V/T = C

Charles's Law

This law states that volume temperature are directly related. When the number of moles and pressure are held constant, the temperature increases and decreases with the volume

When a syringe is partly filled with air at room temperature and placed in a beaker that contains water that is being heated, the gas will expand as the water is warming. To keep the pressure constant, the plunger will move up and down with the force exerted by the expanding gas.

An experiment was carried out where a new volume is measured every time the temperature within the syringe increases by 10 degrees Kelvin. The number of moles in the syringe, however, does not change. As a result, the force created by the expansion of the gas molecules pushes the plunger upwards causing the volume inside the syringe to increase. Thus, as the temperature increases, so does the volume.

This was the data collected during the experiment:

Analyzing the data shows that V/T is held close to constant despite the varying temperatures (Note: this relationship only holds true if temperature is measured in Kelvin) .

In solving problems involving this relationship where three of four of the variables are known, an equation similar to P₁/T₁=P₂/T₂ can be set up and easily solved by cross-multiplication.

Sample Questions:

 1. In a container that holds 40 Liters, there was 1 mole of oxygen gas at 10'C. If the temperature was raised to 100'C, without changing the pressure, how big does the container have to be to hold that same 1 mole of gas?

2. At 40'C, a 10 liter container held 1.3 moles of chlorine gas. If the container was a 20 liter container, without changing the pressure, to hold 1.3 moles of that gas, how high can the temperature reach?

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PV = C V/n = C P/n = C V/T = C

P/T = C Tn = C

PV=nRT

Answers to Sample Problems

Answers to Sample Test