CH301 Vanden Bout/LaBrake Fall 2013
VandenBout/LaBrake/Crawford
CH301
GAS LAWS - Day 3
CH301 Vanden Bout/LaBrake Fall 2013
Important Information
HW2 POSTED - DUE TUE MORNING 9AMLM6 & 7 POSTED – DUE TUE MORNING 9AM
LM2,3,4 & 5 WERE DUE THIS MORNING 9AM
Unit1Day3-LaBrakeWednesday, September 04, 20135:19 PM
Unit1Day3-LaBrake Page 1
CH301 Vanden Bout/LaBrake Fall 2013
What are we going to learn today?
MACROSCOPIC & MICROSCOPIC VIEWS OF GASESIDEAL GAS LAW
USE IDEAL GAS LAW – IDENTIFY UNKOWN GAS
CH301 Vanden Bout/LaBrake Fall 2013
QUIZ: CLICKER QUESTION 1 (points for CORRECT answer)
According to Avagadro’s Law, a sample of H2
gas with a volume of 10 liters, at a pressure of 2 atm, and a temperature of 25°C, contains ________ “particles” compared to a sample He gas that has a volume of 5 L at the same temperature and pressure.
A. the same number ofB. two times moreC. four times moreD. two times lessE. four times less
CH301 Vanden Bout/LaBrake Fal 2013
Which of the following is a plot of the pressure of a gas as a function of the volume at fixed temperature?
QUIZ: CLICKER QUESTION 2 (points for CORRECT answer)
A B
C D
Unit1Day3-LaBrake Page 2
CH301 Vanden Bout/LaBrake Fal 2013
Which of the following is a plot of the pressure of a gas as a function of the volume at fixed temperature?
QUIZ: CLICKER QUESTION 2 (points for CORRECT answer)
A B
C D
CH301 Vanden Bout/LaBrake Fall 2013
Describe a Gas
PHYSICAL DESCRIPTION:
VOLUMEPRESSURE – most abstract property
TEMPERATUREAMOUNT
GAS LAWs QUANTIFY THE RELATIONSHIP OF THE PROPERTIES. EQUATION FORM OF LAWs GIVE
ABILITY TO PREDICT CONDITIONS AT NEW STATE
Unit1Day3-LaBrake Page 3
CH302 Vanden Bout/LaBrake Spring 2012
You have a sample of O2 gas T = 10°C and a P = 1 atm. If you increase T = 20°C and keep P = 1 atm, V will:
A. stay the sameB. be slightly higher but not double the originalC. double compared to the original volumeD. decrease slightly but not in half the originalE. decrease to half the original volume
POLL: CLICKER QUESTION 3
CH301 Vanden Bout/LaBrake Fall 2013
TRY IT - Balloon in ice water… balloon in liquid N2
CH301 Vanden Bout/LaBrake Fall 2013
COMPARE COLD BALLOON TO BALLOON IN VACUUM
COMPARE MACROSCOPIC VIEW WITH MICROSCOPIC VIEW
http://ch301.cm.utexas.edu/simulations/gas-laws/GasLawSimulator.swf
Unit1Day3-LaBrake Page 4
CH301 Vanden Bout/LaBrake Fall 2013
COMPARE COLD BALLOON TO BALLOON IN VACUUM
COMPARE MACROSCOPIC VIEW WITH MICROSCOPIC VIEW
http://ch301.cm.utexas.edu/simulations/gas-laws/GasLawSimulator.swf
CH301 Vanden Bout/LaBrake Fall 2013
Think back to the syringe investigation: When the VOLUME of the container is DECREASED, and the T and amount of gas remains the same, the PRESSURE:
a)PRESSURE INCREASESb)PRESSURE DOES NOT CHANGEc)PRESSURE DECREASESd)PRESSURE WILL CHANGE BRIEFLY, BUT THEN RETURNS TO ORIGINAL PRESSURE
POLLING: CLICKER QUESTION 4
CH301 Vanden Bout/LaBrake Fall 2013
Think back to the syringe investigation: When the VOLUME of the container is DECREASED, and the T and amount of gas remains the same, the PRESSURE INCREASES. The small particle explanation is because the:
