When you heat up most substances it gives them more Kinetic energy and the substance becomes less arranged in an ordered state, further apart and move faster. therefore the answer is the first: They gain a higher average kinetic energy
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Answer:
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Explanation:
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Gain enough kinetic energy to get past each other. Ad you heat up a substance, the temperature increases as does the kinetic energy of the particles. At a point the temperature of the substance will stop increasing. The energy is now being used to increase the potential and move the particles further apart.