3.the presence of other ions.
Apparatus-1.3 beakers
2.a stirring rod
3.filter papers
4.funnel
5.Bunsen burner
6.tripod stand
7.sodium chloride
8.potassium nitrate
9.zinc sulphate
10.spatula
11.flasks
12.distilled water
13.digital balance
Method-
1.take 40 ml of distilled water in the beaker at room temperature and weigh it. Add the given to it and stir with the rod until no more dissolves in it.
2.filter the solution and weigh it
3.heat the solution on the Bunsen burner until the temperature reaches 50-degree Celsius.
4.add the same salt until no more dissolves in it and filter it out.
5.weigh the solution
6.heat the solution further till 80-degree and add salt till no more dissolves in it. Filter it out and weigh it.
7.repeat the procedure with the other two salts.
Mass of the beaker+water (+/-0.01gm)-
Mass of salt dissolved=mass of beaker+salt solution-mass of beaker+water
Conclusion and evaluation-while conducting the experiment it was realized that the following problems were faced-1.the main problem that faced was to keep the temperature constant at 50 and 80 degree Celsius. Also this would cause a problem while the solutions are filtered because as the solution would filter the temperature of the solution would decrease and the dissolved salt would crystallize out and the result would not be obtained. Also due to in convenience, the filtered paper was emptied into the flask as the beaker was too small. Thus some solution would be stuck to the apparatus while making transfers. This can be avoided in the following ways-the solution can be allowed to heat more the 50 or 80 degrees Celsius. Thus the temperature will reach about 50 or 80 degree Celsius when the solution is saturated. Also the Bunsen burner can be left switched on and the temperature reading taken regularly. If the temperature has fallen then the solution can be re heated without much hassle. Also, since it is not sensible to filter the solutions not at room temperature, excess of salt should be added so that the undissolved salt remains at the bottom and solution can just be transferred to another beaker. A problem encountered with this method is that some solution may remain behind and also that some undissolved salt may be accidentally transferred. But anyhow the variations are lesser than when the solution is filtered.
As is seen in the observation table the solubility of a salt increases with increase in temperature. This is because as the kinetic energy of the solute as solvent molecules increase the bonds between ions of the salt and the forces between solute molecules weakens the solute ions easily fit in between molecules thus the solubility increases.
