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DAU 100 PCTE!
1. Calculati masele molecular pentru urmatoarele substante:
Zn(OH)2; CaO; NaNO3; Mg3(PO4)2
Mase atomice: AZn = 65; AO = 16 ; AH = 1; ACa = 40; ANa = 23; AN = 14; AMg = 24; AP = 31.
2. Calculati nr de moli care se gasesc in 222 g Ca(OH)2?

3. Calculati nr de molecule care se gasesc in 3 moli Mg(OH)2


Răspuns :

Răspuns:

Explicație:

1.

MZn(OH)2= 65 + 2.16 +2=99-------> 99g/moli

M CaO = 40 +16=56------> 56g/moli

M NaNO3= 23 + 14 + 3.16=85-------> 85g/moli

MMg3(PO4)2 = 3.24 + 2.31 + 8.16=262------> 262g/moli

2.

MCa(OH)2= 40 +2.16 +2=74-------> 74g/moli

n= m : M

n= 222g : 74g/moli= 3moli Ca(OH)2

3.

3moli Mg(OH)2

nr. molecule

M=24 + 2.16 +2=58-------> 58g/moli

1mol Mg(OH)2---------6,023.10²³ molecule

3moli----------------------------x

x= 3  .  6,023.10²³=18,069 .1`0²³molecule  Mg(OH)2