Charles’ Law

Let’s first Recall Boyle’s Law P1V1 = P2V2

STP vs SATP STP SATP temperature pressure volume Fill in the table using yesterday’s notes

Changing Celsius to Kelvin To change from celsius to Kelvin we add 273. Example: 34oC = K 548K = oC 0oC = K -14oC = K

Invent and Discuss an Experiment Design an experiment (like yesterday) to test the effect of increasing or decreasing the temperature on the volume of a gas (think about Arielle’s example yesterday) What would you do? How would you measure the volume change? What are your variables and constants? 10 minutes

My experiment

Recall the Kinetic Molecular Theory 1. 2. 3.

What happens to molecules as the temperature increases?

Charles’ Law V1 = V2 T1 = T2

Charles’ Law As the temperature of a gas increases, the volume increases proportionally, provided that the temperature, pressure and the chemical amount of gas remain the same

In other words As the temperature increases the volume increases by the same rate (for a gas at constant temperature and pressure)

Example In a test of Charles’ law, a gas inside a cylinder with a movable piston is heated to 315 Celsius. The initial volume of gas in the cylinder is 0.30L at 25 Celsius. What will be the final volume when the temperature is 315 Celsius?

List the givens What are we looking for? Rearrange the equation

Sub in the numbers to get the final answer:

ABSOLUTE ZERO If a gas did not liquefy its volume would become zero at -273oC (= 0 Kelvin) or ABSOLUTE ZERO. Absolute zero is the lowest possible temperature Scientists have gotten to 100picoKelvin above absolute zero (100 trillionths of a Kelvin)

Wha?? Before you go answer this How does a thermometer work (according to KMT and Charles’ Law)? And where else can you see Charles’ Law in action?