When a substance changes state, the number of particles in the substance stays unchanged. So the mass of the substance after the change of state is the same as the mass of the substance before the change of state.
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Card 7
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The particles of a substance in its liquid state are in contact with each other. They move about at random. So a liquid doesn't have its own shape, and it can flow.
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Card 8
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The particles of a substance in its solid, liquid, and gas states have difference amounts of energy. For a given amount of a substance its particles have more energy in gas than liquid state, and have more energy in liquid than solid state.
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Card 9
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For any pure substance undergoing a change of state, its temperature stays the same while the change of state is taking place.
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Card 10
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A beaker of ice below 0' heated slowly until water boils. The temperature of the water 1) increases until reaches 0' and when ice begins to melt 2) stays constant at 0' until all melted 3) increases to 100' where it boils 4) stays at 100' boiling
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Card 11
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Fusion is sometimes used to describe melting because different solids can be joined, or 'fused', together when they melt
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Card 12
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The boiling point of a pure substance is the same temperature at which it condenses.
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Card 13
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P6.4 - Internal energy
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Card 14
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The internal energy of the particles in a substance is the sum of: kinetic energy they have due to their individual motions relative to each other, and potential energy they have due to their individual positions relative to each other.
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Card 15
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When the temperature of a substance increases (or decreases) the total kinetic energy of its particles increases (or decreases).
