If a gas is heated at constant pressure, which of the following description(s) will apply?I. The volume increase is proportional to the temperatureII. The kinetic energy of the molecules decreasesIII. The kinetic energy of the molecules increases
Correct answer: D. I and III only
- A. I only
- B. III only
- C. I and II only
- D. I and III only
- E. II and III only
Explanation
At constant pressure Charles's law makes volume proportional to absolute temperature, so statement I holds. Heating also raises the average kinetic energy of the molecules, so statement III holds and statement II states the opposite of what happens.
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Thermal equilibrium and heat explain how temperature and energy transfer are related, while molar specific heats describe the heat required by a gas at constant volume or constant pressure. The first law connects heat supplied, work done and change in internal energy, with sign conventions kept distinct from temperature changes.
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