Question

Complete combustion of $3$ $\mathrm{g}$ of ethane gives $\mathrm{x}$ $\times {10}^{22}$ molecules of water. The value of $\mathrm{x}$ is ________. [Round off to the Nearest Integer].

[Use: N_A = $6.023\times {10}^{23}$Atomic masses in u :$\mathrm{C}=12.0;\mathrm{O}=16.0;\mathrm{H}=1.0$]

Answer 1

1. Definition of Combustion:

Combustion is a chemical process in which a substance reacts rapidly with oxygen and gives off heat.

2. The reaction involved in the Combustion of ethane:

${\mathrm{C}}_2{\mathrm{H}}_6+{\mathrm{O}}_2\to 2{\mathrm{CO}}_2+3{\mathrm{H}}_2\mathrm{O}$

3. Calculation:

$1$mole ethane gives $3$ $\mathrm{mol}$ water

So $0.1$ $\mathrm{mol}$ ethane gives $0.3$ $\mathrm{moles}$ water

$0.3moles=0.3\times 6.023\times {10}^{23}$

=$18.069\times {10}^{23}$molecule of water

So, the complete combustion of $3$ g of ethane gives $18$ $\times {10}^{22}$ molecules of water.

The value of $\mathrm{x}$ is $18$.