lecture 1 - gases

Question 1

gases can be composed of

Answer 1

molecules - O2 N2
atoms - He Ar

Question 2

molecules and atom gases behave the same so we call them both

Answer 2

particles

Question 3

physical properties of the three phases of matter

Answer 3

solid:
✅ condensed
❌ fluid

liquid:
✅ condensed
✅ fluid

gas:
❌condensed
✅fluid

Question 4

what does a condensed phase mean

Answer 4

difficult to compress

solid, liquid

hard to clap ur hand when theyre stuck in cement or under water

easy to clap ur hands in air

Question 5

what does a fluid phase mean

Answer 5

it flows easily

liquid flows easily and so does gas

liquid does not flow easily

Question 6

phases of matter according to microscopic criteria

Answer 6

particle sep similar to particle size

particles translating relative to eachother

Question 7

what does particle separation similar to particle size mean

Answer 7

is the distance between particles similar to the size of the particle

Question 8

what does particles can translate relative to eachother mean

Answer 8

can particles move

Question 9

phases and their microscopic criteria

Answer 9

sep as big as size
solid: ✅
liquid:✅
gas: ❌ gas particles can be very spaced out

translate relative to eachother
solid:❌
liquid:✅
gas:✅

Question 10

solid particles cannot translate relative to eachother but they are still not stationary as they can still

Answer 10

vibrate

Question 11

ideal gas assumptions

Answer 11

particles have 0 volume
no interparticle forces

these are untrue

Question 12

why do the untrue ideal gas assumptions lowkey make sense tho

Answer 12

gas with low density: weak inter-particle forces

particle vol will be very small compared to the total volume (if density is low enough)

Question 13

what is p

Answer 13

pressure
Pa

Question 14

what is v

Answer 14

volume
m3

Question 15

1L is how many dm3

Answer 15

1
1L = 1dm3

Question 16

what is T

Answer 16

thermodynamic temp
in Kelvin

Question 17

from c to k temp we must add

Answer 17

273.15

Question 18

n is

Answer 18

number of moles
in mol

Question 19

R is

Answer 19

gas constant
8.3145

Question 20

what is R equal to

Answer 20

boltzman constant
and
avogadros constant

Question 21

pressure is directly proportional to

Answer 21

1/V

Question 22

volume is directly proportional to

Answer 22

T

Question 23

V is directly proportional to

Answer 23

n

Question 24

ideal gas equation

Answer 24

pv = nrt

obeyed by many low density gases

equation of state for ideal gases

Question 25

p Vm = RT

Answer 25

Vm = molar volume (V/n)
Vm units: m3 mol-1

Question 26

consequence of ideal gases

Answer 26

no matter the identity of the gas, they behave the same way.

properties are determined by moles and not identity of the gas

Question 27

daltons law

Answer 27

total pressure of a mixture of gases is equal to the sum of each of their partial pressures

Question 28

what is the partial pressure of a gas

Answer 28

the pressure it exerts if it was by itself in the same volume

Question 29

ideal gas equation for 2 ideal gases

Answer 29

p tot = n tot (RT) / V

or

ptot = na (RT)/V + nb (RT)/V

Question 30

partial pressure equation for a gas

Answer 30

pp a = xa x ptot

xa= mole fraction (na/ntot)

Question 31

2 collisions between gas particles

Answer 31

elastic
inelastic

Question 32

elastic collisions

Answer 32

conserve total kinetic energy

Question 33

inelastic collisions

Answer 33

change total kinetic energy

Question 34

both collisions conserve…

Answer 34

momentum

Question 35

what type of collision do atomic gases usually have

Answer 35

elastic
conserve kinetic energy

Question 36

what type of collisions do molecular gases usually have

Answer 36

inelastic
energy is usually converted to rotational or vibrational energy.

reverse can also occur: rotational and vibrational into kinetic when collisions occur

Question 37

on average collisions are usually

Answer 37

elastic

Question 38

what generates the pressure of a gas

Answer 38

its collisions with the vessel walls

Question 39

sum of partial pressures for a mix of ideal gases

Answer 39

pressure of the mixture

Question 40

ideal gas equation refers to all

Answer 40

low density gases