Water of crystallisation

HideShow resource information
  • Created by: racheon
  • Created on: 03-03-14 11:41
Define hydrated.
A crystalline compound containing water molecules.
1 of 17
Define anhydrous.
A substance that contains no water molecules.
2 of 17
Define water of crystallisation.
Water molecules that form an essential part of the crystalline structure of a compound.
3 of 17
How is the empirical formula of the compound separated from the water of crystallisation?
By a dot.
4 of 17
Hydrated copper sulfate has 5 H2O molecules for each unit of CuSO4. What is it's empirical formula?
CuSO4.5H2O.
5 of 17
What is the empirical formula of colbat chloride hexahydrate?
CoCl2.6H2O.
6 of 17
What is the empirical forumla of sodium sulfate decahydrate?
Na2SO4.10H2O.
7 of 17
What do you use to work out the formula of a hydrate salt?
Percentage or mass compositions.
8 of 17
What method do you use to work out the formula of a hydrate salt?
The same method you would use for empirical formula, but adding an extra step for the dot formula.
9 of 17
What element do you use to work out how many water molecules you have?
Hydrogen.
10 of 17
If you have any extra oxygen atoms after working out the dot formula, what do they belong to?
The substance.
11 of 17
The empirical formula of hydrated magnesium chloride is MgCl2H10O5. What is it's dot formula?
MgCl2.5H2O.
12 of 17
The empirical formula of hydrated sodium carbonate is Na2CH20O13. What is it's dot formula?
NaCO3.10H2O.
13 of 17
The empirical formula of hydrated calcium nitrate is CaN2H8O10. What is it's dot formula?
Ca(NO3)2.4H2O.
14 of 17
How do you determine the formula of a hyrdrated salt?
1. Heat it so the water evaporates. 2. You need the mass of the hydrated salt, the anhydrous salt and the water lost.
15 of 17
The mass of MgSO4.xH2O is 4.312g. The mass of MgSO4 is 2.107g. The mass of H2O is 2.205g. What is x?
1. Calculate the amount, in mol, of MgSO4: M(MgSO2)=24.3+32.1+(16x4)=120.4g mol^-1. n(MgSO4)=2.107/120.4=0.0175mol. 2. Calculate the amount, in mol, of water: 2.205/18=0.1225. 3. Determine the formula of the hydrated salt: 0.0175:0.01225=1:7. x=7.
16 of 17
How do you work out the amount, in moles, when talking about mass?
n=m/M.
17 of 17

Other cards in this set

Card 2

Front

Define anhydrous.

Back

A substance that contains no water molecules.

Card 3

Front

Define water of crystallisation.

Back

Preview of the front of card 3

Card 4

Front

How is the empirical formula of the compound separated from the water of crystallisation?

Back

Preview of the front of card 4

Card 5

Front

Hydrated copper sulfate has 5 H2O molecules for each unit of CuSO4. What is it's empirical formula?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Atoms and reactions resources »