Internal energy after evaporation?

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SUMMARY

The discussion centers on calculating the change in internal energy after vaporizing 2 grams of water, requiring 1664 calories for vaporization. The conversion of calories to joules is correctly performed, resulting in 6965.504 J. However, the user incorrectly attempts to divide this value by the mass of the water, indicating a misunderstanding of the relationship between heat, mass, and internal energy in this context. The problem is identified as under-specified, lacking necessary details for a complete solution.

PREREQUISITES
  • Understanding of the first law of thermodynamics
  • Knowledge of heat transfer and phase changes
  • Familiarity with unit conversions, specifically between calories and joules
  • Basic principles of internal energy in thermodynamics
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  • Study the first law of thermodynamics and its applications
  • Learn about phase changes and the energy involved in vaporization
  • Practice unit conversions between different energy units, focusing on calories and joules
  • Explore detailed examples of internal energy calculations in thermodynamic systems
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Students studying thermodynamics, physics educators, and anyone seeking to understand energy changes during phase transitions in substances.

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Homework Statement



Two grams of water are sealed in a rigid con-
tainer; then the water is vaporized by heating.
1664 cal of heat is needed for vaporization.
What is the change in internal energy of the
water?
Answer in units of J.

Homework Equations



1 kcal= 4,186 J

The Attempt at a Solution



seems simple because there are only 2 given variables, so I don't know what I am doing wrong. Here is what I tried...
I first changed 1664 cal to 1.664 kcal then times that by 4186 J to get 6965.504 J then I divided that by .002 kg (change 2 g to .002 kg) but that answer was incorrect.

Any help to point me in the right direction would be greatly appreicated :)
 
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This problem statement is under-specified. There is missing information.
 

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