求化学式量
1）尿素CO(NH2)2 :12+16+(14+2)*2=60
2)氢氧化钠NAOH :23+16+1=40
3)碳酸氢铵NH4HCO3 :14+4+1+12+16*3=79
4)硫酸H2SO4 :2+32+4*16=98
求百分含量
1）CACO3 O%?:16*3/(40+12+16*3)=48%
2）NH4NO3 N%?:14*2/(14+4+14+16*3)=35%
3）(NH4)2SO4 N%?:14*2/(18*2+32+64)=21.2%
4）CH3COOH H%?:1*4/(12+3+12+16*2+1)=6.67%