Part A Identify Energy Exchanges As Primarily Heat Or Work Drag The Items Into The Appropriate Bins. View Available Hint(S) Reset Help Araft Is Inflated Against Pressure Near A Lake Surface. (System: Gas Within The Raft) Lce In A Glass Of Water Melts, Cooling The Water Around It (System: Melting Ice) An Aqueous Chemical Reaction Mixture Is Warmed With An
The Correct Answer and Explanation is :
In thermodynamics, energy exchanges within a system can be categorized primarily as heat or work. Let’s analyze each scenario:
- A raft is inflated against pressure near a lake surface. (System: Gas within the raft)
- Primary Energy Exchange: Work Inflating the raft involves compressing gas against external pressure, which requires work. The gas inside the raft is compressed, increasing its internal energy.
- Ice in a glass of water melts, cooling the water around it. (System: Melting Ice)
- Primary Energy Exchange: Heat The melting of ice absorbs heat from the surrounding water, causing the water to cool. This is an example of heat transfer from the warmer water to the cooler ice, leading to the phase change.
- An aqueous chemical reaction mixture is warmed with a hot plate. (System: Chemical Reaction Mixture)
- Primary Energy Exchange: Heat Heating the reaction mixture with a hot plate involves transferring heat to the system, increasing the kinetic energy of the molecules and potentially affecting the reaction rate.
Explanation:
- Work involves energy transfer due to a force acting over a distance, such as compressing gas or moving an object. In the first scenario, inflating the raft requires work to compress the gas inside against external pressure.
- Heat is energy transfer due to a temperature difference between the system and its surroundings. In the second scenario, the melting ice absorbs heat from the surrounding water, leading to a temperature change in the water.
- In the third scenario, heating the reaction mixture with a hot plate transfers heat to the system, affecting the reaction’s progress.
Understanding these distinctions is crucial in thermodynamics, as they determine how energy is transferred and transformed within systems.