a) Ca(OH)₂ este hidroxidul de calciu
Prima data calculezi masa Ca(OH)₂ =40+2·16+2·1=40+32+2=74 g
1 mol Ca(OH)₂ ........... 74 g Ca(OH)₂
5 moli Ca(OH)₂............ x
x=5·74=370 g Ca(OH)₂
b)14 g N ......... 6,023·10²³
y .................72,264·10²³
y=14·72,264·10²³/6,023·10²³
y=167,97 g N
c) Masa NH₃=17 g
1 mol........17 g
z................255 g
z=255/17=15 moli NH₃
d)1 mol........6,023·10²³
w.............123,484·10²³
w=123,484·10²³/6,023·10²³=20,502 moli