Enthalpy Changes in Phase Transitions

The video tutorial explains how to calculate the enthalpy change when converting one mole of ice at -50°C to water at 25°C under 1 atm pressure. It covers the use of specific heats for ice, water, and steam, as well as the enthalpy of fusion and vaporization. The instructor draws a heating curve to illustrate the process and calculates the enthalpy changes for warming ice, melting ice, and warming liquid water. The final step involves summing these enthalpy changes to find the total enthalpy change for the entire process.

What is the initial temperature of ice in the enthalpy change problem?

• 25°C

• 0°C

• -50°C

• -100°C

What is the final temperature of water in the enthalpy change problem?

• 100°C

• 50°C

• 25°C

• 0°C

In a heating curve, what does the horizontal line at 0°C represent?

• Condensation of steam

• Boiling of water

• Melting of ice

• Cooling of ice

Which specific heat capacity is used to calculate the enthalpy change for warming ice?

• Specific heat of steam

• Specific heat of water

• Specific heat of air

• Specific heat of ice

What is the enthalpy of fusion used for in this problem?

• Boiling water

• Melting ice

• Condensing steam

• Warming ice

How many kilojoules are required to melt one mole of ice?

• 4.18 kJ

• 1.883 kJ

• 6.01 kJ

• 9.78 kJ

Which specific heat capacity is used to calculate the enthalpy change for warming water?

• Specific heat of air

• Specific heat of ice

• Specific heat of water

• Specific heat of steam

What is the total enthalpy change for converting ice at -50°C to water at 25°C?

• 7.78 kJ

• 1.883 kJ

• 9.78 kJ

• 6.01 kJ

What is the change in temperature when warming water from 0°C to 25°C?

• 25°C

• 75°C

• 50°C

• 15°C

What is the specific heat capacity of water used in the calculation?

• 9.78 J/g·K

• 6.01 J/g·K

• 4.18 J/g·K

• 2.09 J/g·K