A: 7 March 2012

Take Out Homework: Week 24 p. 3-4

Objective: You will be able to: describe gas behavior, five

assumptions we make about gases and how they relate to pressure exerted by a gas on their container.

Do now: Brainstorm: Write down everything you know about gases!

Agenda

I. Do nowII. Go over homework answersIII. Percent yield exit ticketIV. Properties of a gas notesV. Be a gas!! Collect and analyze dataHomework: Unit 6 packet page 2:

Thurs.Metacog. worksheet part 2: Thurs.

When you finish the exit ticket

Flip it over Work silently on Week 24 p. 4: due

Weds. if you haven’t already finished it.

A: 8 March 2012

Take Out Homework: Packet p. 2 and Metacog. worksheet

Objective: You will be able to: describe and model gas behavior and how

gases exert pressure their container. Do now: What’s one class where you “fell off”

(or almost did!) recently? At what point in the gradual release model did

you “fall off?” What strategy did you use to “get back on?”

Agenda

I. Do nowII. Gas behavior discussionIII. Be a gas!! Collect and analyze dataHomework: Finish Unit 6 packet

pages 4-5: Fri.Quiz on 5.9

Exit Ticket

Quiz on 5.9 tomorrow!

Properties of Gases

Kinetic Theory

Kinetic Theory: Gas particles are always in constant motion.

Assumptions of Kinetic Theory

1. Gases are composed of separate, tiny particles called molecules

2. Gas molecules are in constant, rapid, straight line motion (which means that gas molecules have kinetic energy)

3. The collisions between molecules are completely elastic (when molecules collide, there is no exchange of energy)

4. The molecules of a gas have no attraction or repulsion for each other

5. Each molecule in a gas has a different velocity

Gases are…

Compressible: There is so much space between gas particles that a sample of gas can be squished into a smaller space!

Gases are…

Expandable: They always take up their entire container!

Modeling Gas Behavior

Unit 6 p. 3 You’re going to be a gas! How will you behave?

When you make a collision with the inside of the flask or a fellow gas particle, say “Ping!” Don’t make any other noise!

Listen CAREFULLY for directions!

Expectations

Listen carefully to directions and follow them closely.

Obey the assumptions of a gas – travel in straight lines, collide elastically, etc.

When you collide, do so gently and responsibly.

Say “Ping!” only when colliding. Have fun and make this work for us!

Graph

1: Temperature vs. “Pings” 2: Flask size vs. “Pings”

Title, axis labels, units, axis scale, plot points, line of best fit

Complete page 5 Then, individually, complete pages

6-7

Homework

Finish Unit 6 packet pages 4-5: Fri. 5.9 Quiz tomorrow

When you were a gas…

You noticed that: As heat increased, particles moved

faster so pressure increased. As the number of moles increased,

there were more collisions, so pressure increased.

As volume decreased, there were more collisions, so pressure increased.

A: 9 March 2012

Take Out Homework: Packet p. 4-5 Objective: You will be able to:

convert between units for temperature, pressure, volume, moles and mass

describe gas behavior and the relationship between pressure and volume.

Do now: Describe gas behavior in 1-2 complete sentences.

Agenda

I. Do nowII. Quiz on 5.9III. Graph analysisIV. Units for gas calculationsV. My life as a gas moleculeVI. Pressure vs. volume labHomework: Finish Unit 6 packet

pages p. 6-14: Tues.

Variables that Affect a Gas

1. Temperature• How much kinetic energy does the gas

have?2. Pressure

• How much force is squeezing on the gas?3. Volume

• How much space does the gas take up?4. number of Moles

• How many atoms or molecules of gas are there?

Temperature

Temperature needs to be in Kelvin K = oC + 273 oC = K – 273

Example: Convert 100oC to Kelvin. 100oC + 273 = 373 K

Example: Convert 393 K to oC. 393 K – 273 = 120oC

Temperature

What if temperature is in oF?

What is 80oF in oC? What is 15oC in oF?

