Question

Calculați numărul de moli și numărul de atomi pentru:

a. 270 g aluminiu;
b. 23 g sodiu/natriu;
c. 112 g fier;
d. 124 g fosfor;
e. 120 g magneziu;
f. 80 g calciu;
g. 260 g zinc;
h. 78 g potasiu;
i. 220 g mangan;
j. 40 g heliu

Va rooog!

Answer 1

Răspuns:

n=nr. moli  ;  m=masa subst.  ( g) ;   M=masa molara(g/moli )

Explicație:

a.

n=m : M

n= 270g : 27g/moli= 10 moli Al

1mol  de atomi de Al------------6,023.10²³atomi Al

10 moli Al------------------------------x

x=10  . 6,023.10²³=60,023 . 10²³ atomi de Al

b.

n= 23g : 23g/moli= 1mol Na

1mol  de atomi de Na------------6,023.10²³atomi de Na

c.

n=112g : 56g/moli=2 moli Fe

1mol de atomi de Fe-----------------6,023.10²³atomi Fe

2moli--------------------------------------------x

x= 2  .  6,023.10²³=12,046 .10²³atomi Fe

d.

n= 124g : 31g/moli= 4moli  fosfor

1mol de atomi de P-------------------6,023.10²³atomi P

4moli --------------------------------------------x

x= 4  . 6,023.10²³=24,092 .10²³atomi fosfor

e.

n=120g : 24g/moli= 5 moli Mg

1mol Mg---------------------6,023.10²³ atomi Mg

5moli--------------------------------x

x= 5  . 6,023.10²³=30,115 .10²³atomi Mg

f.

n= 80g : 40g/moli=2moli Ca

1molCa--------------------6,023.10²³ atomi Ca

2moli--------------------------x

x= 2  . 6,023.10²³=12, 046 .10²³atomi Ca

g.

n=260g : 65g/moli=4moli Zn

1mol Zn-------------------6,023.10²³Zn

4moli----------------------------x

x=4  . 6,023.10²³=24,092.10²³ atomi de Zn

h.

pentru 78 g K lucreaza singur , sa vezi daca ai inteles

i.

n=220g : 55g/moli=4moli Mn

1molMn-----------------6,023.10²³Mn

4moli--------------------------x

x=4 . 6,023.10²³ =24,092.10²³atomi Mn

j.

n= 40g : 4g/moli=10 moli He

1mol  He-----------6,023.10²³He

10 moli------------------------x

x=10 .6,023.10²³= 60,023.10²³atomi He