Calculate the mass of $1\times {10}^{23}$ molecules of methane.

$$\begin{gathered} \mathrm{molecular}\mathrm{mass}\mathrm{of}{\mathrm{CH}}_4\mathrm{is}=16 \\ \mathrm{Mass}\mathrm{of}6.022\times {10}^{23}\mathrm{molecules}\mathrm{of}\mathrm{methane}=16\mathrm{grams}. \\ \mathrm{Mass}\mathrm{of}1\times {10}^{23}\mathrm{molecules}\mathrm{of}\mathrm{methane}=\frac{16}{6.022}=2.657\mathrm{grams}. \end{gathered}$$