Be respectful – no electronics please! Announcements Today’s Pre-lecture, and Electronic Homework #2 due tonight at 10:00 pm Pre & Post-lecture Assignments (Lon-Capa) 8:00 am Tuesdays & Thursdays Lab write-up 1 due tomorrow in discussion Textbook homework Assignment 3 due tomorrow in discussion (pg. 16)
Exam Info – Feb. 12th 40% Basic Knowledge & Skills (Pre/Post-lecture questions, book problems) 40-50% Application Questions (Lon-Capa homework questions, lab questions, lecture demonstrations) 10-20% New Problems (Same material, but connected in different ways, or extensions of other problems)
Clicker #1: Discuss When a balloon is placed in a vacuum chamber, what will happen to the balloon after the vacuum pump is turned on? Pop Expand Stay the same size Shrink Completely deflate Be prepared to explain why!
Problem #1 A 10.0 L sample of 0.45 moles of gas is present at 780 torr. What is the temperature of the gas in degrees Celsius?
Problem #1 A 10.0 L sample of 0.45 moles of gas is present at 780 torr. What is the temperature of the gas in degrees Celsius? Size of…? 1) 2) 3)
Problem #1 A 10.0 L sample of 0.45 moles of gas is present at 780 torr. What is the temperature of the gas in degrees Celsius?
Clicker #2 0°C to 40°C is double the temperature of 0°C to 20°C. Does this mean you have twice the amount of kinetic energy in your system? A) Yes. If the temperature doubles then the kinetic energy must also double. They are directly related. B) No. Temperature is related to the heat energy of the gas particles, not the kinetic energy of the gas particles. C) No. Temperature is related to the kinetic energy of the gas particles but must be in relationship to the Kelvin scale.
Problem #2 The vacuum chamber initially contains 2.0 moles of nitrogen gas at a pressure of 1.0 atm. If gas is removed until the new pressure in the container is 0.75 atm, how many moles of gas left the container?
Problem #3 Placing the hot pack into the vacuum chamber increased the temperature from 21C to 23C. If the pressure was initially 1.00 atm, what is the new pressure? (Assume the chamber remained closed and no gas was added or escaped.)
Clicker #3
Problem #4 As a result of his experiences in the vacuum chamber, the marshmallow man has increased in size and is now 120. mL, facing a reduced pressure of 0.80 atm. When the chamber is allowed to return to an internal pressure of 1.0 atm, what will the final size of Mr. Mallow be?
Clicker #4 The temperature of an ideal gas in a flexible container is reduced from 50°C to 25°C. How does the initial volume of the container (V1) compare to the final volume of the container (V2)? V1 and V2 are the equal V1 is twice V2 V2 is twice V1 V1 greater than V2 but less than twice as great V2 is greater than V1 but less than twice as great