Experiment to develop the relationship between the pressure and volume of a gas.

2. Experimentto develop the relationship between the pressure and volume of a gas. • Include: Boyle’s Law • Experiment to develop the relationship between the volume and temperature of a gas. • Include: Charles’ Law, Absolute zero, Kelvin scale, ideal gas • Additional KEY Terms • Inverse relationship • Direct relationship

3. BOYLE’S LAW: The volume of a given amount of gas (held at a constant temperature) varies inversely with the pressure. P α1 V

4. BOYLE’S LAW – Pressure vs. Volume Pressure (kPa) Volume (mL)

5. What will be the volume of 40 L of gas (held at a constant temperature) if the pressure is doubled? Reduced to 1/3rd ? P α1 V 2α1 2 20 L 1 = 3 1/3 1/3α1 1/3 120 L

6. P α1 V • PV = k = • P2V2 P1V1

7. If 3 L of gas is initially at a pressure of 1 atm, what would be the new pressure required for a volume of 0.5 L? P1V1 • P2V2 = (0.5) (1)(3) • P2 = 6 atmof pressure will change 3 L of a gas at 1 atm to 0.5 L.

8. A syringe contains 20 mL of a gas at 100 kPa. The pressure in the syringe is changed to 25 kPa. What is the new volume of the gas? P1V1 • P2V2 = (25) (100)(20) • V2 = The gas will expand to 80 mL.

9. Absolute Zero

10. Jacques Charles(1746-1823) • Volume of gas changed with only1oC change in temperature. An increase of 273°C, doubled the volume. CHARLES’S LAW: Volume of a given gas (held at a constant pressure) varies directly with the temperature V α T

11. CHARLES’S LAW – Temp vs. Volume Volume (mL) ? Temperature (oC)

12. William Thomson(1824-1907) • Created Kelvin Scale where –273°C is the lowest temperature possible or Absolute Zero • TK = TC + 273 TC = TK - 273 • Stated as “315 Kelvin”- no degrees. • predicts that with zero kinetic energycomes • zero volume • called an ideal gasmodel

14. V α T • V = k • T • T1 • T2 V1 • V2 = • **All temperatures must be in Kelvin.

15. What is the new volume of a gas if 100 mL of the gas at 25°C is cooled to –25°C? V1 • V2 = 100 • -25 • V2 = • T1 • T2 • 25 25°C + 273 = 298 K–25°C + 273 = 248 K • (248) 100 • 83.2 mL = • 298 The new volume is 83.2 mL.

16. If the volume of a gas at –73°C is doubled to 48.0 L, calculate the final temperature in degrees Celsius. –73°C + 273 = 200 K V1 • V2 = • T1 • T2 • 48.0 • (200) = • 400 K 24.0 400 K – 273 = 127°C

17. Boyle described the inverse relationship between the pressure and volume of a gas at a constant temperature. • Charles described the direct relationship between the temperature and volume of a gas at a constant pressure. • William Thomson (Lord Kelvin) developed the Kelvin temperature scale. • At zero Kelvin (absolute zero) , the volume of a gas will theoretically be zero. • When solving gas problems the temperature must always be converted to Kelvin.

18. CAN YOU / HAVE YOU? • Experimentto develop the relationship between the pressure and volume of a gas. • Include: Boyle’s Law • Experiment to develop the relationship between the volume and temperature of a gas. • Include: Charles’ Law, Absolute zero, Kelvin scale, ideal gas • Additional KEY Terms • Inverse relationship • Direct relationship