a) C=md/ms*100 => md=C*ms/100=49*200/100= Calculeaza !!
b) H2SO4 + 2NaOH -> Na2SO4 + 2H2O
98g H2SO4...................2*40g NaOH
98g H2SO4 (md aflat).....x=80g NaOH
md NaOH = 80g
MNaOH=ANa+AO+AH=23+16+1=40g/mol
MH2SO4=2AH+AS+4AO=2*1+32+4*16=98g/mol
c) C=md/ms*100 => ms=md*100/C=80*100/40 = Calculeaza !!
d) 1 mol H2SO4..................1 mol Na2SO4
1 mol H2SO4....................1 mol Na2SO4 (sare)