3259

)32(95

CF

FC

Units of Pressure

P = Pressure P must be in atmospheres (atm)

1 atm is the mass of our atmosphere pushing downon you!1 atm = 760 mmHg1 atm = 101.3 kPa1 atm = 14.7 psi

1 atm

Volume

Volume must be in Liters 1000 mL = 1 L

Ex: How many liters are equal to 450 mL?

Ex: How many milliliters are equal to 2.5 L?

Unit Conversions

pages 8-11

My life as a gas molecule

p. 6-7 Write silently – 15 minutes Then, sketch your picture.

I’ll bring around some colored pencils.

or begin working on the homework on p. 10-11

Think about sharing your work!

Pressure vs. Volume Experiment

p. 12-14 – Complete with your partner

Then, work on the homework: p. 8-14

Homework

Unit 6 packet pages p. 6-14: Tues.

C: 9 March 2012

Take Out Homework: Packet p. 6-7 Objective: You will be able to:

show what you know about percent yield and gas units and pressure

develop criteria for graphing data Do now: How many kPa are equal to

850 mmHg?

Agenda

I. Do nowII. Quiz on 5.9III. Reading?IV. Graph criteriaV. Exit tickets on 6.1 and 6.2Homework: Be sure your packet is

complete through page 14!

Graph Criteria

0 5 10 15 20 250

0.5

1

1.5

2

2.5

Volume vs. Pressure of a Gas in a Syringe

Volume (mL)

Pres

sure

(atm

)

In your notebook:

Brainstorm: What are the criteria for an excellent graph?

For example: Title

With your group

Compile a complete list of all the criteria

Criteria for an Excellent GraphABCDEFGHIJ

Rate Your Graph

What criteria did you meet? (Green) What criteria did you fail to meet so

far? (Orange)

Edit your graph so it meets all the criteria.

Complete the analysis questions. Due Monday!

A: 13 March 2012

Take Out Homework: Packet p. 12-14 Objective: You will be able to:

demonstrate your current knowledge of unit conversions and gas behavior

model strategies for effective effort Do now: Calculate: How many kPa are

equal to 850 mmHg?

Agenda

I. Do nowII. Graph interpretation: page 12-14III. Exit tickets on 6.1 and 6.2IV. Clean out folder/notebookV. Effective EffortHomework: Folder check: Weds.Metacog. Worksheet part 3: Weds.

Hand in your packet

p. 12-14 graded

Exit Ticket 6.1 and 6.2

When you finish, begin to organize your notebook and folder.1. Keep in your folder: Unit 6 stuff and

metacognition stuff.2. Your notebook should have NO papers

stuck in it (a periodic table is ok)3. Paperclip Unit 5 stuff together, but

keep at your desk.4. 5 HW points tomorrow for having an

organized folder and notebook!

C: 14 March 2012

Take Out Homework: Open your folder

Objective: You will be able to: relate temperature and volume of

a gas use the gas laws equations to

relate temperature, pressure and volume

Do now: From memory, list two of the things we assume are true about gases. Then check your notes for the answers!

Agenda

I. Do nowII. Track Exit Ticket 6.1 and 6.2III. Gas Laws CalculationsIV. Charles’ Law LabHomework: p. 16, 17, 18 #1-4: Mon. p. 23 #1-4: Mon. Quiz on 6.1 and 6.2 tomorrow.

Track Exit Ticket 6.1 and 6.2

On the front of your Unit 6 Packet! Then, correct your answers.

Solving Gas Laws Problems

How are those variables related?

2

22

1

11

TVP

TVP

This equation is for calculating what happens to a sample of gas if one variable is changed

If you change any one of these variables, all the others will change

If one variable is held constant (not changing) in the equation, it can be crossed out

Pressure and Volume

2

22

1

11

TVP

TVP

Let’s say we hold temperature constant That is, we don’t allow temperature to

change. If we increase pressure, volume will

decrease. If we decrease pressure, volume will

increase.

Pressure and Volume

At the earth’s surface, the volume of a balloon is 2.0 liters. If temperature remains constant, calculate the new volume if the balloon is submerged underwater 100 feet, where there is pressure of about 4 atmospheres.

