Question

de la 12 ( inclusiv) până la 20

Answer 1

12.
24g.......x moli
2 Ca + O2-->2CaO
2×40.....1
m pură=m totală×puritate
m pură=120×20/100=24g
MCa=ACa=40 g/mol
x=24/(2×40)=0,3 moli

13.
60g..........................x
CaCO3--> Ca+ CO2
100........................22,4
m pură=m totală×puritate
m pură=100×60/100=60g
MCaCO3=ACa+AC+3AO
MCaCO3=40+12+3×16=100g/mol
x=22,4×60/100=13,44 l

14.
x....96g
Fe+S-->FeS
1.....32
puritate=100-25=75%
m pură=m totală × puritate
m pură=128×75/100=96g
Ms=As=32g/mol
x=96/32=3 moli

15.
93g........................x
4P + 5O2-->2P2O5
4×31...................2
puritate=100-25=75%
m pură=m totală × puritate
m pură =124×75/100=93g
Mp=Ap=31 g/mol
x=(93×2)/(4/31)=1,5 moli

16.
109,5........x
2HCl + 2Na-->3NaCl+H2
2×36,5...2×23
c=md/ms×100
md=c×ms/100=75×146/100=109,5g
MHCl=AH+ACl=1+35,5=36,5 g/mol
MNa=ANa=23g/mol
x=(109,5×2×23)/(2×36,5)=69g

17.
147g...................x
H2SO4+ Ca(OH)2-->CaSO4+2H2O
98..................74
c=md×100/ms
md=c×ms/100=75×196/100=147g
MH2SO4=2Ah+As+4Ao
MH2SO4=2+32+4×16=98g/mol
MCa(OH)2=ACa+2AO+2AH
MCa(OH)2=40+2×16+2=74g/mol
x=74×147/98=111g
c=md×100/ms
ms=md×100/c=111×100/40=277,5 g

18.
x...........640g.......................y
Fe + CuSO4-->FeSO4+Cu
50.........160..........................64
c=md×100/ms
md=c×ms/100=80×800/100=640g
MFe=AFe=50g/mol
MCuSO4=ACu+AS+4AO
MCuSO4=64+32+4×16=160g/mol
MCu=ACu=64 g/mol
x=640×50/160=200g
a)m cui=200×100/70=385,71g
b)y=64×640/160=256g

19.
y............3
Zn+2HCl-->ZnCl2+H2
65.......2
1mol.............6,022×10^23 molecule
x moli..........18,069×10^23 molecule
x=(18,069×10^23)/(6,022×10^23)=3 moli
MZn=AZn=65g/mol
y=3×65/2=97,5 g

20.
...x........................0,2moli
2HgO-> 2Hg + O2
2×217....................1
MHgO=AHg+AO=201+16=217g/mol
x=2×0,2×217=86,8g
puritate=m pură/m totală×100
puritate=86,8/108,5×100=80%