Solving the Hardest Thermal Process Question: Find W/Q Ratio

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SUMMARY

The discussion centers on calculating the work-to-heat ratio (W/Q) in a thermodynamic process involving water heated in an open pan at 1 atm pressure. The formula for work done by water is established as W = P(Vf - Vi), where Vf and Vi represent the final and initial volumes, respectively. The heat absorbed by the water is debated, with the initial suggestion of Q = cm delta T being questioned. The conversion of calories to Joules is also highlighted as a critical step in the calculation.

PREREQUISITES
  • Understanding of thermodynamic principles, specifically the first law of thermodynamics.
  • Familiarity with the concepts of work (W) and heat (Q) in thermodynamic systems.
  • Knowledge of specific heat capacity (c) and its application in heat transfer calculations.
  • Ability to convert units, particularly from calories to Joules.
NEXT STEPS
  • Research the first law of thermodynamics and its applications in open systems.
  • Learn about the specific heat capacity of water and its implications in thermal processes.
  • Study the conversion methods between calories and Joules for accurate energy calculations.
  • Explore advanced thermodynamic equations involving work and heat in various states of matter.
USEFUL FOR

Students and professionals in thermodynamics, mechanical engineers, and anyone involved in thermal process analysis will benefit from this discussion.

Dooh
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This question is considered one of the hardest in this chapter regarding thermodynamics. I spent countless time trying to figure it out but i was never close to the answer. The question is:

Water is heated in an open pan where the air pressure is 1atm. WAter remains a liquid but expanded by a small amount when it was heated. FIND THE RATIO OF WORK DONE BY WATER TO THE HEAD ABSOBED BY THE WATER.

So that means:

W / Q

where W = P(Vf - Vi)
but what's Q? I tried Q = cm delta T but i was wrong. if anyone can help me i'd appreciate it thanks.
 
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Q=cm delta T seems right. Did you convert calories to Joules?
 

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