Section 9 - Acids, Bases and pH

Question 1

What is a Bronsted-Lowry acid?

Answer 1

Proton donor

Question 2

What is a Bronsted-Lowry base?

Answer 2

Proton acceptor

Question 3

What is a strong acid?

Answer 3

An acid which dissociates almost completely in water. eg. HCl

Question 4

What is a strong base?

Answer 4

A base which dissociates almost completely in water. eg. NaOH

Question 5

What is a weak acid?

Answer 5

An acid which only slightly dissociatess in water. eg. CH₃COOH

Question 6

What is a weak base?

Answer 6

A base that only slightly dissociates in water. eg. NH3

Question 7

What occurs in acid-base equilibria?

Answer 7

The transferral of protons

Question 8

What is the ionic product of water equation?

Answer 8

K_w = [H⁺] [OH^-]

Question 9

What is Kw dependent on?

Answer 9

Temperature

Question 10

Why can Kw sometimes be written as [H⁺]²?

Answer 10

In pure water, there is always 1 H⁺ for ever OH^-

Question 11

What is the formula for pH?

Answer 11

-log[H⁺]

Question 12

What is the formula for conventration of H⁺?

Answer 12

10^-pH

Question 13

What is a strong monoprotic acid?

Answer 13

An acid where each molecule of acid will release one proton

Question 14

What is a strong diprotic acid?

Answer 14

An acid where each molecule of acid will release two protons

Question 15

What can be used to find the pH of a strong base?

Answer 15

Kw

Question 16

What is the acid dissociation constant?

Answer 16

K_a - used to find the pH of a weak acid

Question 17

What is the expression of Ka?

Answer 17

K_a = [products]/[reactants]

Question 18

What is the verticle section of a pH curve called?

Answer 18

Equivalence point or end point

Question 19

What type of indicator should you use for a weak acid-weak base titration?

Answer 19

pH meter

Question 20

Should you use methyl orange or phenolpthalein for a strong acid/strong base reaction?

Answer 20

Either

Question 21

Should you use methyl orange or phenolpthalein for a strong acid/weak base reaction?

Answer 21

Methyl orange

Question 22

Should you use methyl orange or phenolpthalein for a weak acid/strong base reaction?

Answer 22

phenolpthalein

Question 23

Why do you get a pH curve with two equivalence points for the titration of a strong diprotic acid with a strong base?

Answer 23

The reaction happens in two stages because the two protons are removed from the acid seperately.

Question 24

What is a buffer?

Answer 24

A solution that resists change in pH when small amounts of acid or base are added, or when it’s diluted

Question 25

What are acidic buffers made from?

Answer 25

A weak acid and one of its salts

Question 26

What are basic buffers made from?

Answer 26

A weak base and one of its salts

Question 27

Give 3 examples of buffers?

Answer 27

• Shampoos
• Biological Washing Powders
• Blood