nP= 7,44/31=0,24(mol)

nO2=6,16/22,4=0,275(mol)

PTHH:4 P + 5 O2 -to->2  P2O5

Ta có: 0,24/4 > 0,275/5

=> O2 hết, P dư, tính theo nO2

nP(p.ứ)= 0,275 x 4/5= 0,22(mol)

=>nP(dư)=0,24-0,22=0,02(mol)

=>mP(dư)=0,02.31= 0,62(g)

nP2O5= 2/5 x 0,275= 0,11(mol)

=> mP2O5= 142 x 0,11= 15,62(g)