5.1.3 Buffers and Neutralisation

Question 1

buffer solution

Answer 1

a system that minimises pH changes when small amounts of acid or a base are added

Question 2

what 2 components does buffer solution contain

Answer 2

weak acid
conjugate base

Question 3

what does the weak acid in a buffer solution remove

Answer 3

added alkali

Question 4

what does the conjugate base in a buffer solution remove

Answer 4

added acid

Question 5

does the pH change as the buffer works

Answer 5

yes it doesnt remain completely constant

Question 6

what happens if you add acid to a buffer

Answer 6

[H+] increases
H+ react with conjugate base A-
equilibrium position shifts left to remove most H+ ions

Question 7

what happens to buffer if you add a alkali

Answer 7

[OH-] increases
H+ react with OH- to form water
HA dissociates shifting equilibrium position to the right to restor the [H+]

Question 8

whats true when [HA]=[A-]

Answer 8

pH of buffer is same as pKa value of HA
operating pH is over about 2 pH units centred at pH of the pKa

Question 9

Ka=

Answer 9

[H+][A-] / [HA]

Question 10

equation to work out [H+] of buffer

Answer 10

Ka x [HA] / [A-]

Question 11

what is the pH range of blood

Answer 11

7.35 - 7.45

Question 12

how to find equivilance point

Answer 12

centre of the vertical point of the pH titration curve

Question 13

what is the equivilance point

Answer 13

the volume of one solution that exactly reacts with volume of other solution

Question 14

what colour is a weak acid in methyl orange

Answer 14

red

Question 15

what is the colour of a conjugate base in methyl orange

Answer 15

yellow

Question 16

what is the end point of an reaction

Answer 16

when the concentration of HA and A- are equal