Mr(N₂) =14·2 =28
Mr(Fe₂O₃) = 56·2+16·3= 160
Mr(Ca(OH)₂)= 40+16·2+1·2= 74
Mr(Al₂(SO₃)₃)=27·2+(32+16·3)·3=294
Mr(CuSO₄·5H₂O) = 64+32+16·4 + 5(1·2+16) =250
Mr(N₂) =14·2 =28
Mr(Fe₂O₃) = 56·2+16·3= 160
Mr(Ca(OH)₂)= 40+16·2+1·2= 74
Mr(Al₂(SO₃)₃)=27·2+(32+16·3)·3=294
Mr(CuSO₄·5H₂O) = 64+32+16·4 + 5(1·2+16) =250