2 \ mol {/eq} of oxygen ?

## Moles of Product:

In a chemical reaction reactant(s) forms product(s).The moles of product formed depend on the moles of limiting reactant present in the reaction mixture. The limiting reactant completely reacted in the reaction.

First, identify the limiting reactant in this reaction mixture.

Moles of oxygen (O2) =5.2 mol

Moles of hydrogen = 3.5 mol

• The limiting reactant completely reacted in the chemical reaction.
• From the balanced equation--

2 mol hydrogen reacts with 1 mol oxygen.

So,3.5 mol hydrogen reacts with (1/2)*3.5 mol = 1.75 mol Oxygen.

• Remaining hydrogen = (taken-reacted) = (3.5-3.5)mol = 0 mol.i.e. completely reacted.
• Remaining oxygen = (taken-reacted) = (5.2-1.75)mol = 3.45 mol

Hence,Hydrogen is the limiting reactant.

• From the balanced equation--

2 mol of hydrogen produces 2 mol water.

So,3.5 mol hydrogen produces 3.5 mol water.

Therefore,3.5 mol water is produced from the combustion of {eq}3.5 \ mol {/eq} of hydrogen and {eq}5.2 \ mol {/eq} of oxygen. 