All Flashcards
What is the effect of adding energy to a solid at its melting point?
The solid will begin to melt, transitioning to the liquid phase, without a change in temperature until all of the solid has melted.
What is the effect of increasing the temperature of a liquid at its boiling point?
The liquid will begin to vaporize, transitioning to the gas phase, without a change in temperature until all of the liquid has vaporized.
What is the effect of increasing pressure on a substance near its melting point?
For most substances, increasing pressure increases the melting point. However, water is an exception; increasing pressure decreases its melting point.
What is the effect of increasing temperature on the volume of a gas (at constant pressure)?
The volume of the gas increases (Charles's Law).
What is the effect of strong intermolecular forces on the heat of vaporization?
Stronger intermolecular forces lead to a higher heat of vaporization because more energy is required to overcome these forces and change the substance from a liquid to a gas.
On a typical heating curve, what do the slopes represent?
The slopes represent the change in temperature as heat is added within a single phase (solid, liquid, or gas).
On a typical heating curve, what do the plateaus represent?
The plateaus represent phase changes (melting/freezing, boiling/condensation) where the temperature remains constant as heat is added or removed.
On a phase diagram, what area represents the solid phase?
The solid phase is generally located in the high pressure and low temperature region of the phase diagram.
On a phase diagram, what area represents the liquid phase?
The liquid phase is generally located in the moderate pressure and moderate temperature region of the phase diagram.
On a phase diagram, what area represents the gas phase?
The gas phase is generally located in the low pressure and high temperature region of the phase diagram.
Define 'heat of fusion' (H).
The energy required for a substance to change from a solid to a liquid.
Define 'heat of vaporization' (Hₜ).
The energy required for a substance to change from a liquid to a gas.
Define 'triple point' on a phase diagram.
The temperature and pressure at which solid, liquid, and gas phases coexist in equilibrium.
Define 'critical point' on a phase diagram.
The point beyond which a distinct liquid phase no longer exists; the substance becomes a supercritical fluid.
Define 'specific heat capacity'.
The amount of heat required to raise the temperature of one gram of a substance by one degree Celsius.
Define 'endothermic process'.
A process that absorbs heat from its surroundings.
Define 'exothermic process'.
A process that releases heat to its surroundings.