Investigation to Identify the Formula of Hydrated Copper Sulphate

Investigation to Identify the Formula of Hydrated Copper Sulphate

Aim: I plan to investigate the formula of Hydrated Copper Sulphate

and, more importantly, what x stands for in the formula (CuSO4.xH2O).

This will tell me how many molecules of water surround each molecule

of Copper Sulphate. To do this I plan to work out the amount of water

a set mass of Hydrated Copper Sulphate loses when it becomes

anhydrous. I will work this out by measuring the difference in mass

between the two states. And thus ascertain the degree of hydration.

I predict that because it is hydrated copper sulphate and it is blue

that it will contain water of crystallization surrounding the copper

sulphate. The number of water molecules per copper sulphate molecule

should fall somewhere between 1 and 5 as 1:5 is the largest ratio of

copper sulphate to water this molecule can contain.

Apparatus:

MATERIALS: Hydrated copper (II) sulphate

GENERAL:

§ Heatproof mat,

§ Tripod,

§ Bunsen burner,

§ Pipe clay triangle,

§ Crucible,

§ Metal tongs,

§ Glass mixing rod,

§ Spatula,

§ Electronic-Balance

SAFETY: Lab coat and safety glasses to be worn at all times

and care to be taken when handling hot objects.

Method:

1. Set up apparatus as shown in the diagram.

2. Find the mass of crucible by itself.

3. Place 2-3 spatulas of Copper sulphate into the crucible.

4. Find the mass of the crucible and copper sulphate.

5. Work out the difference in mass to find the mass of the copper

sulphate.

6. Heat until powder has gone white but do not...

... middle of paper ...

...h development of the sample, and

more frequent processing on the scales. Another main improvement that

could be implemented had the equipment been available would be to

completely automate the experiment to remove the degree of human

error. This would involve using very accurate robotic machines to

precisely measure the amount of copper sulphate used and the mass of

everything. It would also heat it for the exact amount of time to

prevent burning (oxidization) or to not be fully dehydrated.

In addition to this, either repetition of the experiment to obtain a

broader spread of results or a collation of class results may have

yielded more accurate results, as the mean of the results would

probably have given a ratio for hydrated copper (II) sulfate much

closer the accepted literature value of 1 : 5, or CuSO4 · 5H2O.