WorksheetsHeating Cooling Curves
Total questions: 15
Worksheet time: 15mins
The following image shows the temperature change of a substance as thermal energy is released over time. Select all regions where the phase is changing
AB
BC
CD
DE
E to the end
This curve represents a _____ curve because the temperature is ______ (a) (b)
heating
increasing
cooling
decreasing
Select 2 terms that represent PHASE CHANGES that can happen if a sample of matter absorbs thermal energy
melting
gas
freezing
liquid
boiling
On a heating or cooling curve, the substance is a single state of matter (solid, liquid, or gas) when the line is
sloped (going up or down at an angle)
horizontal (flat)
The following image shows the temperature change of a substance as thermal energy is released over time.
At BC, the temperature is ________ °C and the phase change is called ___________
(a) (b)
150
100
freezing
condensation
boiling
Region QR represents a substance in the liquid phase. What does region RS represent?
melting
boiling
solid
gas
Region QR represents a substance in the liquid phase. What does region ST represent?
melting
boiling
solid
gas
Region QR represents a substance in the liquid phase. Is this substance possibly water? How do you know?
(a) (b)
yes
no
This substance boils at 100 degrees C
This substance freezes at 40 degrees C
This substance boils at 110 degrees C
If Region AB is a gas, identify BC and C to the end.
condensation
liquid
boiling
freezing
solid
Which phase change occurs at the flat portions of a heating curve?
Melting and boiling
Freezing and condensation
Sublimation and deposition
Evaporation and freezing
What does a horizontal line on a cooling curve represent?
A change in temperature
A phase change
A chemical reaction
An increase in kinetic energy
During which phase change does a substance absorb energy without a change in temperature?
Melting
Freezing
Condensation
Deposition
In a heating curve, what does the slope of the line indicate?
The substance is undergoing a phase change
The substance is in a single state of matter
The substance is losing energy
The substance is at equilibrium
Which of the following best describes the energy change during the boiling process on a heating curve?
Energy is absorbed to break intermolecular forces
Energy is released as intermolecular forces form
Energy remains constant
Energy is absorbed to increase temperature
What is the significance of the plateau observed in a heating curve?
It indicates a phase change where temperature remains constant
It shows a rapid increase in temperature
It represents a chemical reaction
It indicates the substance is cooling down
