Solubility of Potassium Chlorate
Length: 686 words (2 double-spaced pages)
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Solubility is the maximum amount of solid that will dissolve in 100g
of solvent. The solubility of a substance depends on the type of ionic
particles in it. So the solubility of each substance is different. The
formula of solubility is:
SOLUBILITY(g/100g)= (SOLUTE / SOLVENT) * 100
I did an experiment to prove this and find the solubility of potassium
chlorate, an ionic solid.
2g potassium chlorates, some distilled water, a stand, a clamp, two
beakers, a thermometer, a test tube, and a measuring cylinder.
1. Put the potassium chlorate into the test tube, and then put 4g
2. Then the solute (which is the salt) dissolves in water (the
solvent) by heating. A solution is made, this is the dissolved solute
in solvent. The solution is left to cool down, and the temperature at
which the solute crystallizes is recorded.
3. Put more 4g water in the test tube. This makes the crystals
4. Do these things more than 6 times.
5. Make a table of the result.
6. Draw a graph, using a line of best fit.
Table of the results:
Total grams of KClO3 g
Total volume of distilled water cm3
Temperature at which solid come out of solution oc
Solubility of H2O g/100g
If there was more time I could have repeated this work to make sure
this information was reliable but I could not.
Look at the table and the graph above. These results were obtained by
the experiment described. You can use the data and the graph to get
some information about the solubility of ionic compounds in water. If
a solid is soluble in a liquid, it usually gets more soluble as the
temperature rises. The solubility that is in a high temperature is
larger than another one, which is in a low temperature. Temperature
will affect solubility. If the solution process absorbs energy then
the solubility will be increased as the temperature is increased. If
the solution process releases energy then the solubility will decrease
with increasing temperature.
The solution may be saturated, but it likely is less than saturated.
Only when some solid remains undissolved are you sure it is saturated.
The presence of undissolved solid suggests that the solution is
saturated. From the graph, 25 g KClO3 dissolve at 70 Â°C, and 50 g KClO3
dissolve at 96 Â°C.
The graph shows me that I can get different kinds of information about
solubility of this solid in water.
1. I can get the solubility of KClO3 at any temperature. For exampleâ€¦..(use
graph) This means I can get the solubility of KClO3 at any
2. The solubility at 20oC is â€¦ if I double this temperature to 40oC
the solubility value is. This has not doubled in value. This shows
that solubility is not proportional to rise in temperature. The
solubility vs. temperature is a curve.
3. to show that solubility is not proportional to temperature I tried
to get a straight line by making temperature = 1/T and use the
equation y = mx + c. Where y = solubility and x = 1/T oC. I still got
a curve. This proved my prediction.
4. The graph also shows me the temperature at which crystals will
first appear if I cool the solution. For example â€¦â€¦â€¦â€¦â€¦â€¦â€¦..
5. I can also get information about the mass of solid I can get when I
cool the solution. If I cool from â€¦â€¦ to ,I can get â€¦â€¦â€¦â€¦..of crystals
will form. (use graph to give this information)
6. From the graph I can show that above the solubility line the
solution is saturated and solid appears. A saturated solution is â€¦.
Below the solubility line the solid is completely soluble and always
exists as a solution.
(you may want to show all this information on your graph)
7. The results are for one set of readings. If time had allowed I
could have repeated the work and obtained at least 3 sets of results
and used the average. The results would have been more reliable.
However, the solubility line I got gave me enough information to
explain the solubility of solid in solvent.
8. If I had obtained the solubility of other salts I could also
compare their saturation temperature and solubility with potassium
Scientific explanation of solubility
Ionic compounds exist as giant ionic structures. There is a strong
force of attraction between the opposite charged ions. A lot of energy
is needed to break up this strong force
â€¦..(explain how water breaks up the crystal structure and surrounds
the ions and how the amount of solid in water affects its solubility.
Use the ionic model from your notes..)
(Anya: you must try to interpret your graph. Explain the line and give
information form the graph. I have tried to show you this by giving
you all the points necessary. Please try to understand these points
and write them in your own style, using your own words. Do not use my
words but only be guided by them.)