Question

Mass of 1 atom of Hydrogen is _____

• A. 1.66 $\times$ ${10}^{-24}$ g
• B. 1.67 $\times$ ${10}^{-20}$ g
• C. 6.022 $\times$ ${10}^{-23}$ g
• D. 6.022 $\times$ ${10}^{-20}$ g

Answer 1

The correct option is A

1.66 $\times$ ${10}^{-24}$ g

Molar mass is mass of 1 mole of that substance.

$\therefore 6.022\times {10}^{23}\times H$ atoms $=1g$
$\therefore 1H$ atoms $=xg$
By unitary method (cross multiplication)$\Rightarrow 1\times 1=x\times 6.022\times {10}^{23}\Rightarrow x=\frac{1}{6.022\times {10}^{23}}\Rightarrow x=0.166\times {10}^{-23}\Rightarrow x=1.66\times {10}^{-24}g$