Phase Change Chemistry Example 1

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Example 1

easy
Name the six phase changes and indicate whether each absorbs or releases energy.

Solution

  1. 1
    Group the phase changes into those that absorb energy and those that release it.
  2. 2
    Endothermic changes absorb energy: melting (solid→liquid), vaporization (liquid→gas), and sublimation (solid→gas).
  3. 3
    Exothermic changes release energy: freezing (liquid→solid), condensation (gas→liquid), and deposition (gas→solid).

Answer

Endothermic: melt, vaporize, sublime. Exothermic: freeze, condense, deposit.\text{Endothermic: melt, vaporize, sublime. Exothermic: freeze, condense, deposit.}
Phase changes involve energy transfer but not temperature change (at the phase transition point). The energy goes into breaking or forming intermolecular bonds rather than increasing kinetic energy.

About Phase Change

A physical transition from one state of matter to another caused by adding or removing thermal energy, during which the temperature remains constant as energy.

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