Question

How many molecules are present in one gram of hydrogen ($H_2$)?

• A. $6.023\times {10}^{23}$
• B. $6.023\times {10}^{22}$
• C. $3.01\times {10}^{23}$
• D. $3.0125\times {10}^{-12}$

Answer 1

Answer: (C)

$3.01\times {10}^{23}$

Atomic mass of $H$ = $1u$

So, molar mass of $H$ = $1g/mol$

Molar mass of $H_2$ = $2\times 1$ = $2g/mol$

Given mass of $H_2$ = $1g$

No. of moles = $\frac{Mass}{Molarmass}$ = $\frac{1}{2}$ = $0.5$

No. of molecules = $Numberofmoles\times Avogadronumber$ = $0.5\times 6.022\times {10}^{23}$ = $3.01\times {10}^{23}$ molecules