Question

Find:

(a) the total number protons

(b) the total mass of protons in 34 mg of ${NH}_3$ at STP.

Will the answer change if the temperature and pressure are changed?

Answer 1

(a)Number of protons present in 1 molecule of ammonia $=7+3=10$.

Number of molecules present in 34 mg of ammonia is $\frac{6.023\times {10}^{23}\times 34\times {10}^{-3}}{17}=1.2044\times {10}^{21}$.

Total number of protons present in 34mg of ammonia$=10\times 1.2044\times {10}^{21}=1.2044\times {10}^{22}$.

(b) Total mass of protons present in 34 mg of ammonia at STP is:

$1.6726\times {10}^{-27}\times 1.204\times {10}^{22}=2.0138\times {10}^{-5}$ kg.

When temperature and pressure are changed, there is no difference in the answer.