High School Physics Competition: Change in Entropy

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SUMMARY

The change in entropy for a system receiving 1.25 x 103 J of heat at a constant temperature of 75.0°C (348 K) is calculated using the formula ΔS = Q/T, resulting in a value of 3.59 J/K. The correct answer choice is c) + 3.59 J/K, as the hashtag in option d) indicates a negative value, which is incorrect in this context. The discussion clarifies that the hashtag signifies "negative," leading to confusion among participants.

PREREQUISITES
  • Understanding of thermodynamics principles, specifically entropy.
  • Familiarity with the formula ΔS = Q/T for calculating entropy changes.
  • Knowledge of temperature conversion from Celsius to Kelvin.
  • Basic problem-solving skills in physics competitions.
NEXT STEPS
  • Study the laws of thermodynamics, focusing on entropy and its implications.
  • Learn about the significance of temperature scales, particularly Kelvin and Celsius conversions.
  • Explore common notations in physics problems, including symbols and abbreviations.
  • Practice additional entropy calculation problems to reinforce understanding.
USEFUL FOR

Students participating in physics competitions, educators teaching thermodynamics, and anyone interested in understanding entropy and its calculations in thermodynamic systems.

ReneG
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During a physics competition, I came across this question.
What is the change in entropy of the system when 1.25 " 103 J of heat is added to the system that is maintained at a constant 75.0 C?

My work was
\begin{align*}\Delta S &= \frac{Q}{T} \\ \Delta S &= \frac{1.25 \times 10^3 \, \mathrm{J}}{348 \, \mathrm{K}} \\ \Delta S &= 3.59 \,\,\mathrm{\left( J/K\right )} \end{align*}

but I was stuck in between two answer choices

c) + 3.59 J/K
d) # 3.59 J/K

I had no idea what the hashtag meant, so I skipped it. Can someone clear this up for me?
 
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Honestly I have no idea, but certainly the change in entropy is positive, so answer c) is correct. Maybe it's a misprint?
 
I guess what dipole said it's right 'cause it sometimes happens
 
Last edited:
For anyone who was wondering, the hashtag just meant "negative". Thank you dipole.
 

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