According to first law of thermodynamics, if thermal energy is applied to water placed in a cylinder fitted with a frictionless piston:
Correct answer: D. All of the above
- A. Thermal energy is converted into kinetic energy of water molecules
- B. Pressure of water molecules increases
- C. The piston is pushed up
- D. All of the above
Explanation
This is the correct answer. Let's break down why each individual option is true:Thermal energy is converted into kinetic energy of water molecules. When thermal energy is applied to water, it increases the average kinetic energy of its molecules. This means the water molecules move faster, causing a rise in temperature.Pressure of water molecules increases: As the water molecules move faster, they collide with the walls of the cylinder more frequently and with greater force. This increase in collisions leads to a pressure increase inside the cylinder.The piston is pushed up: Since the pressure within the cylinder increases due to the agitated water molecules, the force applied to the piston also increases. If the piston is frictionless, this force pushes the piston upwards.
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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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