 Today we want to talk about one of the many gas laws being Charles' law. What Charles' law tells us, as you can see here, is that the volume of a gas is directly related to the Kelvin temperature when there is no change in the pressure or the amount of gas. So Charles' law looks at the relationship between volume and temperature of a gas. As you can see here, the equation for Charles' law is V1 over T1 is equal to V2 over T2. V1 and T1 is the volume and temperature of a gas under, let's say, condition number one. V2 and T2 is the volume and temperature of the same gas at condition number two. Whenever you're looking at Charles' law graphically, you see if we graph volume versus temperature, since there is a direct relationship, as your temperature in Kelvin increases, your volume will also increase. Next, let's look at an example of using Charles' law in calculations. So we have an example problem here that we have a sample of neon gas that has a volume of 3.1 liters and a temperature of 12 degrees Celsius. Find the new volume of the gas if the temperature rises to 32 degrees Celsius and the pressure and the amount of gas stays constant. So the first thing you need to do is determine what variables the problem gives to you. So it tells us that this neon gas in condition number one has a volume of 3.1 liters. It also tells us that temperature at condition number one is 12 degrees Celsius. However, as we stated over here, the temperature has to be in Kelvin. So in order to convert a Celsius temperature to Kelvin, we add 273. The problem also tells us that we increase the temperature to 32 degrees Celsius. So that is going to be our temperature at condition number two. Once again, it being in Celsius, we have to convert that temperature to Kelvin by adding 273. So our temperature number one will be 285 Kelvin and our temperature number two will be 305 Kelvin. The one variable that was not giving to us and that we are asked to solve for is our volume at condition number two. In order to solve this problem, we must use the formula for Charles' law. We input each variable and then solve for the one variable that we need. In order to solve for V2, we need to move this 305 Kelvin to the left side of the equal sign. In order to do that, we multiply by the inverse so that our 305 Kelvin will cancel out. What we do to one side of the equal sign, we have to do the other side. So our formula to solve for V2 is going to look like this. 305 Kelvin multiplied by 3.1 liter. We are going to divide those by 285 Kelvin. The way that you can check your work and make sure that you are correct is by looking at the units in which units cancel out. You see here that we have Kelvin on top and on the denominator which would mean that they would cancel out. The only unit we are left with is liters and volume is measured in liters. Whenever you calculate this value out, you see that V2 is going to be equal to 3.3 liters. And this corresponds with Charles' law because if we increase the temperature of our gas keeping pressure and the amount of gas constant, we would expect our volume to increase from 3.1 to 3.3. That shows the direct relationship between the volume and temperature of a gas.