a) Coeficientul din fata indica 3 moli de NH3,deci
1 mol NH3 contine...................3*NA = 3*6,022*10^23 atomi H
3 moli NH3...................................x atomi H
x=3*3*6,022*10^23 atomi = 5,4198*10^24 atomi H
b) 1 mol H2O......................2*NA = 2*6,022*10^23 atomi H
6 moli H2O..................................x atomi
x=2*6*6,022*10^23 = 72,264*10^23 atomi H
c) 1 mol CH4............................4NA = 4*6,022*10^23 atomi H
10 moli CH4................................x atomi H
x=24,088*10^24 atomi H