Unit 5:Gases and Intermolecular Forces Flashcards by Tay D.

whats the STP for gases

o degrees Celcius and 1 atm

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equation for ideal gas law

PV = nRT, where R = 0.08206 L∙atm∙mol-1K-1

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what are each mixture of gas considered?

We can consider each gas in a mixture separately. Each gas in a mixture has an amount (i.e. number of moles) and its own “partial pressure”.

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whats the partial pressure of gas in a mixture

The partial pressure of a gas in a mixture is the pressure exerted by only that gas. The total pressure of the mixture equals the sum of all the partial pressures.

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how can you describe a mixture of gases

In the same way, you can describe a mixture of gases in terms of partial pressures. If you have a mixture of oxygen that has a partial pressure of 1 atm and helium that has a partial pressure of 2 atm, the total pressure is 3 atm.

PO2 = 1 atm
PHe = 2 atm
Ptotal = 3 atm

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how does the partial presssure of gas relate to gas inside a container (I probably worded this weird but IDK what I’m doin)

The partial pressure of a gas is the pressure that gas would exert if that amount of the gas were all alone in the container.

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Dalton’s law of partial pressures

states that the total pressure in a container equals the sum of the individual pressures:

Ptotal = P1 + P2 + P3 + etc….

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vapor pressure

The vapor pressure of a liquid is the pressure that the gaseous form exerts when the maximum amount of the liquid becomes a gas. The vapor pressure of water at 20 °C is 17.5 torr.

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two equations to calculate humidity

humidity= 100%(amount of water in the air/the maximum amount of water that can be in the air)

humidity=100%(partial pressure
of water in the air/vapor pressure of water)

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describe solids

definite volume
definite shape
often ordered
high density
atoms can vibrate

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describe liquids

definite volume
indefinite shape
not ordered
high density
atoms can move

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describe gases

indefinite volume
indefinite shape
not ordered
low density
atoms can move

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What is P=F/A

Pressure = force divided by area

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kinetic molecular theory

Gases are composed of rapidly moving particles that collide elastically. They create forces when they bump into things.

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whats an ideal gas

“Ideal” gas molecules/atoms do NOT:

1) occupy any space
2) attract or repel each other

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what causes air pressure

air atoms and molecules bumping into stuff

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what does every variable in PV=nRT mean

p-pressure
v- volume
n- number of moles
r- 0.082-6
T- temperature

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what does every varibale in L-atm-mol^-1-k^-1 mean

l- liters
atm- atmospheric pressure
mol- moles
k- kelvin’s temp

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what is STP used for

used for reference calculations

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what does “like dissolve like”mean

things of one group dissolves for things of that same group

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what does water dissolve

ionic compunds
things that can H-bond
hydrophillic

what does oil dissolve

non-polar covalent
things that can’t H-bond
hydrophobic

hydrophilic heads are polar or non-polar

hydrophilic heads are polar

hydrophobic heads are….

non-polar

why dont oil and water mix

grease is non-polar and clumps together

what is viscosity related to

intermolecular forces molecular size temperature

what causes the states of matter

``` temperature intermolecular forces (IMF) ```

temperature

Temperature is a measure of the average kinetic energy of atoms

whats the equation for KE

KE=1/2mv

how active are all matter above absolute zero

All matter above absolute zero is in motion. The higher the temperature, the faster the atoms move.

why do gas atoms fly around without sticking close to other atoms?

Gas atoms fly around without sticking close to other atoms because their kinetic energy is much larger than the intermolecular forces between them.

why does solid atoms stick together/very closely and don't move(only vibrate)

Solid atoms stick together very closely and don’t move around (they only vibrate) because their kinetic energy is much smaller than the intermolecular forces between them.

why does liquid atoms stay close to each outher but mover around freely?

their kinetic energy is comparable to the intermolecular forces between them.

kinetic-molecular gas theory

Ideal gas molecules/atoms do NOT: 1) occupy any space 2) have any intermolecular forces

what gases are NOT ideal

1) ones with strong IMF 2) ones at low temperature 3) ones at high pressure

describe molecular solids

Molecular solids are held together only by intermolecular forces. Because intermolecular forces are weak, molecular solids are usually soft.

are ionic solids brittle or strong? Why

brittle b/c of repulsion, slight shift of the atoms

what are Dipole-Dipole forces

Polar molecules have charges much smaller than + or – 1, so dipole-dipole forces are much weaker than ion-ion forces.

how strong are dipole-dipole forces compared to ion-ion

dipole-dipole forces are much weaker than ion-ion forces.

what are 3 charactersistics of hydrogen bonding

1) NOT real bonds 2) extra strong dipole-dipole attractions 3) in molecules with N-H, O-H, F-H

instantaneous dipole moment

Because electrons are always in motion, at any instant a non-polar molecule can have an instantaneous dipole

induced dipole moment

An instantaneous dipole moment can induce a dipole moment in a nearby molecule and cause an attraction

London Dispersion

The attraction between the instantaneous dipole moment and the induced dipole moment is called London Dispersion Forces. This force exists between any type of molecule over the entire surface of the molecules! Larger molecules = stronger London forces

name all the intramollecular forces

covalent and ionic bonds

list all the intermolecular forces

hydrogen bonds dipole-dipole bonds london forces

list the molecular forces in order of strongest to weakest

covalent bonds, ionic bonds, hydrogen bonds, dipole-dipole forces, london forces

supercritical fluids

Above the critical temperature and pressure, a substance is said to exist as a supercritical fluid, which like a gas has the volume of its container but can have high densities like liquids. Supercritical fluids can dissolve things (like a liquid) and effuse through solids (like a gas).

whats critical temperature

The critical temperature (TC) of a substance is the highest temperature at which a liquid can exist. Above the TC, there is no distinct transition between liquid and gas!

name the type of force attraction molecular forces have and give examples

Material: molecular Force of Attraction: Intermolecular forces Ex: water, air, organic materials, wood, plastic

name the type of force attraction of metallic materals and give examples

``` material: metallic force of Attraction: metallic bonds Ex: iron steel, copper, bronze, mecury, sodium ```

name the type of force attraction ionic materials have and give examples

material: ionic force of attraction: ionic bonds Examples: salt, most rocks, most gems ceramics

name the type of force attraction network materials have and give examples

material: network force of attraction: covalent ex: diamond, graphite, boron, silicon