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MHT CET202521 Apr 2025Evening ShiftChemistryThermodynamics (C)Actual

Calculate the change in internal energy of the system if 25 kJ of work done by the system and it absorbs 10 kJ of heat.

Options

  1. A-10 ~kJ
  2. B-35 ~kJ
  3. C-15 ~kJ
  4. D-25 ~kJ

Correct answer

C. -15 ~kJ

Step-by-step solution

The First Law of Thermodynamics provides the relationship between internal energy, heat, and work: U = q + w . Applying the standard sign convention, work done by the system is negative ( w = -25 , kJ ), while heat absorbed by the system is positive ( q = 10 , kJ ). Substituting these values yields: U = 10 + (-25) = -15 , kJ The change in internal energy is therefore -15 , kJ . Final Answer: C

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