Water is 11.2% by mass hydrogen (H). How many kilograms of water would contain 4.8 g of hydrogen?

Jan 25, 2016

If there are 4.8 g of hydrogen in an unspecified quantity of water, there are $\frac{4.8 \cdot g}{1.00794 \cdot g \cdot m o {l}^{-} 1}$ $=$ $4.76$ $m o l$ $H$.
Given the composition of water, ${H}_{2} O$, there are thus $2.38$ $m o l$ water.
Thus, mass of water $=$ $2.38$ $m o l$ $\times$ $18.01$ $g \cdot m o {l}^{-} 1 \times {10}^{-} 3 \cdot k g \cdot {g}^{-} 1$ $=$ ?? $k g$