# GAS LAWS WARM UP Take out your notebook

GAS LAWS

WARM UP Take out your notebook. Write the Unit topic (Gas Laws) on a new page. Copy down these topic objectives. UNIT 6 OBJECTIVES: At the end of this unit I will be able to: v Explain the relationships among pressure, temperature, volume, and quantity of gas – both qualitative and quantitative

AGENDA EQ: How do different variables (volume, pressure, temperature, number of particles) affect the movement of gases? WARM UP v ANNOUNCEMEN TS v DATA TRACKING / RETESTING v UNIT 6 INTRO v � VOCABULARY � BASIC v CONCEPTS KINETIC

ANNOUNCEMENTS All missing assignments are now OVERDUE!!!

That means (from the curriculum) we should be able to: Identify characteristics of ideal gases. Apply general gas solubility characteristics. Apply the following formulas and concepts of kinetic molecular theory. 1. 2. 3. 4. 5. 1 mole of any gas at STP=22. 4 L Ideal gas equation (PV=n. RT), Combined gas law (P 1 V 1/T 1 = P 2 V 2/T 2) and applications holding one variable constant: for PV=k, P 1 V 1 = P 2 V 2; for V/T=k, V 1/T 1= V 2/T 2; for P/T=k, P 1/T 1 = P 2/T 2. Note: Students should be able to derive and use these gas laws, but are not necessarily expected to memorize their names. Avogadro’s law (n/V=k), n 1/V 1 = n 1/V 2 Dalton’s law (Pt=P 1+P 2+P 3 …) Vapor pressure of water as a function of temperature (conceptually).

Sooooo… Yessss…it’s a lot of math, but it’s also a lot of fun stuff like: � Crushing a soda can using water � Inflating balloons without blowing them up � Figuring out how to change a gas to a liquid without cooling it down

UNIT 6 SUBTOPIC 1: THE KINETIC MOLECULAR THEORY - Diffusion States of matter

MATTER All matter is made up of extremely tiny particles (atoms, molecules, etc). There are three states of matter. They are solid, liquid and gases. Particles are constantly moving

Particle Movement Demo Our aim is to observe how particles move. At your stations: � Place one drop of dye in each beaker of water. � Observe how the color spreads through the water.

Kinetic Molecular Theory: Gas particles… � are moving constantly and their movement is random. � bump into each other and that collision affects how and where they move. The collisions transfer motion and energy When heat energy is added to a system, the temperature AND speed of the particles increase.

Unit 6 Worksheet 1 QUIETLY, Answer questions 1 -3.

PRESSURE – a force caused by the collisions between gas particles and the sides of their container How does pressure cause this to happen? http: //www. youtube. com/watch? v=Bi 6 s DTXE 9 TE

So what is the relationship between pressure, volume and number of particles? Gas Laws Demo Pay careful attention and make notes. �Party Time, Excellent: Pressure vs Number of Particles �Hot Air Ballooning: Pressure vs Temperature �Amazing Marshmallows:

Party Time, Excellent: Pressure vs Number of Particles Compare the number of particles before and after the demonstration. Has the number of particles increased or decreased? Has pressure increased or decreased? What is the relationship between pressure and number of particles?

Hot Air Ballooning: Pressure vs Temperature What happens to the balloon as temperature increases? What is the relationship between pressure and temperature?

Amazing Marshmallows: Pressure vs Volume What happens to the volume of the marshmallow as we increase pressure (pushing the syringe down)? What happens to the volume of the marshmallow as we decrease the pressure (pulling the syringe up)?

Consensus: (Copy the annotated diagrams. ) When the # of particles increases, pressure increases. When temperature increases, Pressure increases. When volume increases, Pressure decreases.

Exit Quiz If temperature increases, what happens to the state of matter of a solid? If volume decreases, what happens to the state of matter of a liquid? If pressure increases, what happens to the state of matter of a liquid?

WARM UP Do question 1 on the worksheet you received as you came in to class. Mole boxes on the front desk please!!!

Review Of Yesterday Solid vs. Liquid vs. Gas � Describe Particle Movement Temperature effects Kinetic Molecular Theory � Gas particle movement � Particle interaction � Heat

Review Cont. Expansion and Contraction: Matter heats up Moves faster EXPANDS Takes up more space Matter cools down Moves slower CONTRACTS Takes up less space The hotter molecules get, the faster molecules move, the further apart they move from each other. Thermometers: http: //www. youtube. com/watch? v=n. CQVTTKu 0 Xc

WARM UP Collect your progress report, a test and a data analysis sheet. Complete both sides of your data analysis sheet. Staple your test and data analysis sheet together. Make sure to turn in your missing work!!!

AGENDA EQ: How do different variables (volume, pressure, temperature, number of particles) affect the movement of gases? WARM UP v ANNOUNCEMEN TS v DATA TRACKING v PRESSURE CONVERSIONS v GAS LAWS v v COMBINED LAW GAS

ANNOUNCEMENTS All missing assignments are now OVERDUE!!!

Consensus When drum is heated, the water inside heats up and evaporates to form water vapor. When the drum is placed in ice, the water vapor quickly condenses into liquid water. The rapid condensation reduces the pressure in the drum and the atmospheric pressure is so much greater that it crushes the drum!! Atmospheric pressure = the pressure exerted by the atmosphere

Volume, Pressure and Temperature Activity Have one member from your group collect the activity sheet from my desk. Complete all activities on the sheet When you get to the section where heat is needed, come to my desk.

How do we measure pressure? (Gas Conversions) There are several units for pressure, and we can use their equal values to convert from one to the next. These units include:

Gas Units k. Pa kilopascals � torr Torr � Sea level is 1 atm mm. Hg millimeters of Mercury � Named after the Italian scientist Evangelista Torricelli atmospheres � Used frequently by meteorologists Hg is the atomic symbol for Mercury psi pounds per square inch � This is what is usually used to measure the air pressure in a car tire!

How do they relate? WRITE THESE IN YOUR NOTES!! 1 atm = 760 torr = 101. 325 k. Pa = 760 mm. Hg = 14. 7 psi

Got it? Let’s use the values you just copied to convert! DIMENSIONAL ANALYSIS!!! (Just like 1 -step conversions!) EXAMPLE: Convert 12 psi to torr. Step 1 – Write out your units for a conversion Step 2 – Fill in the numbers THAT’S IT!

Still scratching your head? Convert 2. 2 atm to k. Pa. Step 1 – Write out your units for a conversion Step 2 – Fill in the numbers

A FEW MORE, REALLY I PROMISE Convert 844 torr to atm: Convert 10, 450, 217 mm. Hg to torr:

You try! Answer questions 5 & 6 on Unit 6 Worksheet 1. Do this individually and do not talk to anyone else!

WARM UP Convert 3 atm to: �Torr �k. Pa �Psi �mm. Hg 1 atm = 760 torr = 101. 325 k. Pa = 760 mm. Hg = 14. 7 psi

AGENDA EQ: How do different variables (volume, pressure, temperature, number of particles) affect the movement of gases? WARM UP v ANNOUNCEMEN TS v GAS LAWS v v COMBINED GAS LAW v IDEAL GAS LAW

ANNOUNCEMENTS Grades may not necessarily be uploaded because of a Power. School glitch. Keep checking back. Yes!!! I am still collecting missing work!!! TURN IT IN! Remember the PATCH program? They are looking for male juniors. Visit my website to apply.

Now, how can we determine numerically what the pressure or volume or temperature of a system is? Use the Gas Laws (see your pink sheet): � Charles Law, � Boyle’s Law � Ideal Gas Law � Combined Gas Law � etc

Notes: Combined Gas Law Four variables used in gas law problems: V = volume of the gas (L) T = temperature (K) �K stands for Kelvin. �K = o. C+273 n = number of particles (moles) P = pressure (atmospheres)

Notes: Combined Gas Law Earlier, we found the relationship between all these variables. 1) Pressure and Temperature are POSITIVELY related (when one goes up, so does the other). 2) Pressure and the number of particles (n) are POSITIVELY related. 3) Pressure and volume are NEGATIVELY related (when one goes up, the other goes down)!!

What does this all boil down to? THE COMBINED GAS LAW!!! ALERT!! T must ALWAYS be in Degrees KELVIN (ie celsius +273)

Process of solving a problem Step 1: Identify which variables the problem gives you. � For some problems this will be easy, but you really have to look through word problems!! Clues—First: initial, beginning, start Clues—Second: then, secondly, after, new Look for the verb! If something is happening, you have a _____ then ______ situation. Step 2: Cross out any variables you don’t need Step 3: Solve the remaining equation

Examples The pressure inside of a 5. 1 L container is 3. 2 atm. The container expands to a volume of 8. 8 L. What is the new pressure inside the balloon? 1) P 1 = 3. 2 atm V 1 = 5. 1 L P 2 = ? V 2 = 8. 8 L Step 1: Identify which variables the problem gives you. Step 2: Cross out any variables you don’t need Step 3: Solve the remaining equation

Examples Bria has a 3. 2 L balloon of hydrogen gas at 23 C. She leaves the balloon in her blazing hot car, and the temperature increases to 72 C. What is the new volume of the balloon? 1) V 1 = 3. 2 L T 1= 23 C V 2 = ? T 2 = 72 C You must convert to Kelvin!!!

Partner Practice The pressure inside a 0. 83 L hot air balloon is 4. 31 atm. If the volume increases to 1. 44 L, what is the new pressure inside the balloon? P 1 = 4. 31 atm V 1 =. 83 L P 2 = ? V 2 = 1. 44 L

Partner Practice A sample of gas occupies of volume of 5. 5 L. After being compressed to a volume of 3. 9 L, the new temperature of the sample of gas is 273 K. What was the initial temperature of the gas? V 1 = 5. 5 L T 1= ? V 2 = 3. 9 L T 2 = 273 K

You try! Do #1 -7 on Unit 6 Worksheet 2

WARM UP The temperature inside my refrigerator is about 40 Celsius. If I place a balloon in my fridge that initially has a temperature of 220 C, a volume of 0. 5 liters, and a pressure of 3 atm, what will be the volume of the balloon when the pressure decreases to 2 atm and the temperature decreases to 40 Celsius? V 1 = 0. 5 L P 2=2 atm T 1=220 C P 1= 3 atm V 2 = ? T 2 = 40 C

AGENDA EQ: How do different variables (volume, pressure, temperature, number of particles) affect the movement of gases? WARM UP v ANNOUNCEMEN TS v GAS LAWS v v COMBINED GAS LAW v IDEAL GAS LAW

ANNOUNCEMENTS Grades may not necessarily be uploaded because of a Power. School glitch. Keep checking back. Yes!!! I am still collecting missing work!!! TURN IT IN! Remember the PATCH program? They are looking for male juniors. Visit my website to apply.

Last time we looked at: The combined gas law: Today we look at the IDEAL GAS LAW.

Notes: Ideal Gas Law PV = n. RT “piv nert” This equation is used to predict any of these variables when the others are held constant. • • • P = pressure (atm) V = volume (L) n = number of particles (moles) T = temperature (KELVIN!) R = gas constant - 0. 0821 L atm /mole K OR - 8. 31 L k. Pa / mole K OR - 62. 4 L mm. Hg / mole K

When Do I Use Which? Use “Ideal Gas Law” when solving for a variable and everything is held constant… used “Combined Gas Law” when something is changing and you are asked for “new” pressure, for example. Think Combined … Change

Let me show you: . 89 moles of a colorless gas occupy a volume of 84. 1 L and a pressure of 3. 6 atm. What is the temperature of the gas?

Individual Practice If I have an unknown quantity of gas held at a temperature of 1195 K in a container with a volume of 25 liters and a pressure of 560 atm, how many moles of gas do I have?

Partner Practice If I have 8 moles of a gas at a pressure of 1. 6 atm and a volume of 6 L, what is the temperature?

WARM UP 1. 2. 3. 15 MINUTES A sample of gas at 288 K occupies a volume of 65 L. The gas is compressed to a volume of 48 L. What is the new temperature of the gas? How many torr are there in 304 k. Pa? If I have 4 moles of a gas at a pressure of 1. 6 atm and a volume of 6 L, what is the temperature? PV = n. RT 1 atm = 760 torr = 101. 325 k. Pa = 760 mm. Hg = 14. 7 psi

AGENDA EQ: How do different variables (volume, pressure, temperature, number of particles) affect the movement of gases? WARM UP v ANNOUNCEMEN TS v PROJECT!!! v GAS LAWS v v DALTON’S LAW v GAS STOICHIOMETRY

ANNOUNCEMENTS I am still collecting missing work!!! TURN IT IN! Tomorrow’s tutoring starts at 3 pm and ends at 3: 30 (I have a meeting after school). Thursday’s tutoring will be the regular time: 2: 30 – 3: 30. Would you like to be a PTSA ambassador? See me during the break

SCHEDULE FOR NEXT 7 DAYS: Monday 11. 16: § Dalton’s Law; Applications; Practice Tuesday 11. 17: Wednesday 11. 18: Thursday 11. 19: -4 Friday 11. 20: Monday 11. 23: Review Unit 6 Test Unit 6 Review Units 1 Review Unit 5 CIA Cycle 3

PROJECT: SCIENTIFIC DIVERSITY Due: Monday 11. 30. 15 Create a product highlighting a scientist from a country that you are connected to (your birth country, USA, your parents’ birth country, etc). Your product should include: � The scientist’s name; � A picture of the scientist; � The scientist’s country and flag of that country � The scientist’s major accomplishments / research;

Notes: Partial Pressure IT’S NOTES TIME!!! Dalton's Law of Partial Pressure = The pressure of a mixture of gases is equal to the sum of the pressures of all of the individual gases alone. Pressure. Total = Pressure 1 + Pressure 2. . . Pressuren

HONORS ONLY: Partial Pressure & Moles 1. A container holds three gases: oxygen, carbon dioxide, and helium. The partial pressures of the three gases are 2. 00 atm, 3. 00 atm, and 4. 00 atm, respectively. What is the total pressure inside the container? 2. A container with two gases, helium and argon, is 30. 0% by volume helium. Calculate the partial pressure of helium and argon if the total pressure inside the container is 4. 00 atm. 3. A tank contains 480. 0 grams of oxygen and 80. 00 grams of helium at a total pressure of 7. 00 atmospheres. Calculate the following 1. 2. 3. 4. 5. 6. 7. How many moles of O 2 are in the tank? How many moles of He are in the tank? Total moles of gas in tank. Mole fraction of O 2. Mole fraction of He. Partial pressure of O 2. Partial pressure of He.

HONORS ONLY: Gas Stoichiometry 1. Ammonium sulfate, an important fertilizer, can be prepared by the reaction of ammonia with sulfuric acid according to the following balanced equation: 2 NH 3 (g) + H 2 SO 4 (NH 4)2 SO 4 (aq) Calculate the volume of NH 3 (in liters) needed at 20ºC and 25. 0 atm to react with 150 kg of H 2 SO 4. 2. If 45. 0 L of natural gas, which is essentially methane (CH 4), undergoes complete combustion at 2 atm and 20ºC, how many grams of each product

LET’S PRACTICE: Unit 6 Worksheet 5. Work in groups, on your own, or up front with me. Whatever you choose, make sure that I cannot hear your group’s voices. Turn in the completed worksheet at the end of class.

WARM UP 15 MINUTES 1. 2. 3. 4. A sample of gas at 144 K occupies a volume of 5 L. The gas is compressed to a volume of 3 L. What is the new temperature of the gas? How many torr are there in 152 k. Pa? If I have 2 moles of a gas at a pressure of 16 atm and a volume of 3 L, what is the temperature? What is the total pressure of a container with equal amounts of hydrogen and nitrogen if the nitrogen has a pressure of 3 atm? Pressure total = P 1 + P 2 + P 3…Pn PV = n. RT 1 atm = 760 torr = 101. 325 k. Pa = 760 mm. Hg = 14. 7 psi

AGENDA EQ: How do different variables (volume, pressure, temperature, number of particles) affect the movement of gases? WARM UP v ANNOUNCEMEN TS v REVIEW & 1 -on-1 MEETINGS v v Topic Review v Practice

ANNOUNCEMENTS I am still collecting missing work!!! TURN IT IN! Today’s tutoring starts at 3 pm and ends at 3: 30 (I have a meeting after school). Thursday’s tutoring will be the regular time: 2: 30 – 3: 30. Would you like to be a PTSA ambassador? See me for details.

ANNOUNCEMENTS U 6 (Gas Laws) Test tomorrow. CIA Cycle 3 Test Monday

REVIEW PART 1: Follow the instructions on your group’s paper to complete a topic review. You will be presenting to the class after 15 minutes.

REVIEW PART 2: Visit each station Complete at least 3 questions from each station. You may get help from your classmates if you get stuck. I will be meeting with you to discuss your progress while you do your review.

WARM UP 15 MINUTES 1. 2. 3. 4. P 1=6 atm V 1=65 L T 1=15 o. C P 2=3 atm V 2=30 L T 2=? ? ? What is the pressure inside a 55 L container with 3 moles of gas at a temperature of 35 o. C? How many psi are there in 10 atm? What is the total pressure inside a 2 L container at 300 K where there are equal amounts of 3 gases, each having a pressure of 7 atm? Pressure total = P 1 + P 2 + P 3…Pn

WARM UP 15 MINUTES 1. 2. P 1=600 torr V 1=65 L T 1=15 o. C P 2=300 torr V 2=30 L T 2=? ? ? (Hint: Convert torr to atm first. ) A mixture of gases contains 0. 5 moles of Neon, 0. 396 moles of Argon and 0. 714 moles of Xenon. Calculate the partial pressure of the gases if the total pressure is 2 atm at a certain temperature. (Hint: Use mole fractions. ) Pressure total = P 1 + P 2 + P 3…Pn PV = n. RT 1 atm = 760 torr = 101. 325 k. Pa = 760 mm. Hg = 14. 7 psi

AGENDA EQ: How do different variables (volume, pressure, temperature, number of particles) affect the movement of gases? WARM UP v ANNOUNCEMEN TS v SYRIAN REFUGEES v TEST v

ANNOUNCEMENTS I am still collecting missing work!!! TURN IT IN! Thursday’s tutoring will be the regular time: 2: 30 – 3: 30. If you are interested in working as a Vance PTSA Ambassador, please collect the application form from me. Also let me know what lunch you have. We will start working tomorrow during lunches. Remember: �CIA Cycle 3 Test: Monday 11. 23. 15

TEST DAY!!! No communication between students. No phones are allowed (no headphones either – I should not see your phone out). You may use the pink reference sheets, pencils / pens, and nothing else! Write all your answers on the question paper.

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