A gas occupies a volume of 502 cm3 at 20.0 C. What will be its volume at 106 C?

I understand that it follows Charles' Law where the correct equation is V1/T1=V2/T2. My teacher expects all units of volume to be converted to Liters and all temperature to Kelvins. Using Celsius provides the answer of 2.22 L while Kelvins provides 0.649 l. Using Celsius gives a much more reasonable answer since volume increases proportionately to temperature. Are her instructions using Kelvins justified? I have converted pressure to atmospheres and volume to Liters and receive reasonable answers or answeres identical when not converting.

You logic is good but logic based on false assumptions is useless and leads down the wrong path. It is true that volume is proportional to temperature BUT IT IS TEMPERATURE IN KELVIN and not temperature in celsius. That's why you convert C to kelvin. As for the conversion to L, that is a personal preference of your teacher. Using cc for V1 will give units of cc for V2. Using L for V1 will give units of L for V2. For this problem 0.649 L is the correct answer.

Your teacher's instructions to use Kelvin for temperature in the equation V1/T1 = V2/T2 are justified. Allow me to explain why:

When it comes to gas laws like Charles' Law, it is essential to use the Kelvin scale for temperature calculations rather than Celsius. This is because the Kelvin scale is an absolute temperature scale that starts from absolute zero, which is the point at which all molecular motion ceases.

The relationship between temperature and volume in Charles' Law is a direct proportionality - as the temperature increases, the volume of a gas also increases proportionally, assuming other conditions remain constant. Therefore, when looking at changes in temperature, it is crucial to use an absolute temperature scale like Kelvin.

The Kelvin scale doesn't have negative values, making it ideal for these types of calculations since negative temperatures would result in undefined or unrealistic values.

Converting the temperature from Celsius to Kelvin is simple – you just need to add 273.15 to the Celsius temperature. For example, 20.0 degrees Celsius would be converted to 293.15 Kelvin.

Now, let's see how this conversion affects the given problem:
1. Convert the initial temperature of 20.0 °C to Kelvin: 20.0 + 273.15 = 293.15 K
2. Convert the initial volume of 502 cm³ to liters: 502 cm³ ÷ 1000 = 0.502 L
3. Convert the final temperature of 106 °C to Kelvin: 106 + 273.15 = 379.15 K
4. Use the Charles' Law equation: V1/T1 = V2/T2
Substitute the given values: 0.502 L / 293.15 K = V2 / 379.15 K
5. Solve for V2: V2 = (0.502 L / 293.15 K) * 379.15 K = 0.648 L (rounded to three decimal places)

As you can see, by converting the temperature to Kelvin, the answer becomes 0.648 L, which is indeed consistent with Charles' Law. Converting all units to appropriate forms ensures accurate and consistent results.