The Solubility of Potassium Nitrate
The purpose of this experiment was to observe how temperature affected the solubility of solid potassium nitrate that was put in different solvents. The temperature was not the other thing that was being varied to observe the solubility of potassium nitrate, the amount solute was also varied and the kinds of solvents in this experiment were varied. The nature of each solvent changes due to the common ion effect which is basically means that the concentration of a soluble salt is reduced if there is a common ion with that salt. Also potassium nitrate solubility in basic and acidic places was also determined, to see if it affected the temperature. The moles of KNO3 s/ Kg solvent were needed to calculate the correct molal concentration. Another goal or purpose of this experiment was to calculate the heat of solution of each of the different concentrations. The inverse temperature and a linear plot of the molal concentration were needed to calculate this. The linear equation needed to calculate this was In(s)= -( H/ 2R)(1/T)+(1/2) where R is a constant and T was the temperature. The linear regression model could also be use to approximate the heat of solution. Where finding the heat of solution could be important is when we are trying to figure out the enthalpy change of a solution.
The procedures for this experiment were followed as those printed on pages 221-223 of the manual, experiment number 36 (see references). Deviations in this experiment from the what was printed in the procedure was that Microsoft excel was needed to make the graph instead of using the graph paper provided at the end of the experiment.
Data and Results
The first eight graphs show the relationship between the temperature of the solution and the nature log of each specific molal concentration. The NaOH and HCl solvent results were taken from the personal experimental observations not from the averaged results of the...