Heat of Fusion and Vaporization
Chemistry ⇒ Thermochemistry and Energetics
Heat of Fusion and Vaporization starts at 10 and continues till grade 12.
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See sample questions for grade 10
A 10 g sample of a substance requires 2500 J to vaporize completely. What is its heat of vaporization?
A 100 g sample of water at 100°C is completely vaporized. If the heat of vaporization is 2260 J/g, how much energy is required?
A 15 g sample of a substance at its melting point absorbs 600 J of energy and melts completely. What is its heat of fusion?
A 25 g sample of a liquid requires 56,500 J to boil completely. What is the heat of vaporization?
A student heats 20 g of ice at 0°C with 6680 J of energy. How much ice will remain unmelted? (Heat of fusion = 334 J/g)
Calculate the amount of energy required to melt 50 g of ice at 0°C. (Heat of fusion of ice = 334 J/g)
Describe the difference between heat of fusion and heat of vaporization.
Describe what happens at the molecular level during vaporization.
Describe what happens to the temperature of a substance during a phase change, such as melting or boiling.
Explain why condensation releases energy to the surroundings.
Explain why sweating cools the body in terms of heat of vaporization.
Explain why the heat of vaporization is much higher than the heat of fusion for most substances.
Explain why the temperature does not change during the melting of ice, even though heat is being added.
If 5000 J of energy is supplied to 10 g of ice at 0°C, will all the ice melt? (Heat of fusion = 334 J/g)
If the heat of fusion of a substance is 200 J/g, how much energy is released when 5 g of the substance freezes?
Is the heat of vaporization generally higher or lower than the heat of fusion for the same substance?
The heat of fusion of a substance is 80 cal/g. How much energy is needed to melt 10 g of this substance?
The heat of vaporization of ethanol is 841 J/g. How much energy is needed to vaporize 25 g of ethanol?
What is the heat of fusion?
