What is the melting point of a crystalline solid?
The temperature at which the forces holding its crystal lattice together are broken and it becomes a liquid.
What is vaporization?
The process by which a liquid changes to a gas or vapor.
What is boiling point?
The temperature at which the vapor pressure of a liquid equals the external or atmospheric pressure.
What is sublimation?
The process by which a solid changes directly to a gas with first becoming a liquid.
What is freezing point?
The temperature at which a liquid is converted into a crystalline solid.
True or False: Precipitation, clouds, and fog are all the result from condensation?
True
What happens when a water vapor molecule loses energy?
It's velocity decreases.
What is condensation?
The process by which a gas or a vapor becomes a liquid.
True or False: Combustion is the reaction of a fuel with Oxygen?
True.
What two variables combine to control the phase of a substance?
Temperature and Pressure.
True of False: Only chemical reactions absorb or release heat?
False. Many processes other than chemical reactions absorb or release heat, such as, vaporization or fusion.
What happens when water vapor comes in contact with a cold window in winter?
It forms a solid deposit in the window called frost.
What is a thermochemical equation?
A balanced chemical equation that includes the physical states of all reactants and products and the energy change.
What is evaporation?
When vaporization occurs only at the surface of a liquid.
What is Molar Enthalpy (Heat) of Fusion?
The heat required to melt one mole of a solid substance.
What is vapor pressure?
True or False: Condensation is the reverse of Deposition?
False. The reverse of Deposition is Sublimation.
What is a phase change?
A transition of matter from one state to another.
What is the Enthalpy (Heat) of Combustion?
The enthalpy change for the complete burning of one mole of the substance.
True or False: Condensation and Evaporation are both endothermic reactions?
False. During Condensation, the molecules give up their heat energy, making it an exothermic process.
True or False: Vaporizing and Melting a solid are endothermic processes?
True.
What is Molar Enthalpy (Heat) of Vaporization?
The heat required to vaporize one mole of a liquid.
What is desposition?
The process by which a substance changes from a gas or vapor to a solid without first becoming a liquid.
What is the triple point?
The point on a phase diagram that represents the temperature and pressure at which three phases of a substance can coexist.
What is a phase diagram?
A graph of pressure versus temperature that shows in which phase a substance exists under different conditions of temperature and pressure.