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Chapter 14.2 Gas Laws. By: Suzanna Hadjinian Quarter 4 Tech Project. Key Points: If the temperature is constant, as the pressure of the gas increases, the volume decreases. As the pressure decreases, the volume increases.
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Chapter 14.2Gas Laws By: Suzanna Hadjinian Quarter 4 Tech Project
Key Points: If the temperature is constant, as the pressure of the gas increases, the volume decreases. As the pressure decreases, the volume increases. Boyles law states that for a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure. Mathematical expression for Boyles law: Boyle’s Law: Pressure and Volume
Key Points As the temperature of an enclosed gas increases, the volume increases, if the pressure is constant. Charles Law states that the volume of a fixed mass of gas is directly proportional to its Kelvin tempurature if the pressure is kept constant. Charles Law: Temperature and Volume
Key Points: As the temperature of an enclosed gas increases, the pressure increases, if the volume is constant. Gay-Lussacs law states that the pressure of a gas is directly proportional to the Kelvin temperature if the volume remains constant. The ratios P1/T1 and P2/T2 are equal at constant volume. Gay-Lussac’s Law: Pressure and Temperature
The combined gas law is a combination of Boyle’s, Charles, and Gay-Lussac’s laws. Key Points: The combined Gas Law describes the relationship among the pressure, temperature and volume of an enclosed gas. The combined gas law allows you to do calculations for situations in which only the amount of gas is constant. The Combined Gas Law
Boyles Law Examples: #1 A sample of carbon dioxide occupies a volume of 3.50L at 125kPa pressure. What pressure would the gas exert if the volume was decreased to 2L ? (3.50L)(125kPa) = (2.00L)P2 P2 = 219kPa #2 . A gas occupies 12.3 liters at a pressure of 40.0 mm Hg. What is the volume when the pressure is increased to 60.0 mm Hg? (40.0 mm Hg) (12.3 liters) = (60.0 mm Hg) (x); x = 8.20 L #3 500.0 mL of a gas is collected at 745.0 mm Hg. What will the volume be at standard pressure? ( 745.0 mm Hg) (500.0 mL) = (760.0 mm Hg) (x)
Charles Law Examples: #1 Calculate the decrease in temperature when 2.00 L at 20.0 °C is compressed to 1.00 L. (2.00 L) / 293.0 K) = (1.00 L) / (x); x = 146.5 K #2 What change in volume results if 60.0 mL of gas is cooled from 33.0 °C to 5.00 °C? (60.0 mL) / (306.0 K) = (x) / (278.00 K) #3 A 600.0 mL sample of nitrogen is warmed from 77.0 °C to 86.0 °C. Find its new volume if the pressure remains constant. (600.0 mL) / (350.0 K) = (x) / (359.0 K)
Gay-Lussac’s Law #1 Determine the pressure change when a constant volume of gas at 1.00 atm is heated from 20.0 °C to 30.0 °C. 1.00 atm / 293 K = x / 303 K; x = 1.03 atm. #2 A gas has a pressure of 0.370 atm at 50.0 °C. What is the pressure at standard temperature? 0.370 atm / 323 K = x / 273 K; x = 0.313 atm #3 A gas has a pressure of 699.0 mm Hg at 40.0 °C. What is the temperature at standard pressure? 699.0 mm Hg / 313 K = 760 mm Hg / x
Combined Gas Law • If I initially have 4.0 L of a gas at a pressure of 1.1 atm, what will the volume be if I increase the pressure to 3.4 atm? (1.1 atm)(4.0 L) = (3.4 atm)(x L) x = 1.29 L