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 Phet

Get out your packet from yesterday.

Behavior of Gases WS Answer questions 1-5. Due Monday

Boyle’s Law P1V1 = P2V2 Robert Boyle Relationship between pressure and volume when temperature is held constant. P1V1 = P2V2 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 

Cole’s Law 6 cups shredded cabbage 1 cup shredded carrot 1 cup mayonnaise ¼ cup white wine vinegar 1 teaspoon celery seed ¼ cup sugar Salt and pepper

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 ?

Determine the equation to use for problems 6, 7, 8, 10, and 12. Assignment Determine the equation to use for problems 6, 7, 8, 10, and 12. For Tuesday solve problems 6, 7, 8, 10, and 12 on Behavior of Gases WS.

Today’s Agenda You will need a whiteboard, marker, and an eraser to share. Chapter 13 Test-If you haven’t taken- you need to by the end of the day or it will be a ZERO! Practice Problems Check Problems 6, 7, 8, 10, and 12. Group Problems

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 ?

You will be earning participation points. Group Problems Working with the person next to you solve as many of these problems as possible on your white board. You will be earning participation points. Group Problems Pages R62-R63 148, 149, 150, 151, 152, 153, 154, 155, 162, 164, 165, 170 When you have one/two done raise your hand and we will check your answer.

A gas with a volume of 300. mL at 150 A gas with a volume of 300. mL at 150.0°C is heated to 575 °C, which causes the gas to expand. What is the new volume of the gas? A 3.50 L gas sample at STP expands to a volume of 8.00 L. The final pressure of the gas is 156.7 kPa. What is the final temperature of the gas?

Note Cards Equations Conversion for Kelvin STP Boyle’s Charles’ Gay-Lussac’s Combined Conversion for Kelvin STP

Gas Law Practice WS 1-8 Due tomorrow Make sure to show all your work and your answer has units.

Turn in your gas law practice WS into the basket Go through Chapter 13 Test Get out your notebooks and notecards

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 R= 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 R=

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 If 4.50 g of methane gas is in a 2.00 L container at 35°C, what is the pressure in the container?

Assignment Do 9, 11, and 13 from Behavior of Gases WS-Due tomorrow.

Practice Problems Return Gas Law Practice WS Check 9, 11, and 13 from Behavior of Gases WS Dalton’s law of partial pressures Assignments-due by end of class tomorrow.

A helium filled weather balloon has a volume of 2 A helium filled weather balloon has a volume of 2.4 L at 99 kPa pressure and a temperature of 0°C. What is the mass of helium in the balloon?

What pressure is exerted by 0. 450 mol of a gas at 25 What pressure is exerted by 0.450 mol of a gas at 25.0°C if the gas is in a 650 mL container?

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 chlorine, nitrogen, and oxygen if the partial pressures of the gases are PCl2=30.0 kPa, PN2 = 16.7 kPa, PO2 = 21.3 kPa 30.0 + 16.7 + 21.3 = 68.0 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

Assignments-Due by end of class time Friday(Will be turned in) Need to show all your work make sure your answer has the correct units. Page 468 32 and 33 Page 471 37 and 38 Page 480 55, 58, 60, 61 Do problems 9, 12-14 on gas law practice WS (10 and 11 do for extra credit)