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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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.
A 10.0 g sample of a substance at its boiling point absorbs 3.60 kJ of energy and vaporizes completely. What is the molar heat of vaporization if the molar mass of the substance is 20.0 g/mol?
A 200 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. Show all steps in your calculation.
A chemist is studying a new compound. She finds that 2.5 kJ of energy is required to melt 50 g of the compound at its melting point. Calculate the molar heat of fusion if the molar mass of the compound is 100 g/mol.
A sample of a substance is heated from -10°C to 120°C. The sample undergoes melting at 0°C and boiling at 100°C. List all the energy changes that must be considered to calculate the total energy required, and briefly describe each.
Which of the following best defines the heat of fusion? (1) The energy required to change a solid to a liquid at its melting point (2) The energy required to change a liquid to a gas at its boiling point (3) The energy released when a gas condenses to a liquid (4) The energy required to raise the temperature of 1 g of a substance by 1°C
Which of the following best describes the energy change during freezing? (1) Energy is absorbed (2) Energy is released (3) No energy change (4) Energy is converted to mass
Which of the following best describes the heat of vaporization? (1) The energy required to convert a solid to a liquid (2) The energy required to convert a liquid to a gas (3) The energy released when a gas condenses to a liquid (4) The energy required to raise the temperature of a solid
Which of the following best explains why the temperature remains constant during a phase change? (1) The system is losing energy (2) The energy is used to break intermolecular bonds (3) The energy is used to increase kinetic energy (4) The system is isolated
Fill in the blank: The energy required to change 1 mole of a liquid to a gas at constant temperature is called the __________ heat of vaporization.
Fill in the blank: The heat of fusion is the amount of energy required to change a solid to a liquid at its __________ point.
Fill in the blank: The heat of vaporization is the amount of energy required to convert 1 __________ of a liquid to a gas at its boiling point.
Fill in the blank: The heat required to change 1 mole of a solid to a liquid at constant temperature is called the __________ heat of fusion.
During the melting of ice at 0°C, the temperature of the system remains constant until all the ice has melted. True or False?
True or False: The heat of fusion is an exothermic process.
True or False: The heat of fusion is used to calculate the energy required to freeze a liquid.
True or False: The heat of vaporization can be used to calculate the energy released when a gas condenses to a liquid.
