Enthalpy and Phase Changes Answers

Copper has a Hfus = 13.0 kJ/mol. What mass of copper releases 112.4 kJ of heat as it freezes?Use .

An engineer wants to determine an efficient method for condensing large amounts of steam into liquid water. Which constant should she use?

The molar heat of fusion for water is 6.01 kJ/mol. How much energy must be added to a 75.0-g block of ice at 0°C to change it to 75.0 g of liquid water at 0°C?Use .

A chemist wants to calculate the amount of heat that is absorbed by a sample of copper as it is melted. Which constant should she use?

The graph below illustrates a change in energy during a phase change.Which explanation correctly describes the phase change in the graph?

Which term is used to describe the amount of heat that is required to melt 1 mol of a substance?

What scientific tool would be the most helpful when measuring the temperature of a substance that is undergoing a phase change?

NaCl has a Hfus = 30.2 kJ/mol. What is the mass of a sample of NaCl that needs 732.6 kJ of heat to melt completely?Use .

A sample of substance X that has a mass of 326.0 g releases 4325.8 cal when it freezes at its freezing point. If substance X has a molar mass of 58.45 g/mol, what is the molar heat of fusion for substance X?Use .

Consider the graph below.Which phase change is most likely taking place in this graph?