Phase Changes and Heating Curves

The video tutorial by Mr. Millings explains the concepts of heating and cooling curves using water and ethanol as examples. It covers how substances change phases at specific temperatures, such as melting and boiling points, and describes the energy involved in these phase changes, known as the heat of fusion and heat of vaporization. The tutorial also highlights the plateau regions on the curves where temperature remains constant during phase transitions.

What does a plateau in a heating curve indicate?

• A decrease in temperature

• An increase in temperature

• A change in the substance's color

• A constant temperature during a phase change

At what temperature does ice begin to melt on the Celsius scale?

• 50°C

• 0°C

• 20°C

• 100°C

What is the heat of fusion?

• The energy required to increase the temperature of a gas

• The energy required to convert a liquid into a gas

• The energy required to decrease the temperature of a liquid

• The energy required to convert a solid into a liquid

What happens at the boiling point of water?

• Water changes color

• Water remains as liquid

• Water turns into vapor

• Water turns into ice

What is the condensation point of water on the Celsius scale?

• 0°C

• 50°C

• 100°C

• 150°C

During the cooling curve of water, what occurs at the freezing point?

• Water turns into vapor

• Water changes color

• Water turns into ice

• Water remains as liquid

At what temperature does ethanol begin to melt?

• 0°C

• 78°C

• 100°C

• 115°C

What is the boiling point of ethanol?

• 78°C

• 115°C

• 0°C

• 100°C

Between which points does the heat of fusion occur for ethanol?

• A and B

• D and E

• B and C

• C and D

What phase change occurs between points E and F in the heating curve of ethanol?

• Liquid to solid

• Liquid to gas

• Solid to liquid

• Gas to liquid