Question

Mass of 4.82 x ${10}^{25}$ molecules of $H_{2}O$ is approximately ____.

• A. 1440 g
• B. 1280 g
• C. 160 g
• D. 1600 g

Answer 1

The correct option is A 1440 g

Given that, there are $4.82\times {10}^{25}$ molecules of water.

Number of moles of water $=\frac{\text{Total number of molecules}}{\text{Avogadro constant}}=\frac{4.82\times {10}^{25}}{6.022\times {10}^{23}}=80.04$

Therefore, mass of water = $\text{Number of moles}\times \text{Molar Mass}$
$=80.04\times 18=1440.72$ g