A relationship between pressure and temperature

1. Equation Piston example Background Example problems quiz Gay-Lussac’s Law Go to: Gas Introduction A relationship between pressure and temperature Charles’ Law Boyle’s Law Combined Gas Law Teacher Page

2. The Equation • Volume and mass of gas are both held constant for this equation • This is a direct relationship, so, when one pressure goes up so does temperature and vice versa.

3. Why is this law true? • As the temperature increases, more kinetic energy is present. The gas molecules are moving at a faster speed. • This in turn leads to the molecules colliding with the edges of the container they are in with greater speed and frequency, which pushes the container and increases the volume. Return to Gay-Lussac’s main menu

4. The Piston example • An automobile uses pistons to generate its power. As the temperature from the combustion of the octane occurs, note what happens to the volume inside the piston. • Gas expansion in a firing piston Return to Gay-Lussac’s main menu

5. Who was Gay-Lussac? • He was the French scientist who first confirmed the relationship between pressure and temperature in gases.

6. Why is it called Gay-Lussac’s Law? • Charles was actually the first to study this relationship and so it is sometimes called the Charles and Gay-Lussac Law • As with the other gas laws involving temperature, the units must be Kelvins and not Celsius. Return to Gay-Lussac’s main menu

7. Example #1 • 20.0 L of a gas is found to exert 67.0 kPa at 35.0°C. What would be the required temperature to change the pressure to standard pressure (101.325 kPa)? • First, convert the temperature to Kelvin

8. Next, we must inventory what we know, need to know, and our equation.

10. Example #2 • 35.0 L of a gas is found to exert 2.5 atm of pressure at 45.2°C. What would be the required pressure to change the temperature to 100.00C? • First, convert the temperatures to Kelvin

11. Next, inventory the problem

12. Return to Gay-Lussac’s main menu

13. Now, its your turn! • See you well you can answer some questions about Gay-Lussac’s Law using this online quiz. • Write your work and final answer to each question on a separte sheet of paper. • We’ll go over each one together to make sure you’re getting • Good luck! Return to Gay-Lussac’s main menu

14. Student Objectives and QCC Standards • This module addresses elements 15.3 and 15.6 in Standard 15 for Secondary Chemistry, Georgia QCC Topic 15. Topic: Solids, Liquids, Gases Standard: Compares solids, liquids, and gases in terms of collision theory and physical properties • 15.3 Uses Boyle’s, Charles’, and ideal Gas Laws to calculate and explain the relationship of temperature and pressure on the volume of a gas. • 15.6 Applies concepts related to the behavior of gases to everyday life (e.g., seasonal tire pressure variation). • Student Objectives: • Students will describe a qualitative and quantitative relationship between the pressure and temperature of a gas at constant mass and volume. • When presented with specific data, students will solve for the missing term in the Gay-Lussac law equation. Gay-Lussac’s Law Module designed by Joe Cozart jcozart@walton.k12.ga.us