Unit 3

Question 1

4 physical properties of gases

Answer 1

Highly compressible

Infinity miscible
(Infinity form a homogeneous mixture)

Thermally expandable

Low density

Question 2

Why does a gas exert pressure on its environment

Answer 2

Because the molecules are in constant motion

Question 3

Pressure formula and what is it measured in

Answer 3

P= Force/area

Measured in N/m^2 = 1 Pa

Question 4

What is boyles law and formula

Answer 4

At constant temp (and moles) pressure is inversely proportional to volume

P1V1 = P2V2

Question 5

What is Charles’s law and formula

Answer 5

At constant pressure, volume is directly proportional to temp

V1/T1 = V2/T2

Question 6

What is avagadro’s law and formula

Answer 6

At constant temp and pressure, volume is directly proportional to the number of moles

V1/n1 = V2/n2

Question 7

Small n equation

Answer 7

n = m/M

Question 8

Gas density formula

Answer 8

d = m/V

Question 9

Total pressure formula

Answer 9

Pt = Pa + Pb + Pc

Question 10

Mole fraction formula

Answer 10

Xa = na/n total

Question 11

What is the mole fraction also equal to

Answer 11

Pa/P Total

Question 12

Do gas particles have kinetic and potential energy

And why

Answer 12

Only kinetic

Particles are in continuous random motion and have no inter particle forces

Question 13

Do gas particles have attraction or repulsion

Answer 13

No

Question 14

Gases are made up of particles with no defined _____

And why

Answer 14

Volume

Particle size is so small compared to the distance separating them so it’s negligible

Question 15

Why does the total energy remain CONSTANT

Answer 15

Collisions are elastic

Question 16

When is the average kinetic energy the same, regardless of the gas

Answer 16

When the temp is the same

Question 17

Formula for kinetic energy of one particle of gas

Answer 17

1/2 mu ^2

Question 18

Average kinetic energy for one mole of particles formula

Answer 18

K = (Na)(1/2)mu^-2

Question 19

Average kinetic energy with respect to RT

Answer 19

k = (3/2) RT

Question 20

What is Urms and what’s the formula for it

Answer 20

Root mean speed

Urms = sqrt (3RT/M)

M is in kg/mol

Question 21

Do gases have high or low Urms

Answer 21

High (moving faster)

Question 22

What is diffusion

Answer 22

Process by which a substance mixes with one or more substances following the movement of particles

Question 23

What is compression factor

And formula

Answer 23

Ratio of the molar volume of a gas to the molar volume of an ideal gas at the same temp and pressure

cf = PV/nRT

Question 24

Particles in a REAL gas experience _____ inter particle attraction

Answer 24

Weak

Question 25

Particles in a REAL gas occupy a ___ volume

Answer 25

Finite

Question 26

What equation shows how real gases behave

Answer 26

P = nRT/V-nb - a(n/V)^2 nb = correction to volume (n/V)^2 = correction to pressure

Question 27

When is ideal gas behaviour observed

Answer 27

At low pressure and high temp

Question 28

The change in states between solids and liquids is due to a modification in _____ ____ And explain

Answer 28

Intermolecular forces The energy supplied is used to overcome the imf until the molecules can free themsevles and move form one phase to another

Question 29

What is a hydrogen bond

Answer 29

Hydrogen bonds to NOF

Question 30

The stronger the imf, the higher the ___ and ___

Answer 30

Mp Bp

Question 31

What is the energy required to overcome a hydrogen bond between

Answer 31

10-40 kJ/mol

Question 32

London dispersion creates ____________\

Answer 32

An instantaneous intermolecular attraction that is short lived and weak

Question 33

How much bigger does the M value have to be when looking at mp

Answer 33

Three times bigger

Question 34

How does size affect mp

Answer 34

Biggest np means most polarizable means highest IMF means highest BP

Question 35

What is surface tension

Answer 35

The resistance of a liquid to increase in surface area

Question 36

The higher the surface tension the higher the _____

Answer 36

IMF

Question 37

What is capillarity

Answer 37

Refers to the spontaneous rising or descent of a liquid in a capillary tube

Question 38

What is wetting

Answer 38

Ability of a liquid to maintain contact with a surface

Question 39

What do capillarity and wetting depend on

Answer 39

Cohesive and adhesive forces

Question 40

What are cohesive forces

Answer 40

IMF between molecules of a liquid

Question 41

What are adhesive forces

Answer 41

Forces of attraction between molecules of the liquid and the particles present on the surface of the tube

Question 42

What is the only liquid that chases a convex meniscus

Answer 42

Mercury

Question 43

When does a concave mensisucs happen

Answer 43

Adhesive > cohesive

Question 44

When does a convex mensisus form

Answer 44

cohesive > adhesive

Question 45

What does capillary attraction look like

Answer 45

Tube in bowl of water has water HIGHER than bowl and mensisucs is concave

Question 46

What does capillary repulsion look like

Answer 46

Tube in bowl of water has water LOWER than bowl and mensisucs is convex

Question 47

What is viscosity

Answer 47

Resistance of a liquid to flow

Question 48

High viscosity means high _____

Answer 48

IMF

Question 49

Are long chain hydrocarbons polar or np

Answer 49

Np

Question 50

What is vapour pressure of liquids

Answer 50

Gfa