Chemistry Exam- Chapter 11/12

Question 1

What are the four intermolecular bonds in order of increasing strength?

Answer 1

london dispersion
dipole-dipole
ion-dipole
hydrogen bonding
ion-ion

Question 2

Viscosity increases with: ___ intermolecular forces, which is cause by ___ in molecular weight and a(n) ___ in temperature.

Answer 2

stronger, increase, increase

Question 3

Viscosity is…

Answer 3

the resistance to flow

Question 4

Endothermic phase changes

Answer 4

melting
vaporization
sublimation

Question 5

Exothermic phase changes

Answer 5

freezing
condensation
deposition (gas to solid)

Question 6

What is supercritical fluid?

Answer 6

When critical temperature is reached and the properties of the gas and liquid are the same.

Question 7

True or False

1. Ionic compounds are conductors ONLY in aqueous form
2. Molecular moles conduct electricity

Answer 7

True
False

Question 8

Example of a covalent network solid

Answer 8

Diamond and graphite

Question 9

Gases have __ solubility in water.

Answer 9

low

Question 10

Gases that are more ___ are more likely to have higher solubility.

Answer 10

polarizibility

Question 11

Solubility of gases in water ___ with increasing temperature and ___ with increasing pressure.

Answer 11

decreases, increases

Question 12

Henry’s Law

Answer 12

Gas solubility (M) = K*P(gas)
k = constant
P(gas) = partial pressure of gas

Question 13

Solubility of a gas in a liquid is directly proportional to…

Answer 13

its pressure.

Question 14

Parts by mass:
(%w/w) (ppm) (ppb)

Answer 14

mass of solute/mass of solution

Question 15

Parts by volume
(%v/v) (ppmv) (ppbv)

Answer 15

vol. of solute/vol. solution

Question 16

Molarity:
(M/L)

Answer 16

mol of solute/vol. solution

Question 17

Molality:
(mol/kg)

Answer 17

mol of solute/mass of solvent

Question 18

How to calculate ppm

Answer 18

(mass A/ total mass) * 10^6

Question 19

How to calculate ppb

Answer 19

(mass A)/total mass) *10^9

Question 20

Why the vapor pressure of a solution lower than that of the pure solvent?

Answer 20

As the concentration of nonvolatile solutes are added, it makes it harder to escape the vapor phase.

Question 21

Trend between vapor phase and volatility.

Answer 21

High volatility –> High vapor pressure

*high vapor pressure means more molecules are escaping to the vapor phase

Question 22

Raoult’s Law

Answer 22

Pa=(mol fraction solvent) (normal vap. p)

Question 23

Only ideal solutions obey Raoult’s Law…
What makes a solution ideal?

Answer 23

a) solute concentration is low
b) solute and solvent have a similar molecular size
c) similar intermolecular attractions between solute and solvent

Question 24

When would you see that the attraction between the solvent and solute is very strong but the vapor pressure is low?

Answer 24

Strong H-bonds between solute and solvent.

Question 25

WHAT DO YOU HAVE TO CHECK FOR IF YOU ARE CALCULATING FREEZING/BOILING POINT??????????

Answer 25

FOR IONS!!!! AND MULTIPLY THEM WITH MOLALITYYYYY!!!!

Question 26

What is the Van't Hoff Factor and when do we use it?

Answer 26

change T (f) = Kf *m* i i= factor When we have to factor reassociation

Question 27

Hypertonic

Answer 27

When the cell has a lower concentration than its surroundings.

Question 28

Hypotonic

Answer 28

When the cell has a higher concentration than its surroundings.

Question 29

Define colloid and give examples

Answer 29

- an evenly distributed heterogenous mixture -milk, cream, emulsion

Question 30

Osmotic pressure calculation

Answer 30

pi = (n/V) MRT n=moles M=molarity R= 0.08206 T = Kelvin

Question 31

What do the segments on a heating/cooling curve represent?

Answer 31

horizontal segments: where intermolecular forces are broken/distance between molecules increase sloped segments: represent the heat capacity of a solid, liquid, or gas

Question 32

___ point is when three phases exist at equilibrium

Answer 32

Triple

Question 33

When you calculate boiling point elevation and freezing point depression, what do you have to consider?

Answer 33

IONS!!!! The number of ions you have is what you multiply with the molality. This is known of the Van't Hoff Factor.

Question 34

There is a ___ relationship between molality and boiling point elevation.

Answer 34

direct

Question 35

3 colligative properties

Answer 35

1. Freezing point depression 2. Boiling point elevation 3. Osmotic pressure formula