Question

1.Cati atomi se gasesc in 1.5 moli magneziu?

2.in cati moli de carbon gasesc 12.046x10 la a 22a atomi?

3. cate grame cantaresc 4 moli de heliu?

4.cati moli reprezinta 390g posatiu?

Answer 1

1.

1mol Mg---------------6,023 .10²³ atomi Mg

1,5 moliMg-----------------x

x=1,5 .6,023.10²³  atomi Mg  =9,0345 .10²³atomi Mg

2.

1mol C---------------6,023.10²³atomi C

xmoli-----------------12,046.10²² atomi C

x=12,046 .10²²  : 6,023 .10²³ =0,2 moli C

3.

se apeleaza la rel. : n=m:M   in care n=nr. de moli ; m=masa subst. ;M=masa molara

n=m:M

m=n.M

m=4moli . 4g/moli=16 g He

4.

n=m:M

n=390g : 39g/moli=10 moli K