a)# of collisions INCREASESb)# of collisions DOES NOT CHANGEc)# of collisions DECREASESd)Avg speed of particles DECREASESe)Avg speed of particles DOES NOT CHANGE
POLLING: CLICKER QUESTION 5
Unit1Day3-LaBrake Page 5
CH301 Vanden Bout/LaBrake Fall 2013
Think back to the syringe investigation: When the VOLUME of the container is DECREASED, and the T and amount of gas remains the same, the PRESSURE INCREASES. The small particle explanation is because the:
a)# of collisions INCREASESb)# of collisions DOES NOT CHANGEc)# of collisions DECREASESd)Avg speed of particles DECREASESe)Avg speed of particles DOES NOT CHANGE
POLLING: CLICKER QUESTION 5
CH301 Vanden Bout/LaBrake Fall 2013
Think back to the balloon in liquid N2 demonstration : When the TEMPERATURE of the container is DECREASED, and the P and amount of gas remains the same, the :
a)VOLUME INCREASESb)VOLUME DOES NOT CHANGEc)VOLUME DECREASESd)VOLUME WILL CHANGE BRIEFLY, BUT THEN RETURNS TO ORIGINAL VOLUME
POLLING: CLICKER QUESTION 6
Unit1Day3-LaBrake Page 6
CH301 Vanden Bout/LaBrake Fall 2013
Think back to the balloon in liquid N2 demonstration : When the TEMPERATURE of the container is DECREASED, and the P and amount of gas remains the same, THE VOLUME DECREASES - the small gas particle explanation is because the:
a)AVG SPEED OF PARTICLES DECREASESb)AVG SPEED OF PARTICLES INCREASESc)AVG SPEED OF PARTICLES DOES NOT CHANGE
POLLING: CLICKER QUESTION 7
CH301 Vanden Bout/LaBrake Fall 2013
MACROSCOPIC DESCRIPTION
MICROSCOPIC MODEL (SMALL PARTICLE MODEL)
EMPERICALLY DERIVED MODELS
CH302 Vanden Bout/LaBrake Spring 2012
COMBINE GAS LAWS – IDEAL GAS LAW
PV = nRT
The value of R depends on the units of
measure used for the State Functions
R = .08205746 L atm K−1 mol−1
R = .08314472 L bar K−1 mol−1
Unit1Day3-LaBrake Page 7
CH302 Vanden Bout/LaBrake Spring 2012
COMBINE GAS LAWS – IDEAL GAS LAW
PV = nRT
The value of R depends on the units of
measure used for the State Functions
R = .08205746 L atm K−1 mol−1
R = .08314472 L bar K−1 mol−1
CH301 Vanden Bout/LaBrake Fall 2013
COMBINE GAS LAWS – IDEAL GAS EQUATION
PV = nRT
THIS IS ACTUALLY QUITE COOL
CH301 Vanden Bout/LaBrake Fall 2013
USEFULLNESS?
PV = nRT
Given 3 properties of the state, calculate the 4th.
Predicts every single gas should have the same number density.
Same P, T should be identical – moles per volume (# density).
Molar volume – volume per one mole useful for gas stoichiometry.
Particles have different masses, different gases should have different
mass densities under same conditions.
Given P, T and molar mass – calculate mass density of a gas.
Given P, T and density – calculate the molar mass of a gas.
Unit1Day3-LaBrake Page 8
CH301 Vanden Bout/LaBrake Fall 2013
USEFULLNESS?
PV = nRT
Given 3 properties of the state, calculate the 4th.
Predicts every single gas should have the same number density.
Same P, T should be identical – moles per volume (# density).
Molar volume – volume per one mole useful for gas stoichiometry.
