Chapter 14 Gas Laws

Gas Law Activities Working at your table. Need: Plunger Whiteboard Marker Eraser Plunger 5 physics books 2-Liter w/water-do not open!!!!

Book Activity On your whiteboard graph your results Pressure(number of books) vs. Volume in mL. Cartesian Diver Answer the following questions on your whiteboard also. What happens when you squeeze the bottle? Are you increasing or decreasing the pressure in the bottle? Look closely at the dropper in the bottle, what (other than water) is in the dropper? When you squeeze the bottle what happens to the volume of the (non-water) contents of the dropper? Is it increasing or decreasing?

Boyle’s Law Volume and pressure are inversely related. Pressure increased with the number of books and the volume of air in the syringe decreased. Squeezed the bottle increased pressure in the bottle which caused the volume of air in the dropper to decrease. Causing the dropper to sink in the bottle.

ChemThink Gas Tutorial

Behavior of Gases WS Answer questions 1-5.

Boyle’s Law P1V1 = P2V2 1 = original 2 = new Robert Boyle Relationship between pressure and volume when temperature is held constant. P1V1 = P2V2 1 = original 2 = new Units need to be the same on both sides of the equal sign. Hyperbola *Volume drops by half *Pressure Doubles *Inverse relationship There is 2.50 L of a gas @ 100 kPa, when the pressure decreases to 40 kPa what would the new volume be? Pressure and Volume are Inversely related Pressure  by 2.5 Volume  by 2.5

Charles’ Law V1 = V2 T1 T2 Jacques Charles Relationship between volume and temperature when the pressure is held constant. V1 = V2 T1 T2 Temperature = Must be in Kelvin Volume units need to be the same. Kelvin = °C + 273 Linear Volume and Temperature are directly related. A sample of gas has an initial volume of 150 mL @ a temperature of 13°C if the volume of gas increased to 233 mL what is the new temperature of the gas? Volume  by 1.55 Temperature by 1.55

Gay-Lussac’s Law P1 = P2 T1 T2 Relationship between pressure and temperature when the volume is held constant. P1 = P2 T1 T2 Temperature = Must be in Kelvin Pressure units need to be the same. Linear Pressure and Temperature are directly related. A gas has a pressure of 6.85 kPa at a temperature of 540 K if the temperature is decreased to 210 K, what would the new pressure of the gas be? Temperature  Pressure 

Combined Gas Law P1V1 = P2V2 T1 T2 All previous laws combined. Temperature must be in Kelvin. Other variables P & V units need to match. A gas at 1.o atm and 25 °C has a volume of 1.0 L. What volume would this gas occupy if the pressure and temperature were both increased to 6.0 atm and 100 °C ?

Assignment Determine the equation to use for problems 6, 7, 8, 10, and 12. For Monday solve problems 6, 7, 8, 10, and 12 on Behavior of Gases WS. You will need your books on Monday!!!!

The gas in a closed container has a pressure of 315 kPa at 30°C The gas in a closed container has a pressure of 315 kPa at 30°C. What will the pressure be if the temperature is lowered to -172°C? A gas with a volume of 4.0 L at 90.0 kPa expands until the pressure drops to 20.0 kPa. What is the new volume ? A gas with a volume of 300. mL at 150.0°C is heated until the volume expands to 600. mL. What is the new temperature of the gas? A 3.50 L gas sample at 20.o°C and a pressure of 86.7 kPa expands to a volume of 8.00 L. The final pressure of the gas is 56.7 kPa. What is the final temperature in degrees Celsius?

A 3. 50 L gas sample at 20. o°C and a pressure of 86 A 3.50 L gas sample at 20.o°C and a pressure of 86.7 kPa expands to a volume of 8.00 L. The final pressure of the gas is 56.7 kPa. What is the final temperature in degrees Celsius?

Note Cards Boyle’s Law Relationship and Equation Charles Law Relationship and Equation Gay-Lussac’s Relationship and Equation Combined Gas Law Equation Kelvin = °C + 273 *Convert to Kelvin BEFORE you solve* STP= 0 °C and 1 atm/101.3 kPa/760 mmHg 1-8 on Gas Laws Practice Due tomorrow, will be collected!

Ideal Gas Law Need to recognize the volume occupied by a gas @ a specific temperature and pressure depends on the # of gas particles. The # moles of a gas is directly proportional to the # of gas particles. Ideal gas law relates volume of a gas and the moles of gas particles. PV=nRT

PV=nRT When pressure is in kPa R=8.31 When pressure is in mmHg R= 62.4 P=Pressure V=Volume –Must be in Liters n= # of moles T=Temperature-Must be in Kelvin R=Ideal Gas Constant Pressure and R value need to have the same unit 3 R values When pressure is in kPa R=8.31 When pressure is in mmHg R= 62.4 When pressure is in atm R=0.0821

What volume will 12.o g of oxygen gas occupy at 25°C and a pressure of 52.7 kPa? If 4.50 g of methane gas is in a 2.00 L container at 35°C, what is the pressure in the container? A helium filled weather balloon has a volume of 240. 0 L at 99 kPa pressure and a temperature of 0°C. What is the mass of helium in the balloon?

Assignments Do 9, 11, and 13 from Behavior of Gases WS-Due tomorrow. Reminder 1-8 on Gas Law Practice WS due tomorrow also.

Turn in Gas Law Practice WS (1-8) should be done. Go over 9, 11, and 13 from Behavior of Gases WS Dalton’s Law Book Assignment due Friday end of the hour: pg 468 32-33, pg 471 37-38, pg 480 55,58,60,61

Dalton’s Law of Partial Pressure In a mixture of gases the total pressure is the sum of the partial pressures. PTotal = P1 + P2 + P3 …… Determine the total pressure of a gas mixture that contains oxygen, nitrogen, and helium if the partial pressures of the gases are PO2=20.0 kPa, PN2 = 46.7 kPa, PHe = 26.7 kPa 20.0 + 46.7 + 26.7 = 93.4 kPa

A balloon contains mostly helium and a little methane A balloon contains mostly helium and a little methane. The partial pressure of helium is 100.2 kPa. If the pressure inside the balloon is 101.30 kPa, what is the partial pressure of methane? 101.30 kPa = 100.2 kPa + Pmethane Pmethane = 1.10 kPa