Gas Laws - Theory
A sealed, rigid container of gas is heated. Which variables remain constant?
volume and number of moles
A gas sample occupies 2.0 L at 1.0 atm. If the volume is compressed to 0.50 L at constant temperature, what is the new pressure?
4.0 atm
In thermodynamics, what does it mean when work (w) is positive under the chemistry sign convention?
work is being done on the system by the surroundings
What is the difference between an endothermic and an exothermic process in terms of heat transfer between the system and its surroundings?
Endothermic processes absorb heat from the surroundings (q>0); exothermic processes release heat to the surroundings (q<0)
In “The Nightmare Before Christmas,” what’s the name of the Pumpkin King?
Jack Skellington
assuming the volume of a gas stays constant, if temperature is increased, what would you expect to happen to pressure?
pressure would increase
A sample of gas occupies 405 mL at 298 K. If pressure remains constant, what volume will it occupy if heated to 467 K?
635 mL
A gas expands from 2.00 L to 5.00 L against a constant external pressure of 1.50 atm. Calculate the work done in Joules (1 L*atm = 101.325 J)
-456 J
A 50.0 g sample of water is heated from 20.0°C to 35.0°C. Given that the specific heat of water is 4.184 J/(g·°C), calculate the heat absorbed by the water in joules.
3.14 x 103 J
If someone has Samhainophobia, what are they afraid of?
Halloween
Why does a balloon expand when heated, assuming the external pressure remains constant?
The particles inside the balloon move faster, causing the balloon to expand
A container holds 4.0 mol of He and 6.0 mol of Ne at a total pressure of 15.0 atm. What is the partial pressure of helium (He)?
6.0 atm
What is the difference between a system doing work and work being done on a system? (as it relates to energy transfer)
a system doing work transfers energy to its surroundings, while work done on a system transfers energy from its surroundings into the system.
A hot metal sample is placed in cooler water inside an insulated container. Which substance loses heat, which gains heat, and what is the relationship between the heat transferred by the two substances?
The metal loses heat, and the water gains heat. In an insulated system, qhot=-qcold
What were the first-ever fun-size candy bars?
Snickers and Milky Way
A gas is transferred into a container with twice the original volume. Its absolute temperature is also doubled, and the number of moles remains constant. How does its pressure compare with its original pressure?
It's the same
Calculate the pressure in atmospheres exerted by 3.46 moles of CO2 in a 4.25-L flask at 502.15 K (229 °C) using R = 0.08206 L*atm/mol*K.
33.5 atm
A gas expands into a vacuum. Why is no work performed, even though the gas changes volume?
because there is no external pressure opposing the expansion, so no energy is transferred through work
A 25.0 g sample of aluminum is heated from 22.0°C to 75.0°C. Given that aluminum has a specific heat of 0.900 J/(g·°C), calculate the heat absorbed in kilojoules.
1.19 kJ
What candy was originally called “Chicken Feed”?
Candy corn
Two sealed, rigid containers have the same volume and contain the same number of gas particles. Container A contains helium, while Container B contains oxygen. Both containers are at the same temperature. If the gases are ideal, how will the pressure be different in the two containers?
the pressure will be equal
A 3.00 L container of gas at 250 K and 1.50 atm is expanded to 5.00 L while its temperature increases to 400 K. Assuming the amount of gas remains constant, calculate the final pressure.
1.44 atm
Two gases undergo the same increase in volume. Gas A expands against a constant external pressure of 1.0 atm, while Gas B expands against 3.0 atm. Which gas has a greater magnitude of work, and why?
Gas B, because it expands against a greater external pressure over the same volume change
A reaction occurs in a constant-volume bomb calorimeter. The calorimeter has a heat capacity of 2500 J/°C, and its temperature increases by 3.20°C.
a. Calculate the heat absorbed by the calorimeter
b. Is the reaction endothermic or exothermic?
a. 8.00 kJ
b. exothermic
What U.S. city hosts the world’s largest Halloween parade?
New York City