Heat of Fusion Worksheet
Grade 12 Chemistry worksheet exploring the concept of heat of fusion, enthalpy changes during phase transitions, and related calculations.
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Heat of Fusion Worksheet
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Read each question carefully and provide your answer in the space provided. Show all calculations for quantitative problems.
1. What is the definition of the heat of fusion (ΔHfus)?
The energy required to raise the temperature of a substance by 1°C.
The energy released when a substance freezes at its melting point.
The energy required to convert one mole of a solid to a liquid at its melting point.
The energy required to convert one mole of a liquid to a gas at its boiling point.
2. During the melting process of a pure substance, what happens to the temperature?
It increases steadily.
It decreases steadily.
It remains constant.
It fluctuates unpredictably.
3. The heat of fusion is an property, meaning it depends on the amount of substance.
4. The reverse process of melting, where a liquid turns into a solid, is called .
5. The units for heat of fusion are typically or .
6. Explain why a substance's temperature does not change during a phase transition, even though heat is being added or removed.
7. Calculate the amount of heat (in kJ) required to melt 75.0 grams of ice at 0°C. The molar heat of fusion for water is 6.01 kJ/mol. (Molar mass of H2O = 18.02 g/mol)
8. The heat of fusion for a substance is always a positive value.
True
False
9. When a substance freezes, it absorbs energy from its surroundings.
True
False