Question

Determina numarul de electroni, respectiv neutroni din : a) 1 mol sodiu;b) 1,4g litiu;c) 4kg calciu;d) 5kmol heliu.

Answer 1

23g Na -------1mol Na-------11 . 6,023 .10²³ e-------12 . 6,023 .10²³ n

b.

se afla nr . de moli de  Li

n=m:M= 1,4 g : 7g/mol

           =0,2 moli Li

1mol Li----------3 . 6,023 .10²³ e------------4 . 6,023 .10²³ n

0,2 moli-----------------x------------------------------y

x=0,2 .3 . 6,023 .10²³ e =

y= 0,2 . 4 .6,023 .10²³ n =

c.

4kg=4000g Ca

n= 4000g : 40g/moli=100moli Ca

1moli Ca -----------20 .6,023 .10²³ e-------------20. 6,023 .10²³ n

100 moli ----------------x-----------------------------------y

x=100. 20 .6,023.10²³ e =

y= 100. 20 .6,023 .10²³ n=

d.

5kmoli=5000 moli

1mol He---------2. 6,023 .10²³ e--------------2. 6,023.10²³ n

5000 moli He--------------x-------------------------------y

x=5000 . 2 .6,023 .10 ²³ e=

y=5000.2.6,023.10²³ n =