Ionic Product of Water

Question 1

What is the dissociation of water?

Answer 1

when one water molecule acting as an acid and another molecule acting as a base form a conjugate acid and conjugate base

Question 2

What is the equation for the ionic product of water?

Answer 2

Kw=[H₃O⁺][OH⁻]

Question 3

What is the value of the ionic product of water?

Answer 3

Kw=1x10⁻¹⁴

Question 4

What is the pH scale?

Answer 4

a measure of the concentration of hydrogen ions in the solution

Question 5

How can the pH of an aqueous solution be calculated?

Answer 5

pH=-log[H]

Question 6

What can be said about the concentration of hydrogen and hydroxide ions in pure water?

Answer 6

they are equal

Question 7

What is an acid?

Answer 7

any substance capable of donating a proton

Question 8

What is a base?

Answer 8

any substance capable of accepting a proton

Question 9

What can be said about water molecules?

Answer 9

water is amphoteric-it can act as an acid or a base

Question 10

What is Ka?

Answer 10

a measure of the strength of an acid

Question 11

What are examples of strong acids?

Answer 11

• hydrochloric acid
• sulfuric acid
• nitric acid

Question 12

What are examples of weak acids?

Answer 12

• ethanoic acid
• carbonic acid
• sulphurous acid
• ALL CARBOXYLIC ACIDS

Question 13

Strong acid

Answer 13

ka>1

Question 14

Weak acid

Answer 14

ka<1

Question 15

How can the pka of a solution be expressed?

Answer 15

pka=-logka

Question 16

What can be said about a strong acid?

Answer 16

a strong acid will have a high ka and a low pka

Question 17

What will a weak acid have?

Answer 17

a low ka value and a high pka value

Question 18

What are examples of strong bases?

Answer 18

metal hydroxides

Question 19

What are examples of weak bases?

Answer 19

• ammonia

* ammines

Question 20

What is a buffer solution?

Answer 20

one in which the pH remains constant when small amounts of acid or base is added

Question 21

What is the pH of an acidic buffer?

Answer 21

<7

Question 22

What is an acidic buffer made from?

Answer 22

a weak base and one of its salts

Question 23

What is the pH of a basic buffer?

Answer 23

> 7

Question 24

What is a basic buffer made from?

Answer 24

a weak base and one of its salts

Question 25

What are indicators?

Answer 25

dyes that are sensitive to pH

Question 26

What can indicators be used to determine?

Answer 26

the end-point in an acid-alkali titration

Question 27

When is the colour change distinguishable using an indicator?

Answer 27

when [HIn] and [In] differ by a factor of 10

Question 28

What is the equivalence point?

Answer 28

where the graph is almost vertical

Question 29

How does a basic buffer work?

Answer 29

when an alkali is added, the large reserve of the ammonium chloride ions combine with the OH ions to form ammonia
when an acid is added the ammonia will dissociate to provide OH ions which combine with the H ions to form water

Question 30

How do acidic buffers work?

Answer 30

when an alkali is added the weak acid dissociates to provide hydrogen ions which trap the added hydroxide ions and convert it to water
when an acid is added the large reserve of the ion will trap the added hydrogen and convert them back to the molecular form