Question

Find the mass of $4.12\times {10}^{24}$ molecules of $N{H}_3$?

• A. $110g$
• B. $116.3g$
• C. $120g$
• D. $100g$

Answer 1

The correct option is B $116.3g$

Number of Moles $=\frac{Givennumberofmolecules}{N_A}$

Number of Moles of $N{H}_3=\frac{4.12\times {10}^{24}}{6.022\times {10}^{23}}=6.84$

Mass of one mole of $N{H}_3=17g\left(molarmass\right)$

Mass of $6.84molesofN{H}_3=6.84\times 17g=116.3g\left(approximately\right)$