P1V1=P2V2

pressure on earth’s surface = 1 atm

1 atm∙2.0L=4 atm ∙V2

2 = 4 V2

divide both sides by 4 V2 = 0.5 L

The volume will decrease to 0.5 L!

2

22

1

11

TVP

TVP

Volume and Temperature

2

22

1

11

TVP

TVP

Let’s say we hold pressure constant That is, we don’t allow pressure to

change. If we increase volume, temperature will

also increase. If we decrease volume, temperature will

also decrease.

Volume and Temperature

A balloon, at room temperature (20oC), has a volume of 2.0 L. The balloon is gently heated until the gas inside it is 80oC. If pressure stays constant, calculate the new volume of the balloon.

20oC + 273 = 293 K80oC + 273 = 353 K

multiply both sides by 353.

2

22

1

11

TVP

TVP

2

2

1

1

TV

TV

KV

KL

3532930.2 2

KV353

0068.0 2

LV 4.22

Pressure and Temperature

2

22

1

11

TVP

TVP

Let’s say we hold volume constant That is, we don’t allow volume to

change. If we increase pressure, temperature

will also increase. If we decrease pressure, temperature

will also decrease.

Pressure and Temperature

A can of hairspray has an internal pressure 2 atmospheres at room temperature (20oC). If the can is placed near the heater and the temperature increases to 50oC, what is the new pressure inside the can, if the volume of the can stays constant?

20oC + 273 = 293 K50oC + 273 = 323 K

multiply both sides by 323.

2

22

1

11

TVP

TVP

2

2

1

1

TP

TP

KP

Katm

3232930.2 2

KP323

0068.0 2

atmP 2.22

Charles’ Law Lab p. 15

It’s not cold outside. (Yay!) But we need a cold place to do this

lab… Faculty room freezer! We’ll work on the procedure as a

class, then you’ll work with your group to complete the graph, analysis and conclusions.

Due tomorrow!

C: Homework due Mon. 3/19

p. 16, 17, 18 #1-4 p. 23 #1-4

Quiz tomorrow on 6.1 and 6.2

A: Homework due Fri. 3/16

p. 16, 17, 18 #1-4 p. 23 #1-4

Practice Problems

1. P1 = 1.0 atm P2 = 3.0 atmV1 = 200 mL V2 =

2. V1 = 4 L V2 = 1 LT1 = 30oC T2 = ?

3. P1 = 800 mmHg P2 = ?T1 = 0oC T2 = −25oC

Word Problems

1. A helium balloon at 1.0 atmosphere at 25oC has a volume of 2.0 liters. If the balloon is brought up into the air where the pressure is 0.80 atmospheres, calculate the new volume, assuming that the temperature remains constant.

2. A can of hairspray has an internal pressure of 3.00 atm at 25oC. Calculate the new internal pressure if the temperature of the can is rasied to 100oC.

Homework

p. 15-19, 22-24: Thurs.

C: 15 March 2012

Objective: You will be able to: solve gas laws problems manipulate and make observations about a

sample of gas Do now: You have two balloons of the same

volume. You leave one on your desk, but tie the other one to the wing of an airplane that then flies 14,000 feet into the atmosphere. Which balloon has the greater volume assuming the temperatures are the same? Why?

Agenda

I. Do nowII. Quiz on 6.1 and 6.2III. Using the gas laws equations examplesIV. Practice ProblemsV. Gases computer simulationHomework: p. 16, 17, 18#1-4: Mon.p. 22, p. 23 #5-6, p. 24 #7-8, p. 30-

34 all: Mon

A: 15 March 2012

Objective: You will be able to: solve gas laws problems using the

combined gas law and the ideal gas law. Do now: You have two balloons of the

same size. You leave one on your desk, but tie the other one to the wing of an airplane that then flies 14,000 feet into the atmosphere. Which balloon has the greater volume assuming the temperatures are the same? Why?

Agenda

I. Do nowII. Quiz on 6.1 and 6.2III. Using the gas laws equations

examplesIV. Practice ProblemsHomework: p. 16, 17, 18#1-4: Fri..p. 22, p. 23 #5-6, p. 24 #7-8, p. 30-

34 all: Fri.

