Răspuns:
7.
MH2=2×1=2g/mol
MH2O=2×1+16=18g/mol
m=n×M=3×2=6g H2
2×2...................2×18g
2H2 + O2 → 2H2O
6g......................xg
x=6×2×18/2×2=calculeaza
8.
MH2O=2×1+16=18g/mol
m=n×M=15×18= 270gH2O
MNa=23g
MNaOH=23+16+1=40g/mol
2×23g.......18g............2×40g
2Na + H2O → 2NaOH + H2↑
xg.............270g............yg
x= 270×2×23/18=calculeaza
y=270×2x40/18=calculeaza
calculam numarul moi de hidrogen ce se degaja
1 mol...........................1mol
2Na + H2O → 2NaOH + H2↑
15moli.........................zmoli
z=15x1/1=15moli H2
9.
MNa=23g/mol
MHCl=1+35,5=36,5g/mol
MH2=2x1=2g/mol
n=m/M
n=146/36,5=4moli HCl
2moli......2moli....................1mol
2Na + 2HCl → 2NaCl +H2↑
xmoli......4moli.....................ymoli
x=4x2/2=4 moliNa
y=4x1/2=2moli H2
caclulam in grame NaCl
2×36,5g....2x40g
2Na + 2HCl → 2NaCl +H2↑
146g..............zg
z=146x2x40/2x36,5=cacluleaza
10.
MH2=2x1=2g/mol
MCl2=2x35,5=71g/mol
MHCl=1+35,5=36,5g/mol
caculam in grame
2g..............................2x36,5g
H2 + Cl2 → 2HCl
25g.................................xg
x=25x2x36,5/2=calculeaza
calculam in moli
n=m/M=25/2=12,5moliH2
1mol...........1mol...........2moli
H2 + Cl2 → 2HCl
12,5moli.....ymoli........z moli
y=12,5x1/1=calculeaza
z=12,5x2/1=calculeaza
11.
2moli........3moli.................................3moli
2Al + 3H2SO4 → Al2(SO4)3 + 3H2↑
3moli.........ymoli................................xmoli
y=3x3/2=calculeaza
x= 3x3/2=calculeaza
calculam in grame
MAl=27g/mol
m=nxM=3×27=81g Al
MAl2(SO4)3=2x27+3x32+12x16=342g/mol
2x27g............................342g
2Al + 3H2SO4 → Al2(SO4)3 + 3H2↑
81g...................................zg
z=81x342/2x27=calculeaza
Explicație:
