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 • Do now • Go over homework answers • Percent yield exit ticket • Properties of a gas notes • Be a gas!! Collect and analyze data Homework: 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 • Do now • Gas behavior discussion • Be a gas!! Collect and analyze data Homework: Finish Unit 6 packet pages 4-5: Fri. Quiz on 5.9
Exit Ticket • Quiz on 5.9 tomorrow!
Kinetic Theory • Kinetic Theory: Gas particles are always in constant motion.
Assumptions of Kinetic Theory • Gases are composed of separate, tiny particles called molecules • Gas molecules are in constant, rapid, straight line motion (which means that gas molecules have kinetic energy) • The collisions between molecules are completely elastic (when molecules collide, there is no exchange of energy) • The molecules of a gas have no attraction or repulsion for each other • 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 • Do now • Quiz on 5.9 • Graph analysis • Units for gas calculations • My life as a gas molecule • Pressure vs. volume lab Homework: Finish Unit 6 packet pages p. 6-14: Tues.
Variables that Affect a Gas • Temperature • How much kinetic energy does the gas have? • Pressure • How much force is squeezing on the gas? • Volume • How much space does the gas take up? • 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?
Units of Pressure 1 atm • P = Pressure • P must be in atmospheres (atm) • 1 atm is the mass of our atmosphere pushing down on you! 1 atm = 760 mmHg 1 atm = 101.3 kPa 1 atm = 14.7 psi
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 • Do now • Quiz on 5.9 • Reading? • Graph criteria • Exit tickets on 6.1 and 6.2 Homework: Be sure your packet is complete through page 14!
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
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 • Do now • Graph interpretation: page 12-14 • Exit tickets on 6.1 and 6.2 • Clean out folder/notebook • Effective Effort Homework: 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. • Keep in your folder: Unit 6 stuff and metacognition stuff. • Your notebook should have NO papers stuck in it (a periodic table is ok) • Paperclip Unit 5 stuff together, but keep at your desk. • 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 • Do now • Track Exit Ticket 6.1 and 6.2 • Gas Laws Calculations • Charles’ Law Lab Homework: • 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.
How are those variables related? • 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 • 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!
Volume and Temperature • 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 K 80oC + 273 = 353 K multiply both sides by 353.
Pressure and Temperature • 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 K 50oC + 273 = 323 K multiply both sides by 323.
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!