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Temperature: States of matter Through Temperature Changes
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Fusion/Melting
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- When the temperature of solids increases, the kinetic energy of particles rises causing them to vibrate more rapidly.
- Heat energy provided overcomes interparticle forces, enabling particles to move freely and transition from a solid to a liquid, this change of state from solid to liquid is called fusion or melting.
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Melting Point:
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- The minimum temperature at which a solid melts to become a liquid at the atmospheric pressure is called its melting point.
- The melting point of a solid is an indication of the strength of the force of attraction between its particles.
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Latent Heat of Fusion:
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- When a solid melts, its temperature remains the same because the heat energy is being used to overcome particle attraction hence showing no change in temperature.
- This is the latent heat of fusion which is defined as the heat energy required to change 1 kg of solid into liquid at its melting point.
- This shows that particles in water at 0℃ (273 K) have more energy as compared to particles in ice at the same temperature.
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Latent Heat of Vaporization:
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- When heat is supplied to water, particles gain energy and eventually reach a point where they can break free, causing the liquid to change into a gas.
- During this transition the temperature change remains hidden, the excess energy is absorbed by the particles and is called as latent heat of vaporization.
 [Sublimation of camphor]
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Sublimation:
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- It involves change directly from solid to gas, this process of change directly, without an intermediate liquid state, from solid to gas is called sublimation.
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Deposition
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- When a substance changes from gas to solid, the process is called deposition.
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