electrons.
The number of neutrons is equal to the difference in the mass number and atomic number.
It is equal to $\d
isplaystyle 14-6=8 $.
(ii)(a) The number of neutrons present in 7 mg of C-14 is
6.023×1023×814×7×1010−3=2.4088×1021 neutrons.
(b) Total mass of neutrons in 7 mg of C-14 is 2.4088×1021×1.675×10−274.035×10−6 kg.
(iii)(a)Number of protons present in 1 molecule of ammonia =7+3=10.
Number of molecules present in 34 mg of ammonia is 6.023×1023×34×10−317=1.2044×1021.
Total number of protons present in 34 mg of ammonia=10×1.2044×1021=1.2044×1022
(b) Total mass of protons present in 34 mg of ammonia at STP is 1.6726×10−27×1.204×1022=2.0138×10−5 kg.
When temperature and pressure are changed, there is no difference in the answer.