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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A 10 g sample of ice at 0°C is melted and then heated to 100°C. How much energy is required? (Heat of fusion = 334 J/g, specific heat of water = 4.18 J/g°C)
A 100 g sample of water at 0°C is to be converted to steam at 100°C. Calculate the total energy required, given: heat of fusion = 334 J/g, specific heat of water = 4.18 J/g°C, heat of vaporization = 2260 J/g.
A 20 g sample of a substance requires 500 J to melt completely at its melting point. What is the heat of fusion of the substance?
A 25 g sample of a substance at its melting point absorbs 1000 J of energy and melts completely. What is the heat of fusion?
A 30 g sample of a substance at its boiling point absorbs 6000 J of energy and completely vaporizes. What is the heat of vaporization?
A 5 g sample of a substance requires 1500 J to vaporize at its boiling point. What is the heat of vaporization?
A 50 g sample of a liquid at its boiling point requires 11,300 J to vaporize completely. What is the heat of vaporization?
Calculate the mass of water (in grams) that can be vaporized by 10,000 J of energy at 100°C. (Heat of vaporization of water = 2260 J/g)
Describe how the heat of vaporization is measured experimentally.
Describe the difference between heat of fusion and heat of vaporization.
Describe what happens at the molecular level during the vaporization of a liquid.
Explain the significance of the heat of fusion in the context of climate and the melting of polar ice.
Explain why substances with strong intermolecular forces have higher heats of fusion and vaporization.
Explain why temperature does not change during the melting or boiling of a pure substance, even though heat is being added.
Explain why the heat of vaporization is generally much higher than the heat of fusion for most substances.
If 5000 J of energy is released when a substance freezes, what is the heat of fusion if the mass of the substance is 20 g?
The heat of fusion of a substance is 80 cal/g. How much energy is needed to melt 25 g of this substance at its melting point?
The heat of fusion of ice is 334 J/g. Calculate the amount of energy required to melt 50 g of ice at 0°C.
The heat of fusion of lead is 24.5 J/g. How much energy is needed to melt 10 g of lead at its melting point?
The heat of vaporization of ethanol is 841 J/g. How much energy is required to vaporize 15 g of ethanol at its boiling point?
