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wec01 wrote:

UTF-8 U+6211 U+662F wrote:How much work is done on a gas that is isothermally compressed to half its original size at a temperature of 40 degrees Réaumur?

Attempt (Click to Show Hidden Text)

- nRTln(V[math]_2[/math]/V[math]_1[/math]) = - n * 8.314 J/(mol*K) * 40 °Ré * ln (1/2) = - n * 8.314 J/(mol*K) * 323 K * ln (1/2) = [b]1860 J/mol[/b]

wec01 wrote:
1) What is this device known as?
2) Who is generally credited with creating it?
3) What is it supposed to measure? What other variable affects the fluid level?

Thermoscope
Galileo
It’s supposed to measure temperature, but pressure affects it too.

mjcox2000 wrote:

wec01 wrote:
1) What is this device known as?
2) Who is generally credited with creating it?
3) What is it supposed to measure? What other variable affects the fluid level?

Answer (Click to Show Hidden Text)

Thermoscope
Galileo
It’s supposed to measure temperature, but pressure affects it too.

mjcox2000 wrote:A hot and cold reservoir are used to convert heat to work in a Carnot cycle. The hot reservoir starts at 400K and has a heat capacity of 40 J/K, and the cold reservoir starts at 100K and has a heat capacity of 20 J/K. The Carnot cycle runs until the reservoirs are in thermal equilibrium.

1. At what temperature do the reservoirs reach equilibrium?
2. How much heat does the hot reservoir lose in the course of this process?
3. How much energy (i.e. work) does the Carnot cycle capture in the course of this process?
4. What is the total efficiency of this process?

1. 300 K
2. 4 kJ
3. 3 kJ
4. 75%

wec01 wrote:

mjcox2000 wrote:A hot and cold reservoir are used to convert heat to work in a Carnot cycle. The hot reservoir starts at 400K and has a heat capacity of 40 J/K, and the cold reservoir starts at 100K and has a heat capacity of 20 J/K. The Carnot cycle runs until the reservoirs are in thermal equilibrium.

1. At what temperature do the reservoirs reach equilibrium?
2. How much heat does the hot reservoir lose in the course of this process?
3. How much energy (i.e. work) does the Carnot cycle capture in the course of this process?
4. What is the total efficiency of this process?

Attempt (Click to Show Hidden Text)

1. 300 K
2. 4 kJ
3. 3 kJ
4. 75%

mjcox2000 wrote:A hot and cold reservoir are used to convert heat to work in a Carnot cycle. The hot reservoir starts at 400K and has a heat capacity of 40 J/K, and the cold reservoir starts at 100K and has a heat capacity of 20 J/K. The Carnot cycle runs until the reservoirs are in thermal equilibrium.

1. At what temperature do the reservoirs reach equilibrium?
2. How much heat does the hot reservoir lose in the course of this process?
3. How much energy (i.e. work) does the Carnot cycle capture in the course of this process?
4. What is the total efficiency of this process?

UTF-8 U+6211 U+662F wrote:

mjcox2000 wrote:A hot and cold reservoir are used to convert heat to work in a Carnot cycle. The hot reservoir starts at 400K and has a heat capacity of 40 J/K, and the cold reservoir starts at 100K and has a heat capacity of 20 J/K. The Carnot cycle runs until the reservoirs are in thermal equilibrium.

1. At what temperature do the reservoirs reach equilibrium?
2. How much heat does the hot reservoir lose in the course of this process?
3. How much energy (i.e. work) does the Carnot cycle capture in the course of this process?
4. What is the total efficiency of this process?

I'm confused how the reservoirs could reach equilibrium? The Carnot cycle assumes that the reservoirs will never change temperature.

The Carnot efficiency equation predicts the instantaneous efficiency. Try integrating.

mjcox2000 wrote:

UTF-8 U+6211 U+662F wrote:

mjcox2000 wrote:A hot and cold reservoir are used to convert heat to work in a Carnot cycle. The hot reservoir starts at 400K and has a heat capacity of 40 J/K, and the cold reservoir starts at 100K and has a heat capacity of 20 J/K. The Carnot cycle runs until the reservoirs are in thermal equilibrium.

1. At what temperature do the reservoirs reach equilibrium?
2. How much heat does the hot reservoir lose in the course of this process?
3. How much energy (i.e. work) does the Carnot cycle capture in the course of this process?
4. What is the total efficiency of this process?

I'm confused how the reservoirs could reach equilibrium? The Carnot cycle assumes that the reservoirs will never change temperature.

The Carnot cycle doesn’t require constant-temperature reservoirs.

Hint (Click to Show Hidden Text)

The Carnot efficiency equation predicts the instantaneous efficiency. Try integrating.

1. 252 K
2. 5920 J
3. 2880 J
4. 48.6 %