2.a
M(CO2)=12+32=44g/mol
wC=12/44*100%=27.3%
wO=100-27.3=72.7%
b)M(CaS)=40+32=72g/mol
wCa=40/72*100%=55.55%
wS=100-55.55=44.45%
v)M(NaNO3)=23+14+48=85g/mol
wNa=23/85*100%=27%
wN=14/85*100%=16.5%
wO=100-27-16.5=56.5%
g) M(Al2O3)=54+48=102g/mol
wAl=54/102*100%=53%
wO=100-53=47%
3.
a) M(NH4Cl)=14+4+35.5=53.5g/mol
wN=14/53.5*100%=26%
b) M((NH4)2SO4)=28+8+32+64=132g/mol
wN=28/132*100%=21%
v) M((NH2)2CO)=28+4+12+16=60g/mol
wN=28/60*100%=46.6%
ответ: в-46.6%