Question

Find the mass of $3.011\times {10}^{26}$ molecules of $N{H}_3$ in grams.

• A. $8599.81\text{g}$
• B. $8249.81\text{g}$
• C. $8349.81\text{g}$
• D. $8499.81\text{g}$

Answer 1

The correct option is D $8499.81\text{g}$

The molecular mass of $N{H}_3=(14+3\times 1)\text{u}=17\text{u}$
So, mass of one molecule of $N{H}_3=17\text{u}$
Therefore, mass of $3.011\times {10}^{26}$ molecules of $N{H}_3=17\times 3.011\times {10}^{26}$
$=17\times 3.011\times {10}^{26}\times 1.66054\times {10}^{-24}\text{g}$
$=8499.81\text{g}$