Quiz

When you finish, turn it in. Then, complete p. 23 #1-6

Combined Gas Laws

With your partner, complete p. 25-26

A: 16 March 2012 Take Out: p. 25 Objective: You will be able to:

solve gas laws problems using the ideal gas law.

manipulate V, T, P and n, and make observations and calculations.

Do now: A 0.50 liter can of hairspray is at room temperature (20oC) and standard pressure. If I place the can in the oven (200oC), what will the pressure inside the can be?

If the can of hairspray can withstand an internal pressure of 1140 mmHg, will the can explode?

Agenda

I. Do nowII. Using the ideal gas law equation:

examplesIII. Practice ProblemsIV. Gas laws computer simulationHomework: p. 28-29, 31-32: Tues.

P, V and T

can be related in a slightly different equation along with number of moles

Can be used if the conditions aren’t changing (that is, P, V, and T are staying the same)

How are P, V, T and number of moles (n) related?

Ideal Gas Law: PV=nRT P = Pressure V = Volume n = number of moles R = constant T = Temperature

What do you need to know about PV=nRT?

R is the gas constant

It is the same for every gas in every problem!

KmolatmL

0821.0

Standard Temperature and Pressure (STP)

Standard Temperature: OoC =273 K

Standard Pressure: 1 atm

Problems often state “standard temperature and pressure” or “at STP”

Example problems

using the combined gas law

PV=nRT

What is the volume of 2.0 moles of gas at standard temperature and pressure?

nRTPV K

KmolatmLmolVatm 2730821.00.21

LV 8.44

PV=nRT

At what temperature will 1.0 mole of gas at 2 atmospheres occupy a volume of 20 liters?

nRTPV T

KmolatmLmolLatm

0821.00.1202

T 0821.040KT 487

CK o214273487

Practice Problems

p. 24, 28, 29

Practice Problems

1. A container with rigid sides has a volume of 2.0 liters. It is filled with 3.0 moles of oxygen gas at 25oC. Calculate the pressure inside the container in atm and in mmHg.

2. A balloon at 70oC is filled with helium gas. The volume of the balloon is 5.0 liters at 1.00 atmosphere. How many moles of helium must be in the balloon? How many grams of helium is this?

Computer Simulation

p. 20-21 First, make some changes… Work with your partner; share one laptop. Log on to the website, and follow the

directions. Record your observations carefully and

completely! Then, do the practice problems. Due at the end of the period!

C: Homework: due Monday

p. 16, 17, 18#1-4: Mon.p. 22, p. 23 #5-6, p. 24 #7-8, p.

30-34 all: Mon

Need extra help? I’ll be here until 4:00 on Friday in Room 203!

A: Homework: due Fri.

p. 16, 17, 18#1-4: Fri.p. 22, p. 23 #5-6, p. 24 #7-8, p.

30-34 all: Fri.

Need extra help? I’ll be here until 4:00 on Friday in Room 203!

A: 20 March 2012

Take Out Homework: Turn to p. 31 Objective: You will be able to:

experimentally determine R (the gas constant)!

Do now: Calculate the number of moles of oxygen gas required to fill a 2.0 liter flask at STP.

How many molecules of oxygen is this?

Agenda

I. Do nowII. Go over homework p. 30-34III. Exit ticket on 6.3 and 6.4IV. Determining R experimentallyV. Hand in packet (p. 12-21 = three

lab grades!)Homework: Quiz on 6.3 and 6.4

Friday

Exit Ticket

When you finish, turn it in. Then, read p. 36 of the Unit 6

packet.

Determining R Lab

If you can measure P, V, n and T… You can calculate R!!

Our gas…

A butane lighter (formula?) This lab doesn’t involve a flame. Please don’t waste your butane by

“flicking the Bic” until it’s under water

Demonstration

steps 5-9 watch carefully! Dry the lighter before re-weighing.

During the lab

Stay at your station. Work carefully and efficiently. Read each step twice, and follow it

exactly!! Record your data as you collect it.

Before you go

Leave your packet on the kidney table!

Homework: 6.3 and 6.4 Quiz Friday