Question

Calculate the number of moles of methane in $0.80g$ of methane.

Answer 1

Step 1:

Weight of methane $\left({\mathrm{CH}}_4\right)$=$8\mathrm{g}$

The molecular weight of methane is:-

The atomic mass of hydrogen=$1\mathrm{u}$

In methane, there are $4$ atoms of hydrogens. So, $1\mathrm{u}\times 4$=$4\mathrm{u}$

The atomic mass of carbon=$12\mathrm{u}$

So, the molecular mass of $\left({\mathrm{CH}}_4\right)$=$\mathrm{C}+{\mathrm{H}}_4$

=$12+4$=$16\mathrm{u}$

Step 2: $\mathrm{Number}\mathrm{of}\mathrm{moles}=\frac{\mathrm{Weight}}{\mathrm{Molecular}\mathrm{mass}}$

Step 3: $$\begin{gathered} \mathrm{Moles}=\frac{0.8}{16} \\ =0.05\mathrm{moles} \end{gathered}$$

Hence, the number of moles of methane in 0.80 g is 0.05 moles.