Physical Properties and Changes of Matter

What is density?

The ratio of mass to volume

What is mass?

The amount of matter in a substance

What is volume?

The amount of space taken up by matter

What is a gram?

The metric unit of mass

Can density be used to identify a substance? Why?

Yes; density is unique to a substance's structure and doesn't change with sample size

What is a physical property? If it changes, will the substances identity change too?

An observable property; can change without changing the substance's identity

What is an intensive physical property?

A physical property (like density or boiling point) that does not depend on the amount of substance present

What is an extensive physical property?

A physical property (like mass or volume) that changes depending on the amount of substance present

What is the Kinetic Molecular Theory?

all matter is made of molecules in constant motion ^{(with temperature directly proportional to their average kinetic energy)}

What are the four states of matter?

Solid, liquid, gas, and plasma

What is absolute zero? (say temp in Kelvin); What happens?

0 K (–273°C), molecular motion theoretically stops

What is a solid (define the state; 2)? Define the molecules position and what type of motion is occuring?

A state with definite shape and volume; molecules are tightly packed with only vibrational motion

What is a liquid (define it’s state; 2)? Define the molecules (2)

A state with definite volume but no definite shape; molecules have both vibrational and translational motion

What is a gas? (define it’s state; 2) Define the molecules (2)

A state with no definite volume or shape; molecules move rapidly and are spread far apart

What determines the phase of a substance? (2)

Temperature and pressure

Are gases compressible? Are liquids/solids compressible?

Yes (gases are highly compressible); liquids and solids are generally non-compressible

What is melting? What is this caused by?

The change from solid to liquid, caused by adding heat

What is freezing? What is this caused by?

The change from liquid to solid, caused by removing heat

What is evaporation (boiling)? How is this caused?

The change from liquid to gas, caused by adding heat

What is condensation? How is this caused?

The change from gas to liquid, caused by removing heat

What is sublimation?

The transition of a substance from solid to gas without passing through the liquid state

What is deposition?

The change from gas directly to solid, without passing through the liquid state

What is the triple point?

The point of temperature and pressure where a substance's solid, liquid, and gas phases coexist

What is the critical point?

the point where the physical properties of the liquid and gas phases become indistinguishable