Questions and Answers
What is the process called when a solid changes to a liquid?
What is the process called when a liquid changes to a solid?
What is the term for the process when a liquid converts to a gas?
Vaporization
What is the term for the process when a gas converts to a liquid?
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What is the process called when a gas changes directly to a solid?
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What is the term for the process when a solid converts directly to a gas?
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During a phase change, the temperature of a substance changes.
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Energy is either ___________ or ____________ during a phase change.
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What is an endothermic change?
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What is the heat of fusion?
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What occurs during an exothermic change?
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What is the heat of vaporization?
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What is evaporation?
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Study Notes
Phase Changes Overview
- Melting: Transition from solid to liquid through an endothermic reaction, absorbing heat.
- Freezing: Conversion from liquid to solid in an exothermic reaction, releasing heat previously absorbed during melting.
Key Phase Changes
- Vaporization: Endothermic process of changing a liquid to gas as it absorbs heat.
- Condensation: Exothermic phase change transitioning gas to liquid, releasing energy.
- Deposition: An exothermic direct change from gas to solid, releasing heat energy (e.g., frost formation).
- Sublimation: Endothermic change where solid transforms directly to gas, absorbing energy (e.g., dry ice).
Temperature Dynamics
- During phase changes, temperature remains constant despite changes in state.
- Energy during a phase change is either absorbed or released by the system.
Endothermic and Exothermic Changes
- Endothermic Changes: Absorb energy, such as melting, vaporization, and sublimation.
- Exothermic Changes: Release energy, including freezing, condensation, and deposition.
Energy Quantities
- Heat of Fusion: Energy required to change a substance between solid and liquid states; equal energy is absorbed for melting and released for freezing (334 Joules for 1 gram of water).
- Heat of Vaporization: Energy necessary to convert a liquid to gas or vice versa; 2261 Joules are gained by 1 gram of water when vaporizing, and varies by substance.
Additional Concepts
- Evaporation: Phase change where a liquid transitions to gas at temperatures below its boiling point.
- Sublimation and Deposition: Distinct processes for solids transitioning to gas or gas to solid, respectively.
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Description
Test your knowledge on the various phase changes including melting, freezing, vaporization, condensation, deposition, and sublimation. Understand the concepts of endothermic and exothermic reactions and the dynamics of temperature changes during these processes.