Solubility Curve of Potasium Nitrate

Published by swinoff
September 1, 2010, Category: Chemistry

Determining the solubility of potassium nitrate at different temperatures.

The temperature at which Potassium Nitrate begins to precipitate out of a solution was measured to find the solutions maximum concentration. Each time one more millilitre of water was added the solution was re-heated. The more water that was present the lower the temperature was that the Potassium Nitrate began to precipitate.

Observations:

Table 1

Solubility in g/100ml	ml of distilled water	Temp in °C Precipitate formed
150 g/100ml	2.0 ml	75 °C
100 g/100ml	3.0 ml	62 °C
75 g/100ml	4.0 ml	59 °C
60 g/100ml	5.0 ml	49 °C
50 g/100ml	6.0 ml	42 °C

The solubility of Potassium Nitrate is directly effected by the temperature of the solution. As the temperature of the solution rises the solubility of Potassium Nitrate increases

Evaluation:

Sources of error in the experiment include; possible inaccuracy of equipment, miss measurement of materials, the difference between what one person would determine as a crystal compared to another, the time between when the temperature was recorded and when the first crystal was spotted. Ways to improve and/or eliminate these flaws would be to have the same person each time watch for crystals to form and to have the thermometer always in the test tube.