Chapter 11

Question 1

What differentiates the phases of matter?

Answer 1

Density, Shape, Volume, Inter-molecular Forces

Question 2

Gas

Answer 2

Low Density, Shape of Container, Volume of Container, Weak Inter-molecular Forces

Question 3

Liquid

Answer 3

Medium Density, Shape of Container, Fixed Volume, Medium Inter-molecular Forces

Question 4

Solid

Answer 4

High Density, Fixed Shape and Volume, Strong Inter-molecular Forces

Question 5

How to force a change from Gas to Liquid

Answer 5

Increase pressure, lower temperature

Question 6

How to force a change from liquid to solid

Answer 6

Lower temperature

Question 7

How to force a change from Gas to Solid

Answer 7

Lower temperature

Question 8

What is the weakest inter-molecular force?

Answer 8

London Dispersion Force

Question 9

London Dispersion Forces

Answer 9

As electron move around in their orbitals in an atom, at any given moment more of them may be on one side of the atom than the other. It results in the atom having a dipole moment which induces a dipole in the next atom over creating a weak attraction between the atoms

Question 10

Where do Dispersion Forces exist?

Answer 10

Every Chemical System

Question 11

What factors determine how big the dispersion force is?

Answer 11

Molar Mass
Molecular Shape
Size

Question 12

How does Molar Mass affect Dispersion Forces?

Answer 12

Heavier molecules have more dispersion interactions

Question 13

How does molecular shape affect Dispersion Forces?

Answer 13

Longer, straighter molecules ten to have more dispersion interactions than globular ones

Question 14

How does Size affect Dispersion Forces?

Answer 14

Atoms that have lower electronegativities and ionization energies are easier to polarize and have stronger dispersion forces

Question 15

Dipole Force

Answer 15

Molecules line up so that the negative end of one is close to the positive end of another. Polar molecules have a higher melting and boiling point than non-polar molecules

Question 16

Where do Dipole Forces exist?

Answer 16

All molecules that have a permanent dipole

Question 17

Miscibility

Answer 17

Ability of liquids to mix without separating into two phases

Question 18

What is needed to mix polar and non-polar molecules?

Answer 18

Emulsifier

Question 19

When does Hydrogen Bonding occur?

Answer 19

Only in certain molecules that have extremely strong dipole-dipole interactions

Question 20

How strong are hydrogen bonds?

Answer 20

Very strong

Question 21

Why are hydrogen bonds so strong?

Answer 21

The very electronegative atoms cause the hydrogen bonded to them to have a large partial positive charge

Question 22

Ion-Dipole Forces

Answer 22

Interaction between an ion and a polar compound
Responsible for ionic solids dissolving in water
Strongest inter-molecular force

Question 23

Why do something float on water?

Answer 23

Liquids form ‘a skin’ along their surface, called surface tension

Question 24

Surface Tension

Answer 24

Water molecules on the surface have a higher potential energy than those in the interior.
The liquid then tries to minimize the number of surface molecules, resisting changes that would increase its surface area

Question 25

What does the rate of Vaporization depend on?

Answer 25

Temperature of the liquid
Surface area of the liquid
Volatility of the liquid (inter-molecular forces)

Question 26

Critical Point

Answer 26

Point where the vapour and the liquid have the same density

Question 27

What happens at Critical point?

Answer 27

Forms new phase: Supercritical fluid

Question 28

Sublimation

Answer 28

Solid to Gas without going through the liquid phase

Question 29

Deposition

Answer 29

Opposite of Sublimation

Question 30

What do phase diagrams show?

Answer 30

Which phase is most stable under certain conditions

The conditions that favour each phase