Understanding Molar Heat Concepts

What is the molar heat of fusion for water?

• 6.02 KJ/mol

• 40.7 KJ/mol

• 7.61 KJ/mol

• 26.0 KJ/mol

When water freezes, what happens to the thermal energy?

• It is absorbed.

• It is released.

• It remains constant.

• It doubles.

What is the molar heat of vaporization for water?

• 6.02 KJ/mol

• 40.7 KJ/mol

• 7.61 KJ/mol

• 26.0 KJ/mol

During vaporization, what happens to the thermal energy of water?

• It is absorbed.

• It is released.

• It decreases.

• It remains constant.

Which substance has a higher molar heat of vaporization than water?

• Ethanol

• Sodium

• Lead

• Methane

How much energy is needed to melt 125 g of ice at 0°C?

• 41.3 KJ

• 576 KJ

• 25 KJ

• 192 KJ

What is the first step in calculating the energy change for a state change?

• Measure the temperature.

• Convert grams to moles.

• Determine the pressure.

• Calculate the volume.

How much energy is released when 255 g of water vapor condenses at 100°C?

• 192 KJ

• 25 KJ

• 576 KJ

• 41.3 KJ

What is the molar mass of water used in these calculations?

• 16.00 g/mol

• 18.02 g/mol

• 40.7 g/mol

• 2.02 g/mol

How much energy is absorbed when 85 g of water turns into vapor at its boiling point?

• 192 KJ

• 25 KJ

• 576 KJ

• 41.3 KJ