Volume & Temperature Relationship Charles’s Law Volume & Temperature Relationship

In 1787, Jacques Charles discovered that volume and temperature of a gas are related in mathematical terms. Increasing the temperature of a gas by 273OC , at a constant pressure, increases the volume by 2.

Here's what Charles did:   He put a gas into a container in which he could change the temperature and measure the volume.  Here's what Charles did: 350 300 250 200 150 100 50 NASA LINK

100mL / 10K = k Temperature (K) 350 300 250 200 150 100 50 10 K When he divided the volume of the gas times it's temperature, he found it was equal to some arbitrary number (let's call it k, because he did). 100mL / 10K = k Temperature (K) 350 300 250 200 150 100 50 10 K Volume (mL)

Temperature (K) 350 300 250 20 K 200 150 100 50 10 K Volume (mL) If he changed the temperature of the gas, he found that the volume also changed. Temperature (K) 350 300 250 20 K 200 150 100 50 10 K Volume (mL)

100mL / 10K = k 200mL / 20K = k Temperature (K) 350 300 250 20 K 200 What is surprising is that if you divide the new volume by the new temperature, the answer is the same arbitrary number that you had in the first place (k!).  100mL / 10K = k 200mL / 20K = k Temperature (K) 350 300 250 20 K 200 150 100 50 10 K Volume (mL)

Here’s what You’ll do: -15oc 5oc 65oc

Data Table Water Bath Temp oC Average Volume V T oC Absolute Temp K V T K Saltwater- Ice Ice water Room Temp. Hot Water

Lab Procedure 1. Read Lab Instructions 2. Set Syringe at specified volume 3. Test & Record & Calculate Data 4.Return to seat to answer discussion questions

TEMPERATURE MUST BE IN KELVINS Charles’s Law Charles's Law states that as Temperature increases in a gas, Volume increases! T↑ V↑ This is the basis for his law. V1 = V2 T1 T2 TEMPERATURE MUST BE IN KELVINS

V1 = V2 T1 T2 In this equation: T1 is the initial temperature of the gas V1 is the initial volume of the gas T2 is the final temperature of the gas V2 is the final volume of the gas.  This way, if you know the initial temperature and volume of a gas and know what the final temperature will be, you can predict what the volume will be after you change the temp.  Let's see an example.

Example Problem Q: Find the final volume, in Liters, using Charles's Law and the following info: T1= 273 K V1= 2.0L T2= 300 K V2=? 1) Write down formula: V1 = V2 T1 T2 2) Plug in numbers: (2.0) = (V2) (273) (300) 3) Solve for V2 using Algebra (multiply by 300 on both sides): (300)(2.0) = (300)(V2) (273) (300) 4) Multiply and divide (the Kelvins cancel, so you're left with L): (300)(2.0)/(273)= 2.2L 5) You're done! V2=1L