4. Acids And Bases

Question 1

What is the bronsted and Lowry explanation of acids and bases?

Answer 1

Aid can donate a proton and base can accept a proton

Question 2

What is a conjugate base?

Answer 2

The base formed when a bronsted acid donates H+

Question 3

What is a conjugate acid?

Answer 3

Acid formed when a bronsted base accepts H+

Question 4

How can you use strength of acids/bases to predict direction of reactions?

Answer 4

stronger acid and stronger base —> weaker base and weaker acid

Question 5

What is the definition of a strong acid?

Answer 5

Dissociates completely in water

Question 6

What is meant by a weak acid?

Answer 6

Incomplete dissociation

Equilibrium established

Question 7

How is acid strength related to K?

Answer 7

Larger Ka implies a stronger acid

Question 8

What is the difference between a strong and weak base?

Answer 8

Strong bases dissociate completely in water while weak bases have incomplete dissociated, eqm established

Question 9

How is Kb related to base strength?

Answer 9

Larger kB—> stronger base

Question 10

What is the dissociation constant for water?

Answer 10

kw=[H3O+][OH-}

=1.00x10^-14

Question 11

What is pH?

Answer 11

pH= -log10[H3O+]

Question 12

What is pOH?

Answer 12

pOH = -log10[OH-]

Question 13

What does pH and pOH add to?

Answer 13

14.0

Question 14

How are Kw, Ka and Kb linked?

Answer 14

Kw= Ka x Kb

Question 15

How is pKa linked to pH?

Answer 15

pKa= pH + log10[HA]/[A-]

Question 16

What is the relationship between Ka and pKa?

Answer 16

The higher the Ka, the lower the pKa

Question 17

Why are acid base titrations done?

Answer 17

To accurately determine the amount of acid in a solution.

Question 18

Why can’t a pH meter just be used?

Answer 18

This only tells us the concentration of [H3O+]. So it is okay only if the acid is a strong acid or base.

Question 19

What is the general method of a titration?

Answer 19

Pipette a known volume of solution A into the conical flask.

Add 2-3 drops of indicator to the conical flask.

Solution B of known concentration (reacts with solution A) is added to the conical flask from the burette until the equivalence point is reached.

Question 20

What must the pH of the end point of the titration be matched to?

Answer 20

The pKa of the indicator

Question 21

What is the indicator range?

Answer 21

pKa plus or minus 1

Question 22

For strong base added to weak acid titration, what is there before the equivalence point?

Answer 22

The solution contains HA and A-

Question 23

For strong base added to weak acid titration, what is there at the equivalence point?

Answer 23

The solution contains A- (conjugate base)

It is basic

Question 24

For strong base added to weak acid titration, what is there after the equivalence point?

Answer 24

The solution contains excess OH- (from base)

Very basic

Question 25

For strong acid added to weak base titration, what is there before the equivalence point?

Answer 25

The solution contains HA and A-

Question 26

For strong acid added to weak base titration, what is there at the equivalence point?

Answer 26

The solution contains HA (conjugate acid)

It is acid so treat it as a weak acid

Question 27

For strong acid added to weak base titration, what is there after the equivalence point?

Answer 27

The solution contains excess H3O+ (from base)
Acidic
Treat as a strong acid