Mr(H2SO4)=1×2+32+16×4=98
Mr(H3PO4)=1×3+31+16×4=98
Mr(NaOH)=23+16+1=40
Mr(CaCO3)=40+12+16×3=100
Mr(Al2O3)=27×2+16×3=102
Mr(MgO)=24+16=40
Mr(Na2SO4)=23×2+32+16×4=142
Mr(HNO3)=1+14+16×3=63
Mr(NH3)=14+3=17
Mr(PH3)=31+3=34
