To determine whether each process is endothermic or exothermic, we need to consider the energy transfer and changes involved in each process:
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A fire (the system is the fire):
- This process is exothermic. A fire releases energy in the form of heat and light as it burns fuel, indicating that energy is being released to the surroundings.
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A car engine (the system is the engine):
- This process is also exothermic. A car engine converts chemical energy from fuel into mechanical energy, producing heat as a byproduct. The combustion of fuel releases energy, which raises the temperature of the engine and its components.
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A melting ice sculpture (the ice is the system):
- This process is endothermic. Melting involves absorbing heat from the surroundings to change the solid (ice) to a liquid (water). The ice takes in energy to overcome the forces holding its molecules in a solid state.
Here's a summary:
- Endothermic: Melting ice sculpture
- Exothermic: Fire, Car engine