Title: Lesson 9: Relationship between Volume, Temperature and Pressure Learning Objectives: Recall the different gas laws Identify when to use the different gas laws

Look at the diagrams – if the pressure, what happens to the volume? Pressure of a gas in inversely proportional to its volume. The product of pressure and volume is a constant. BOYLE’S LAW

What happens when particles of a gas are heated? There is an increase in the average kinetic energy of the particles. If the pressure is held constant, what happens to volume? There is a proportional increase in the volume How can you describe the relationship between temperature and volume? CHARLES’ LAW

What happens when particles of a gas are heated? There is an increase in the average kinetic energy of the particles. If the volume is held constant, what happens to pressure? There is a proportional increase in the pressure How can you describe the relationship between temperature and pressure? GAY-LUSSAC’S LAW

Q: Why do pressurised cans often carry a warning to be stored in a cool place? Higher temperatures in a fixed volume will mean an increase in pressure. This can cause the can to explode!

These three gas laws can be summarised as follows: BOYLE’S LAW CHARLES’ LAW GAY-LUSSAC’S LAW NOTE: Temperature must be in Kelvin (K)

Ideal gas equation: converting units It is very important when using the ideal gas equation that the values are in the correct units. The units of pressure, volume or temperature often need to be converted before using the formula. Pressure to convert kPa to Pa: × 1000 Volume to convert dm 3 to m 3 : to convert cm 3 to m 3 : ÷ 1000 (10 3 ) ÷ (10 6 ) Temperature to convert °C to Kelvin: + 273

HINT: Look at what information you have… What equation can you use? CHARLES’ LAW

Complete the test yourself questions Page 31 – Questions Check your answers as you go along – page 559