Unit 4

Question 1

K

Answer 1

equilibrium constant, do not include solids in equation

Question 2

le Chateliers principle

Answer 2

When a chemical system at equilibrium is disturbed in a change in a chemical property, the system adjusts in a way that opposes the change

Question 3

Change in [ ]

Answer 3

System will shift opposite way

Question 4

Thermal energy

Answer 4

System will shift towards the thermal energy q

Question 5

Decrease in volume (increase in pressure)

Answer 5

System will shift towards the side with less gas molecules

Question 6

What will not effect le Chateliers principle

Answer 6

Adding inner gasses, catalysts

Question 7

Q=K

Answer 7

System is at equilibrium

Question 8

Q>K

Answer 8

System must shift left to reach equilibrium

Question 9

Q

Answer 9

System must shift right to reach equilibrium

Question 10

Assumptions

Answer 10

If more than two decimal places over

Question 11

Arrhenius theory

Answer 11

Acids produce H+ ions when dissolved. Bases produce OH- when dissolved

Question 12

Bronsted- Lowry theory

Answer 12

Acids are proton (H+) donors, bases are proton receivers

amphoteric/ amphiprotic: a substance that can act as a B-L acid or base at the same time

Question 13

Conjugate acid pairs

Answer 13

A pair of substances who’s molecular formula differ by one H+

Question 14

Strong acid

Answer 14

100% ionized
Monotropic- releases only one H+
Ditropic- releases only two h+
Triprotic- releases only 3 H+

HCl, HBr, HI, H2SO4, HNO3, HCLO4

Question 15

Weak acid

Answer 15

An acid that is less than 100% ionized, in reality, much less than 50%

Question 16

Relative strength

Answer 16

The stronger the acid is, the weaker the conjugate base is etc.

Question 17

Kw

Answer 17

[H+][OH-]= 1.0X10^-14

Question 18

pH+pOH

Answer 18

=14=PKw

Question 19

pH

Answer 19

-log^[H+]

Question 20

pOH

Answer 20

-log^[OH-]

Question 21

Strong bases

Answer 21

100% ionized

Group 1 metal hydroxides + some others

Question 22

% ionization

Answer 22

(concentration of ion ionized/ concentration of solution) X100

Question 23

Measuring pH

Answer 23

litmus paper ( red= acid, base= blue)

Phenolphalein: colorless—–> 8-10

pH meter—-> based on electrical conductivity

Question 24

Haber processes

Answer 24

• Used to make ammonia, optimal conditions are in a closed system with a catalysts and very high temperatures

Question 25

Ka X Kb

Answer 25

Kw

Question 26

Salt hydrolysis

Answer 26

Reaction of ions with water to produce acidic or basic solutions a) if salt contains ions from strong acid and strong base the results will be neutral b) If the salt contains the conjugate acid of a weak base, the resulting solution will be acidic c) If the salt contains the conjugate base of a weak acid then the resulting solution will be basic d) When a salt contains ions from a weak acid and a weak base, the values of Ka and Kb are compared to determine acidity e) Amphoteric ions- Compare the values of Ka and Kb f) Metal oxides with water- bases Non metal oxides with water- acids

Question 27

Titration

Answer 27

To determine the amount of a specific chemical in a sample by adding a known amount of another substance

Question 28

Equivalence point

Answer 28

The point where the moles of acid equals the moles of base

Question 29

End point

Answer 29

The point where the indicator changes colour and the titration ends, usually just past the equivalence point

Question 30

The first law of thermodynamics (law of conservation of energy)

Answer 30

Energy can only be transformed, not created or destroyed

Question 31

Enthalpy changes and spontaneity

Answer 31

Exothermic reactions -H have a tendency to occur spontaneously

Question 32

Entropy, S

Answer 32

Degree of randomness in a system

Question 33

Predicting the signs of S

Answer 33

Gasses>> solutions > liquids>> solids. If the right side has more random states, S is positive.

Question 34

Second law of thermodynamics

Answer 34

When ever a spontaneous event takes place in our universe, it is accompanied by an overall increase in entropy

Question 35

Third law of thermodynamics

Answer 35

An absolute 0, the entropy of a perfectly ordered pure crystalline substance is zero

Question 36

Standard entropy (S)

Answer 36

Sum of Sf products- sum of Sf reactants

Question 37

Gibbs free energy

Answer 37

Maximum energy that is available to do work

Question 38

G

Answer 38

H-TS Gfinal- G initial

Question 39

Dynamic equilibrium

Answer 39

Forward and reverse rates are equal

Question 40

Solubility equilibrium

Answer 40

Salt no longer appears to dissolve at the saturation point, but on microscopic scale dissolving and crystallizing are still occurring

Question 41

Phase equilibrium

Answer 41

liquid- gas | Solid- liquid

Question 42

-H, +S

Answer 42

G is non spontaneous (+)

Question 43

+H, -S

Answer 43

G is spontaneous (-)

Question 44

Spontaneous G sign

Answer 44

-

Question 45

+H, +S

Answer 45

G is only negative at high temps

Question 46

-H, -S

Answer 46

Only spontaneous at low temps