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#1. Boyles Law - 1662 Pressure x Volume = a constant Equation: P 1 V 1 = P 2 V 2 (T = constant) Gas pressure is inversely proportional to the volume, when temperature is held constant.

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Graph of Boyles Law page 418 Boyles Law says the pressure is inverse to the volume. Note that when the volume goes up, the pressure goes down

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- Page 419

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Jacques Charles (1746-1823) French Physicist Part of a scientific balloon flight on Dec. 1, 1783 was one of three passengers in the second balloon ascension that carried humans This is how his interest in gases started It was a hydrogen filled balloon good thing they were careful!

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#2. Charless Law - 1787 The volume of a fixed mass of gas is directly proportional to the Kelvin temperature, when pressure is held constant. This extrapolates to zero volume at a temperature of zero Kelvin.

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Converting Celsius to Kelvin Gas law problems involving temperature will always require that the temperature be in Kelvin. (Remember that no degree sign is shown with the kelvin scale.) Reason? There will never be a zero volume, since we have never reached absolute zero. Kelvin = C + 273 C = Kelvin - 273 and

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- Page 421

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Joseph Louis Gay-Lussac (1778 1850) French chemist and physicist Known for his studies on the physical properties of gases. In 1804 he made balloon ascensions to study magnetic forces and to observe the composition and temperature of the air at different altitudes.

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#3. Gay-Lussacs Law - 1802 The pressure and Kelvin temperature of a gas are directly proportional, provided that the volume remains constant. How does a pressure cooker affect the time needed to cook food? (Note page 422) Sample Problem 14.3, page 423

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#4. The Combined Gas Law The combined gas law expresses the relationship between pressure, volume and temperature of a fixed amount of gas. Sample Problem 14.4, page 424

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The combined gas law contains all the other gas laws! If the temperature remains constant... P1P1 V1V1 T1T1 x = P2P2 V2V2 T2T2 x Boyles Law

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The combined gas law contains all the other gas laws! If the pressure remains constant... P1P1 V1V1 T1T1 x = P2P2 V2V2 T26T26 x Charless Law

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u The combined gas law contains all the other gas laws! u If the volume remains constant... P1P1 V1V1 T1T1 x = P2P2 V2V2 T2T2 x Gay-Lussacs Law