Particles have different masses, different gases should have different
mass densities under same conditions.
Given P, T and molar mass – calculate mass density of a gas.
Given P, T and density – calculate the molar mass of a gas.
CH301 Vanden Bout/LaBrake Fall 2013
POLLING: CLICKER QUESTION 9
Which balloon has the higher mass density?
A. ArB. HeC. they are the same
Unit1Day3-LaBrake Page 9
CH301 Vanden Bout/LaBrake Fall 2013
POLLING: CLICKER QUESTION 9
Which balloon has the higher number density?
A. ArB. HeC. they are the same
CH301 Vanden Bout/LaBrake Fall 2013
POLLING: CLICKER QUESTION 10
We have two identical containers held at the same T, one contains Ar, one contains He. The containers have the same mass density. Which has the higher pressure?
A. ArB. HeC. they are the same
Unit1Day3-LaBrake Page 10
CH301 Vanden Bout/LaBrake Fall 2013
GROUP WORK
Starting with the ideal gas law and the molar mass of a gas, derive an equation
for the mass density of a gas.
CH302 Vanden Bout/LaBrake Spring 2012
CH301 Vanden Bout/LaBrake Fall 2013
GROUP WORK
The oil produced from eucalyptus leaves contains the volatile organic compound eucalyptol. At 190 ºC and 60.0 Torr, a sample of eucalyptol vapor had a density of 0.320 g*L-1. Calculate the molar mass of eucalyptol. Unit1Day3-LaBrake Page 11
CH301 Vanden Bout/LaBrake Fall 2013
GROUP WORK
The oil produced from eucalyptus leaves contains the volatile organic compound eucalyptol. At 190 ºC and 60.0 Torr, a sample of eucalyptol vapor had a density of 0.320 g*L-1. Calculate the molar mass of eucalyptol.
CH301 Vanden Bout/LaBrake Fall 2013
GROUP WORK QUIZ CLICKER QUESTION
The oil produced from eucalyptus leaves contains the volatile organic compound eucalyptol. At 190 ºC and 60.0 Torr, a sample of eucalyptol vapor had a density of 0.320 g*L-1. Calculate the molar mass of eucalyptol..
a)63 g/molb)154 g/molc)0.01 g/mold)10 g/mol
CH301 Vanden Bout/LaBrake Fall 2013
GROUP WORK QUIZ CLICKER QUESTION
Calculate the volume of carbon dioxide, adjusted to 25 ºC and 1.0 atm , that plants need to make 1.00 g of glucose.
6CO2 (g) + 6H2O (l) C6H12O6 (s)+ 6O2 (g)
Unit1Day3-LaBrake Page 12
CH301 Vanden Bout/LaBrake Fall 2013
GROUP WORK QUIZ CLICKER QUESTION
Calculate the volume of carbon dioxide, adjusted to 25 ºC and 1.0 atm , that plants need to make 1.00 g of glucose.
6CO2 (g) + 6H2O (l) C6H12O6 (s)+ 6O2 (g)
CH301 Vanden Bout/LaBrake Fall 2013
What did we learn today?
IDEAL GAS LAW and IDEAL GAS EQUATION
CONCEPT OF NUMBER DENSITY vs MASS DENSITY
DERIVED EQUATION FOR RELATIONSHIP BETWEEN MASS DENSITY AND THE MOLAR MASS OF A GAS
Anything Else? Please Share….
Unit1Day3-LaBrake Page 13
CH301 Vanden Bout/LaBrake Fall 2013
DAY 3 LEARNING OUTCOMES
Perform calculations using the ideal gas equation
Explain the relationship between the number density and the mass density for a given gas
Use the ideal gas law to determine MW of a gas
Apply the concept of the gas laws to gas phase reactionsand perform stoichiometric calculations
Using the gas properties, masses, moles, limiting reagents and percent yields
Unit1Day3-LaBrake Page 14