ilość moli

[biedronka17]

Proszę o pomoc w rozwiązaniu zadania. Oblicz ilość moli wody krystalicznej przypadającej na 1 mol cząsteczek CuSO4

[tlen]

Procedure

1. Take a crystal hydrate.
2. Get mass of hydrate by measuring.
3. Get mass of dehydrated crystal.
4. Determine the formula of the hydrate.


Target and Mass in grams

Crucible
13.55g

Crucible with hydrate
15.84g

hydrate
2.29g

Crucible and dehydrated copper sulfate
14.99g

Dehydrated copper sulfate
1.44g

Water
0.047g




Before we heated copper sulfate, it was blue. Then it turned to white when it was dehydrated.



Calculation
CuSO4 63.55g + 32g + 4*16g = 159.45g

1.44g CuSO4 ( 1 mole CuSO4 / 159.45g CuSO4 ) = 0.009 moles of CuSO4

0.009 moles of CuSO4 ( 6.022*1023 / 1 mole) = 5.42*1021 molecules of CuSO4

H2O 2*1.008g + 16 = 18g

0.85g H2O ( 1 mole H2O / 18g H2O ) = 0.047 moles of H2O

0.047 moles of H2O ( 6.022*1023 molecules of H2O / 1 mole H2O ) = 2.83*1022 molecules H2O

5.42*1021 / 2.83*1022 = 5 (approximately)



Conclusion

Therefore the formula is CuSO4 * 5H2O. There are five water molecules per one copper sulfate.

[biedronka17]

A skąd wzięło się 0,85 g wody? wczesniej bylo napisane że 0,047

[biedronka17]

Już wiem dlaczego)

[tlen]

OK