Day 3: Volume and Temperature Relationships

Charles Law I: Ideal Gas Law

Volume vs. Temperature

We used the above set-up to test the relationship between volume and temperature. The glass syringe was set to 4cc at room temperature. We then proceeded to placing the flask in cooler and warmer environments in order to observe what happened to the volume as the temperature increased and decreased.

We first however needed to calculate the true volume of the flask. We did this by weighing the flask when it was empty. Then we filled the flask full of water making sure to account for small tubes in the rubber stopper. Once filled with water we reweighed the flask and recorded its final mass.  We then subtracted the two masses and found the volume of the flask occupied by the water (139.2 cc).

The flask was then placed inside of large beaker with warm (33.9°C) water, picture on the right. As the flask was submerged we saw the the the volume in the syringe increase to 8.2cc. This is what we expected to happen, because when temperature is increased the gas molecules begin to move faster and collide more often with the walls of the container. In order to keep pressure constant, the volume must be increased to accommodate the faster moving gas molecules. 

The picture on the left shows the flask being placed in a cup of cooler (23.5°C) water. Decreasing the temperature made the volume in the syringe decrease below 4cc to about 1.6cc. This also makes sense because a decrease in temperature would result in a decrease of pressure. In order to make sure that pressure was constant the volume needed to decrease. 

After all our data was recorded we plotted the volumes and temperatures into graph in excel. 

After plotting the data points we discovered that the relationship between volume and temperature was in fact linear. If temperature increases then volume must also increase because they are directly proportional. The slope for this linear graph was 0.6259, this number represents the constant C in the below image.

The above two pictures show that the relationships between Volume and Temperature. One photo proves mathematically that they are in fact proportional (right). The other photo shows what the units for the slope of the Volume vs Temperature graph should be (left).