## Thermodynamics B/C

Test your knowledge of various Science Olympiad events.
Justin72835
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### Re: Thermodynamics B/C

You have a metal pot with heat capacity 540 J/K at a temperature of 114 °C. You then add 350 mL of water at 23 °C into the pot.

a. Is there any steam produced? (yes or no)

b. If yes, then what is the final temperature of the steam? If no, then what is the equilibrium temperature between the water and the pot?
Assuming the whole pot of water has to get to 100 degrees before any steam is produced:
Energy to heat water + energy to boil water + energy to heat steam = energy lost from metal pot.
$4.2 \frac{J}{g*K} * 350 mL * 1 \frac{g}{mL} * 77 K + 2230 J/g * 350 mL * 1 \frac{g}{mL} + 2.0 \frac{J}{g*K} * 350 mL * 1 \frac{g}{mL} * (T - 100 \degree C) = 540 \frac{J}{K} * (114 \degree C - T)$
=> T = -615 degrees Celsius, which is clearly impossible.

$4.2 \frac{J}{g*K} * 350 mL * 1 \frac{g}{mL} * (T - 23 \degree C) = 540 \frac{J}{K} * (114 \degree C - T)$
=> T = 47 degrees Celsius

a) No
b) 47 degrees Celsius
Nice job; your turn!
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."

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UTF-8 U+6211 U+662F
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### Re: Thermodynamics B/C

Explain why we can make assumptions in the derivation of the ideal gas law, PV = nRT, such as "The number of molecules moving in each axis (x, y, and z) is equal".

Justin72835
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### Re: Thermodynamics B/C

Explain why we can make assumptions in the derivation of the ideal gas law, PV = nRT, such as "The number of molecules moving in each axis (x, y, and z) is equal".
Answer
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."

University of Texas at Austin '23
Seven Lakes High School '19

UTF-8 U+6211 U+662F
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Posts: 1491
Joined: January 18th, 2015, 7:42 am
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### Re: Thermodynamics B/C

Explain why we can make assumptions in the derivation of the ideal gas law, PV = nRT, such as "The number of molecules moving in each axis (x, y, and z) is equal".
Answer
Yep, your turn

Justin72835
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### Re: Thermodynamics B/C

Two gases occupy two containers, A and B. The gas in A, of volume 0.14 cubic meters, exerts a pressure of 1.18 MPa. The gas in B, of volume 0.21 cubic meters, exerts a pressure of 0.82 MPa. The containers are united by a tube of negligible volume and the gases are allowed to intermingle. What is the final pressure in the container if the temperature remains constant?
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."

University of Texas at Austin '23
Seven Lakes High School '19

MattChina
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### Re: Thermodynamics B/C

Two gases occupy two containers, A and B. The gas in A, of volume 0.14 cubic meters, exerts a pressure of 1.18 MPa. The gas in B, of volume 0.21 cubic meters, exerts a pressure of 0.82 MPa. The containers are united by a tube of negligible volume and the gases are allowed to intermingle. What is the final pressure in the container if the temperature remains constant?
answer
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Justin72835
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Posts: 175
Joined: June 25th, 2017, 7:06 am
Division: Grad
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### Re: Thermodynamics B/C

Two gases occupy two containers, A and B. The gas in A, of volume 0.14 cubic meters, exerts a pressure of 1.18 MPa. The gas in B, of volume 0.21 cubic meters, exerts a pressure of 0.82 MPa. The containers are united by a tube of negligible volume and the gases are allowed to intermingle. What is the final pressure in the container if the temperature remains constant?
answer
Not quite. How did you get your answer?

EDIT: This answer is actually correct.
Last edited by Justin72835 on April 4th, 2018, 7:18 pm, edited 1 time in total.
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."

University of Texas at Austin '23
Seven Lakes High School '19

UTF-8 U+6211 U+662F
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Posts: 1491
Joined: January 18th, 2015, 7:42 am
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### Re: Thermodynamics B/C

Two gases occupy two containers, A and B. The gas in A, of volume 0.14 cubic meters, exerts a pressure of 1.18 MPa. The gas in B, of volume 0.21 cubic meters, exerts a pressure of 0.82 MPa. The containers are united by a tube of negligible volume and the gases are allowed to intermingle. What is the final pressure in the container if the temperature remains constant?
answer
Not quite. How did you get your answer?
I got the same answer :/

MattChina
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### Re: Thermodynamics B/C

Two gases occupy two containers, A and B. The gas in A, of volume 0.14 cubic meters, exerts a pressure of 1.18 MPa. The gas in B, of volume 0.21 cubic meters, exerts a pressure of 0.82 MPa. The containers are united by a tube of negligible volume and the gases are allowed to intermingle. What is the final pressure in the container if the temperature remains constant?
answer
Not quite. How did you get your answer?

(P1V1/Vf)+(P2V2/Vf)
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Justin72835
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### Re: Thermodynamics B/C

Nevermind, both of you (UTF-8 U+6211 U+662F and MattChina) are right. I messed up my calculations beforehand

Anyways, great job to both of you and sorry for the confusion! I think it's MattChina's turn now.
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."

University of Texas at Austin '23
Seven Lakes High School '19

MattChina
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### Re: Thermodynamics B/C

Lets do this. What is the best way to increase the efficiency of a carnot engine?
2019 events: Water Quality, Battery Buggy, Elastic Launch Glider, Density Lab, Circuit Lab, Thermodynamics
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Justin72835
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Joined: June 25th, 2017, 7:06 am
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### Re: Thermodynamics B/C

Lets do this. What is the best way to increase the efficiency of a carnot engine?
Answer
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."

University of Texas at Austin '23
Seven Lakes High School '19

UTF-8 U+6211 U+662F
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Joined: January 18th, 2015, 7:42 am
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### Re: Thermodynamics B/C

Lets do this. What is the best way to increase the efficiency of a carnot engine?
Answer
(i.e.)

Justin72835
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Posts: 175
Joined: June 25th, 2017, 7:06 am
Division: Grad
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### Re: Thermodynamics B/C

Lets do this. What is the best way to increase the efficiency of a carnot engine?
Answer
(i.e.)
Oh, I completely misread that question.
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."

University of Texas at Austin '23
Seven Lakes High School '19

MattChina
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Posts: 224
Joined: February 12th, 2017, 8:06 am
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### Re: Thermodynamics B/C

Lets do this. What is the best way to increase the efficiency of a carnot engine?
Answer
(i.e.)
correct. your turn
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