Unit 8: Acids And Bases

Question 1

Water autoionization constant?

Answer 1

K_w = 1.0 * 10^-14 = [H3O+][OH-], where pH = pOH = 7 at 25 degrees C

Question 2

Why in water, pH = pOH?

Answer 2

Because water has the same potential to release or accept a proton.

Question 3

K_a = ?

Answer 3

([H3O+][A-])/[HA], [A-] is the concentration of the conjugate base of the unionized acid, [HA] is the concentration of weak acid that hasn’t ionized yet.

Question 4

K_b?

Answer 4

([OH-][HB+])/[B], [HB+] is the concentration of conjugate acid.

Question 5

If you have a solution of the same concentration of strong acid and base, then the products will be?

Answer 5

H2O (l)

Question 6

In a strong acid and base solution, the pH of the resulting solution may be determined from the concentration of?

Answer 6

Excess reagent.

Question 7

If you mix a weak acid and strong base at equal concentrations, then the reaction equation?

Answer 7

HA (aq) + OH- (aq) <-> A- (aq) + H2O (l)

Question 8

Buffer solution?

Answer 8

An excess of weak acid [HA] compared to strong base [OH-].

Question 9

!!!!!!!How do you determine the pH of a buffer?

Answer 9

The Henderson-Hasselbalch (H-H) equation:

Question 10

If the strong base is in excess, how do you compute the pH of the solution?

Answer 10

Determining the moles of excess [OH-] and the total volume of the solution.

Question 11

If a weak base and a strong acid are mixed in equal concentrations, the reaction equation?

Answer 11

B(aq) + H3O+ (aq) <-> HB+ (aq) + H2O (l)

Question 12

If a weak base is in excess with a strong acid inside, then what type of solution is formed?

Answer 12

A buffer solution and the pH can be determined by the H-H- Equation.

Question 13

If a strong acid is excess in a solution with a weak base, how do you compute the pH?

Answer 13

By determining the moles of excess [H3O+] and the total volume of solution.

Question 14

For titrations of weak acids and bases, the half-equivalence point tells us?

Answer 14

Each species in the conjugate acid-base pair are equal in concentration, [HA] = [A-]. This means that pKa = pH

Question 15

Strong acids have weak/strong conjugate bases?

Answer 15

Weak, since they are stabilized by electronegativity, inductive effects, and resonance.

Question 16

An increase in electronegativity increase/decrease acid strength?

Answer 16

Increase

Question 17

pH > pKa, then you have?

Answer 17

More base

Question 18

If pH < pKa, then you have?

Answer 18

More acid.

Question 19

K_b is a base in?

Answer 19

Water

Question 20

The larger the pK_b, the weaker/stronger the base?

Answer 20

Weaker

Question 21

The larger the pK_a value, the weaker/stronger the acid?

Answer 21

Weaker

Question 22

pK_a = ?

Answer 22

-log(K_a), which is an inverse relationship

Question 23

K_w = ?

Answer 23

K_a * K_b

Question 24

If you have a strong acid or strong base, do you need to worry about equilibrium?

Answer 24

No

Question 25

Is X+ a conjugate acid/base of a weak acid/base?

Answer 25

Acid, base. Opposite for Y-

Question 26

•Acidic+neutral = •Basic+neutral = •Neutral+neutral =

Answer 26

•Acidic+neutral = acidic •Basic+neutral = basic •Neutral+neutral = neutral

Question 27

Buffer?

Answer 27

Any solution that maintains an approx constant pH despite small additions of acid and base

Question 28

Acid buffer?

Answer 28

Consists of a weak acid and its conjugate base supplied as sat. It buffers on acidic side of neutral

Question 29

Base buffer?

Answer 29

Consist of weak base and conjugate acid supplied as a salt. Buffers on the basic side of neutral

Question 30

In a buffer reaction, what happens to the products?

Answer 30

The conjugate acid or base follows its properties (e.g., donates or accept proton) to maintain pH due to stress in the products side.

Question 31

How many conjugates do you have in buffers?

Answer 31

Two conjugates.