Effect of Temperature on Solubility of Potassium Chloride in Water

890 Words Jun 29th, 2013 4 Pages
IB Chemistry Lab Report Design Example—

Effect of Temperature on Solubility of Potassium Chloride in Water

Research question

How does temperature affect the solubility of potassium chloride in water?

Hypothesis

As the temperature of water increases, the particles of solid Potassium chloride, KCl, which are absorbing energy from its surrounding, start moving more easily between the solution and its solid state because. According to the second law of thermodynamics, the particles will shift to the more disordered, more highly dispersed solution state. I predict that as the temperature of a KCl and water mixture increases, then the solubility of the KCl will also increase.

Variables

Dependant variable

The dependant
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The use of different syringes for the extraction of the Potassium chloride and distilled water solution from each beaker avoids the possibility of contamination in the case where the same syringe was used in all 6 beakers.

The needle of the syringe should be placed at the midpoint between the surface of the solution and the bottom of the beaker upon extraction. This is because of it were placed at the surface of the solution some air particles might enter the syringe, and if it were placed at the bottom of the beaker some undissolved particles might be extracted, thereby leading to an increase in the actual concentration of the dissolved salt.

The weight of each 50ml beaker (used for weighing the mass of dissolved Potassium chloride after the evaporation of water) should be recorded. If the experimenter were to weigh the mass of one beaker and take it as a default mass, the latter may be a source of error.

In order to minimize errors and to "place" the solutions in the same environment, the same volume should be extracted from each solution using the syringes.

After heating the extracted solution in the 50ml beaker for weighing purposes, some of the water might condense back into the liquid state (in the form droplets), thereby leading to an increase in the calculated weight of Potassium chloride. Therefore
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