Unit 2: Gases & Moles

Tiny particles with space between

Matter is composed of…

Constant, random motion

The particles that make up matter are in…

Organization and freedom of motion of the particles

Determines state of matter

Determines the large scale, observable properties of matter

Organization and freedom of motion of the particles also…

Strength of attractive forces (intermolecular forces) between particles

Organization and freedom of motion of particles comes from..

Endothermic

Energy in, makes particles move faster, spread out

Exothermic

Energy out, makes particles slow down, move together

Solid - no

Liquid - yes

Gas - yes

_____ state of matter has fluidity

Solid - no

Liquid - no

Gas - yes

_____ state of matter has Compressibility

Solid - defined

Liquid - undefined

Gas - undefined

_____ state of matter has defined/undefined shape

Solid - defined

Liquid - defined

Gas - undefined

_____ state of matter has defined/undefined volume

Temperature and pressure

What two conditions can be changed that allow you to induce phase changes?

The colder something gets, the closer the molecules come, while the opposite occurs when heating things up. The state of matter changes depending on how much space there is between molecules.

How does temperature changes impact the phase of matter

Melting

Solid to liquid

Vaporization

Liquid to gas

Deposition

Gas to solid

Sublimation

Solid to gas

Condensation

Gas to liquid

Freezing

Liquid to solid

Physical change

Any change in appearance that does NOT create a new substance

Chemical change

Involves breaking or forming chemical bonds to create new/different substances

Solid

Which phase of matter would you expect to have the strongest intermolecular forces?

Gas

Which phase of matter would you expect to have the weakest intermolecular forces?

Sublimation

Which of the 6 possible phase changes are endothermic

Deposition

Which of the 6 possible phase changes are exothermic

One place where all three phase can coexist in equilibrium

The triple point

The place beyond which gases and liquids are indistinguishable fluids

The critical point

Low pressure and low temperature

Under what conditions can sublimation occur?

Remains the same

During phase changes, what does the temperature do?

True

Putting energy in takes you up the heating curve (endo)

True

Taking energy out brings you down the cooling curve (exo)

Boiling - liquid to gas

Which phase change requires the most energy

Joules

Metric unit for energy

Q = mΔH

Equation for finding how much heat is absorbed during phase changes

It’s solid to liquid

ΔHfus is used in the equation when…

It’s liquid to gas

ΔHvap is used in the equation when…

Dalton’s Law

Total pressure in a container is SUM of the pressures of the individual gasses

Patm=Ph20+Pgas

Ideal Gas

A hypothetical model of “perfect” gas behavior, most gases come close at low pressures and high temperatures

Pressure in atm(Volume in L)=moles(R)(Temp in K)

If you have more than one P, V, or/and T

Combined Gas law

P1V1/T1 = P2V2/T2

If you have moles or particles or only ONE P, V, or T

Use ideal gas law

If you have anything about vapor pressure and partial pressures

Daltons law