Vocabulary
Pictures
Questions
Fill In The Blank
Challenge
100
What is a phase change?
A transition of matter from one state to another.
100
What pahse change does this picture represent?
Condensation
100
What is the phase change when the substance changes from a liquid to a solid.
Freezing
100
The ____ ____ of a crystalline solid is the temperature at which the forces holding at crystal lattice together are broken and it becomes a liquid
Melting point
100
What does this thermochemical equation represent?
H2O(s)→H2O(l)
One mole of ice melts to form one mole of water.
200
What is a physical change?
A type og change that alters the physical properties of a substance but does not change it's composition.
200
What phase change is this picture representing?
Melting
200
What is the phase change when a substance changes back from the solid to the liquid.
Melting
200
The temperature at which the vapor pressure of a liquid equal the external or atmospheric pressure which is called the ______ ______.
Boiling Point
200
What does this thermochemical equation represent? H2O(l)→H2O(g)
One mole of water is converted to one mole of water vapor
300
What is a chemical change?
A process involving one or more substances; also called a chemical reaction.
300
What phase change does this picture represent?
Vaporization (evaporation)
300
What is the phase change called when a the substance changes from a gas to a liquid.
Condensation
300
The ____ ____ is the temperature at which a liquid is converted to a crystalline solid
Freezing Point
300
Because vaporizing a liquid and melting a solid are endothermic processes, are their ΔH values positive or negative?
Positive
400
What is molar enthalapy (heat) of vaporization?
The amount of heat required to vaporize one mole of a liquid.
400
What phase change does this picture represent?
Freezing
400
The phase change when a solid goes directly to a gas is called
Sublimation
400
The pressure exerted by a vapor over a liquid is called ____ ____
Vapor Pressure
400
The _____ _____ is the point on a phase diagram the represents the temperature at which three phases of a substances can coexist
Triple Point
500
What is molar enthalapy (heat) of fusion?
The amount of heat required to melt one mole of a solid substance.
500
What phase change does this picture represent?
Sublimation
500
What phase change occurs when the substance changes directly from a gas to a solid without going through the liquid phase?
Deposition
500
A _____ _____ is a graph of pressure verus temperature that shows in which phase a substance exists under different conditions of temperature and pressure.
Phase Diagram
500
Explain why dew forms on cool mornings.
During the night the water in the air condenses and dew forms on the blades of grass. This occurs becuase the formation of a hydrogen bond releases thermal energy and indicates a chnage from the vapor phase to the liquid phase