Question

Methane molecule is a compound consisting of carbon and hydrogen in the ratio 1:4 if in a sample of methane there are 1000 molecules of hydrogen, how many molecules of carbon are there

Answer 1

$$\begin{gathered} \mathrm{Ratio}\mathrm{of}\frac{\mathrm{carbon}}{{\mathrm{hydrogen}}_{}}\mathrm{molecules}=\frac{1}{4}. \\ \mathrm{Let}\mathrm{there}\mathrm{be}4x\mathrm{molecules}\mathrm{of}\mathrm{hydrogen},\mathrm{so}\mathrm{molecules}\mathrm{of}\mathrm{carbon}\mathrm{will}\mathrm{be}x. \\ \Rightarrow 4x=4000 \\ \Rightarrow x=1000 \\ \mathrm{Therefore},\mathrm{there}\mathrm{are}1000\mathrm{molecules}\mathrm{of}\mathrm{carbon}. \end{gathered}$$