A chemist heated a balloon by supplying 600 J of heat. The balloon expandsdoing 200 J of work against the atmospheric pressure. The change in internalenergy of
Correct answer: A. -800 J
- A. -800 J
- B. -400 J
- C. O J
- D. +400J
Explanation
The change in internal energy (AU) of a system is given by the difference between the heat added to the system (q) and the work done by the system (w):AU q-wGiven: Heat added to the balloon (q) = 600 J (positive because heat is added to the system) Work done by the balloon (w) = 200 J (negative because work is done by the system)Substitute the given values into the equation:AU-6001-(-200J)A-6001+200 J800 jTherefore, the correct answer is:800j
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About Thermochemistry and Energetics of Chemical Reactions
Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
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