a) MCaO=56g/mol
MCa(OH)2=74g/mol
CaO + H2O = Ca(OH)2
n=m/M=5,6/56=0,1 moli CaO = nCa(OH)2
mCa(OH)2=74*0,1=7,4g Ca(OH)2
b) MP2O5=142g/mol
MH3PO4=98g/mol
142g.....................98g
P2O5 + 3H2O = 2H3PO4
24,2g..................x=16,7g
n=m/M=16,7/98=0,17 moli H3PO4