Mr(MgCl₂)=24+2х35,5=95
Mr[Cu(OH)₂]=64+2(16+1)= 98
Mr(NaNO₃)=23+14+3x16=23+14+48=85
Mr(Mn₂O₇)=2x55+7x16=110+112=222
Mr(PH₃)=31+3=34
Mr(NH₄OH)=14+4+16+1=35
Mr(H₂SO₄)=2x1+32+4x16=2+32+64=98
Mr(CaCO₃)=40+12+3x16=40+12+48=100
Mr[Al₂(SO₄)₃]=2x27+3(32+4x16)=54+3x96=54+288=342