lab on solutions

I Introduction

A. Purpose: The purpose of this experiment was to determine if the temperature of water effects the rate at which salt dissolves.

B. Hypothesis: If the temperature of the water increases then the rate at which the salt dissolves will increase.

C. Science Concepts: Solution- one substance dissolved in another

Solute- the substance that gets dissolved

Solvent- the substance that the solute gets dissolved in

Characteristic property- a property that is unique to a substance, does not change depending on the amount of a substance, and can identify the substance

Physical change- when a substance changes physically but is not chemically effected

Solubility- the amount of a substance that can be dissolved in a given amount solvent at a given temperature

In the experiment the solubility of salt was tested in different temperatures of water. The solute was the salt and the solvent was the water. The salt dissolved in the water to form a solution. When the salt dissolved a physical change took place. Solubility along with melting point, freezing point, and density is a characteristic property.

II Procedure

1. massing cups and a triple beam balance were used to measure 0.5 grams of salt

2. 100 ml of cold water was measured and poured into a beaker using a graduated cylinder

3. the temperature of the water was measured and recorded on a data table

4. the salt was poured into the water and the stop watch was started

5. the water was stirred as the salt crystals dissolved

6. the number of seconds it took for the salt to dissolve was measured and recorded on a data table

7. the experiment was repeated using room temperature and warm water

8. each group did one trial

III Results/Conclusions

A. Experimental Data: The results of the experiment indicate that the warmer the solvent was the faster the solute dissolved. When the water was 9°C it took 51.66 seconds to dissolve. When the water was 57°C it took only 13.15 seconds to dissolve.

B. Graphs and Tables: see attached

C. Evaluate Prediction/Hypothesis: The results of the experiment support the hypothesis. The hypothesis stated that the slat would dissolve faster if the water was heated. The salt in the warmer water dissolved about four times faster than the salt in the cold water.

IV Extension and Summery

A. Extension: Some causes of experimental error may have been how fast the stirrer was stirring. This could have been fixed by having the same person stirring each time.