.Calculating Heat Released from Gas Expansion at Constant Temperature

In summary, the formula for calculating heat released from gas expansion at constant temperature is Q = nCpΔT, where Q is the heat released, n is the number of moles of gas, Cp is the heat capacity at constant pressure, and ΔT is the change in temperature. The number of moles of gas can be determined by dividing the mass of the gas by its molar mass, or by using the ideal gas law equation, n = PV/RT. Constant temperature is important in this calculation because it ensures that the internal energy of the gas remains the same throughout the expansion process. Heat capacity affects the calculation by requiring more heat energy for a larger change in temperature, resulting in a smaller value for Q. This
  • #1
pkossak
52
0
An ideal gas at pressure, volume, and temp, Po, Vo, and To, respectively, is heated to point A, allowed to expand to point B also at A's temperature 2To, and then returned to the original condition. The internal energy increases by 3PoVo/2 going from point B to point To. How much heat left the gas from point B to point To?

a. 0 b. PoVo/2 c. 3PoVo/2 d. 5PoVo/2

http://www.msu.edu/~kossakze/pvt.gif

Not sure about this one. Any suggestions? Thanks
 
Physics news on Phys.org
  • #2
Can't understand how internal energy increases if the temp. changes from 2T0 to T0??
 
  • #3


The correct answer is a. 0. This is because the process described is an isothermal expansion, meaning the temperature remains constant throughout. In an isothermal process, the change in internal energy is equal to 0, so no heat would be released or absorbed by the gas. The internal energy only increases when the temperature changes, which does not occur in this scenario. Therefore, the correct answer is 0.
 

FAQ: .Calculating Heat Released from Gas Expansion at Constant Temperature

What is the formula for calculating heat released from gas expansion at constant temperature?

The formula is Q = nCpΔT, where Q is the heat released, n is the number of moles of gas, Cp is the heat capacity at constant pressure, and ΔT is the change in temperature.

How do you determine the number of moles of gas in a system?

You can determine the number of moles of gas by dividing the mass of the gas by its molar mass, or by using the ideal gas law equation, n = PV/RT, where P is the pressure, V is the volume, R is the gas constant, and T is the temperature.

What is the significance of constant temperature in this calculation?

Constant temperature is important because it ensures that the internal energy of the gas remains the same throughout the expansion process. This means that all of the work done by the expanding gas is converted into heat, and there is no change in the internal energy of the system.

How does heat capacity affect the calculation of heat released from gas expansion?

Heat capacity is a measure of how much heat energy is required to raise the temperature of a substance by a certain amount. In this calculation, a higher heat capacity means that more heat energy is required to produce a certain change in temperature, resulting in a smaller value for Q.

Can this formula be used for both ideal and non-ideal gases?

Yes, this formula can be used for both ideal and non-ideal gases. However, for non-ideal gases, the heat capacity will vary with temperature and pressure, so the calculation may not be as accurate as it is for ideal gases.

Similar threads

Why is temperature constant after gas has expanded?
Replies
33
Views
2K
Calculate ideal-gas temperature of a material
Replies
2
Views
1K
Gas temperature in a constant volume
Replies
8
Views
1K
What Happens When Gas Expands at Constant Pressure?
Replies
12
Views
6K
Minimum heat removed from gas to restore its state
Replies
5
Views
2K
Calculating Work Done by Gas at Constant Pressure
Replies
2
Views
2K
Open Gas Turbine - calculate T2, T3, T4, efficiency
Replies
1
Views
1K
Internal Energy of an Ideal Gas
Replies
4
Views
2K
Thermodynamics: gas expansion formula or approximation error?
Replies
2
Views
986
Efficiency of Stirling Cycle - Is it the same as the Carnot Engine?
Replies
14
Views
527

Hot Threads

Recent Insights

Back
Top