a.
36g H2O
g H
-se afla masa molara
MH2O=2+16=18------> 18g/moli
- se cunoaste ca in 18g H2O se afla 2 g hidrogen
- se va afla cate g de H sunt in 36g H2O
18g H2O-----------2g H
36g H2O------------xg
x=36 . 2 : 18 =4 g H
b.
MNH3=14 + 3 = 17 -------> 17g/moli NH3
17g NH3---------------3 g H
3400g-------------------x
x=3400 . 3 : 17=600 g H = 0,6 kg H
c.
- se afla molii de HCl
1mol HCl---------6,023 .10²³ molecule HCl
x moli -------------6,023 .10²² molecule HCl
x=6,023.10²² : 6,023.10²³=0,1 moli HCl
- se afla masa de HCl
n=m:M
m=n.M
m=0,1 moli . 36,5 g/moli=3,65 gHCl
- se afla masa molara a HCl
M=1+ 35,5 =36,5 -----> 36,5 g/moli
-se afla masa de H din 3,65 g HCl
36,5 g HCl---------1g H
3,65 g------------------y
y=3,65 .1 ; 36,5=0,1 g H
d.
2 moli NaOH
M=23+16+1=40------->40g/moli
m=n.M
m=2moli. 40g/moli=80g NaOH
40g NaOH-----------1 g H
80gNaOH ------------xgH
x=80: 40=2 g H
e.
0,1 kmoli H2SO4=100 moli
M= 2+32 + 4.16=98 ------> 98g/moli
m=n.M=100moli .98g/moli=9800 g H2SO4
98 g H2SO4-----------2gH
9800 g--------------------x
x=9800.2 : 98=200g H
