H2NCH2CH2COOH+CH3OH-(H2SO4)->H2NCH2CH2COOCH3+H2O
8Al + 27HNO3 -> 8Al(NO3)3 + 3NH3 + 9H2O
Al(0) -3ё -> Al(+3) - в скобках с.о.
N(+5) +8ё -> N(-3)
2NaOH+H2SO4=Na2SO4+2H2O
Na2CO3+H2SO4=Na2SO$+H2O+CO2
2CO2+Ca(OH)2=Ca(HCO3)2
пусть CO2 -X,а Ca(HCO3)2 =5г => CO2=2,71г
если CO2=2,71г, => Na2CO3 =3,26г
если Na2CO3 =3,26г => NaOH=10,87г
W(NaOH)=21,5%
W(Na2CO3)= 12,7%
2P+3O2=P2O3
2Ca+O2=2CaO
2Ba+O2=2BaO
2N+3O2=N2O3