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Today: Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter Apply Boyle’s Law to problems

Boyle 1627-1691 A founder of modern chemistry Pioneer of the modern scientific method Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

Gas has three properties… Volume Temperature Pressure Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

Determining Boyle’s Law Experimentally. Boyle was a great experimentalist. He often avoided making hypothesis and relied solely on experimental results. Start with a question. How are the pressure and volume of a gas related? Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

Tall wide, glass tube Bourdon Gauge Oil Reservoir Foot Pump

[Pa] [cm3] Pressure Volume Determine and use Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

P∝ Boyle’s Law 1 V PV = constant The pressure of a gas is inversely proportional to its volume. The pressure of a gas is directly proportional to 1/volume. 1 P∝ V PV = constant Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

Assumptions Temperature remains constant Determine and use Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

The volume of a fixed mass of gas at constant temperature is inversely proportional to the pressure. Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

What is happening? Boyle's law simulation Determine and use Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

What is happening? Consider a small box of volume V1 with a gas inside at pressure P1 The gas particles are exerting a force when they bounce off the walls of the box. Pressure is measured in N/m2 (also known as Pascals Pa) Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

If the box shrinks? And all other variables remain constant? There is a smaller surface area so the number of collisions per unit area increases. (P2 is greater than P1) But V2 is smaller than V1 Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

P1V1 = P2V2 https://phet.colorado.edu/en/simulation/legacy/gas-properties Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

Pick the correct equation and rearrange if necessary Write out what you know Pick the correct equation and rearrange if necessary Put the numbers in Don't forget the units

Example Question P1V1 = P2 P1V1 = P2V2 V2 (1 x 105) x (10 x10-6) = P2 A sealed syringe contains 10 x10-6 m3 of air at 1 × 105 Pa. The plunger is pushed until the volume of trapped air is 4 x 10-6 m3. If there is no change in temperature what is the new pressure of the gas? P1V1 = P2 V2 P1 = 1 x 105 Pa V1 = 10 x10-6 m3 V2 = 4 x 10-6 m3 P2 = ? P1V1 = P2V2 (1 x 105) x (10 x10-6) = P2 (4 x 10-6) 2.5 x 105 Pa= P2 Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

2. A syringe with a radius of 4cm and 10cm long is filled with a gas at a pressure of 1.2 x 105 Pascals. The piston is pushed slowly into the syringe until the pressure on the gauge reads 1.8 x 105 Pascals. What is the new volume of gas? [5] Apply Boyle’s Law to problems Determine and use Boyle’s Law Explain Boyle’s Law in terms of the Kinetic Theory of Matter

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