Đáp án:
Giải thích các bước giải:
Câu 3
a) n P=6,2/31=0,2(mol)
n O2=7,84/22,4=0,35(mol)
4P+5O2-->2P2O5
=>O2 dư
n O2=5/4n O2=0,25(mol)
m O2 dư=0,05.32=1,6(g)
b) n P2O5=1/2 n P=0,1(mol)
m P2O5=0,1.142=14,2(g)
câu 4
4P+5O2-->2P2O5
a) n P=7,75/31=0,25(mol)
n O2=5,6/22,4=0,25(mol)
=>P dư
n P=4/5n O2=0,2(mol)
m P dư=0,05.31=1,55(g)
b) n P2O5=2/5n O2=0,1(mol)
m P2O5=0,1.142=14,2(g)
Câu 7
a) CH4+2O2-->CO2+2H2O
b) n CH4=5,6/22,4=0,25(mol)
n CO2=n CH4=0,25(mol)
V CO2=0,25.22,4=5,6(l)
c) n O2=2n CH4=0,5(mol)
V O2=0,5.22,4=11,2(l)
Vkk=5VO2=11,.2.5=56(l)
Câu 8
2CO+O2-->2CO2
2H2+O2--.2H2O
n O2=6,72/22,4=0,3(mol)
n CO2=4,48/22,4=0,2(mol)
n CO=n CO2=0,2(mol)
n O2=1/2n CO2=0,1(mol)
=>n O2(2)=0,3-0,1=0,2(mol)
n H2=2n O2=0,4(mol)
%V CO=0,1/0,5.100%=20%
%V H2=100-20=80%
Câu 9
CH4+2O2-->CO2+2H2O
2H2+O2-->2H2O
n CO2=2,24/22,4=0,1(mol)
n CH4=n CO2=0,1(mol)
n hh=5,6/22,4=0,25(mol)
=>n H2=0,25-0,1=0,15(mol)
%V CH4=0,1/0,25.100%=40%
%V H2=100-40=60%
Câu 10
4Al+3O2-->2Al2O3
1Mg+O2--->2MgO
n O2=3,36/22,4=0,15(mol)
n Al=2,7/27=0,1(mol)
n O2(1)=3/4n Al=0,075(mol)
=>n O2(2)=0,15-0,075=0,075(mol)
=>m Mg =2n O2=0,15(mol)
m Mg=0,15.24=3,6(g)
%m Mg =3,6/3,6+2,7.100%=57,14%
%m Al=100-57,14=42,86%