5.1.3- Acids, Bases and Buffers

Question 0

Define Brønsted-Lowry base

Answer 0

Proton (H+ acceptor)

Question 1

Define Brønsted-Lowry acid

Answer 1

proton (H+) donor

Question 2

Acid plus metal goes to…

Answer 2

Salt plus hydrogen

Question 3

Acid plus carbonate goes to…

Answer 3

Salt plus water plus carbon dioxide

Question 4

Acid plus base goes to…

Answer 4

Salt plus water

Question 5

Acid plus alkali goes to…

Answer 5

Salt plus water

Question 6

Define a neutralisation reaction

Answer 6

A chemical reaction in which an acid and a base react together to produce a salt and water

Question 7

Define a conjugate acid-base pair

Answer 7

Two species that transform into each other by gain or loss of a proton

Question 8

Define a conjugate acid

Answer 8

A species formed when a proton is added to a base

Question 9

Define a conjugate base

Answer 9

A species formed when a proton is taken from an acid

Question 10

What is the formula of the hydronium ion

Answer 10

H3O+

Question 11

Define a strong acid

Answer 11

An acid that completely dissociates in solution

Question 12

Define a week acid

Answer 12

And acid that partially dissociates in solution

Question 13

What is the acid dissociation constant

Answer 13

It shows you the extent of acid dissociation

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

Question 14

Define pH

Answer 14

pH= -log[H+]

Question 15

What does [H+] mean and equal

Answer 15

The concentration of H plus ions

[H+]=10^-pH

Question 16

What is the Ionic product of water (Kw)

Answer 16

Kw = [H+][OH-] = 1.00 x 10-14 mol2dm-6 at 298K

Question 17

Define a buffer solution

Answer 17

A system that minimises pH changes in addition of small amounts of acid or base

Question 18

What makes a buffer solution

Answer 18

A weak acid and its conjugate base. For example you can mix a weak acid with a salt of the weak acid eg. CH3COOH/CH3COONa

Question 19

How does a buffer solution reduce pH changes on the addition of acid (H+)

Answer 19

1. [H+] is increased
2. The conjugate base A- reacts with the H+
3. The equilibrium shifts left removing most of the added H+

Question 20

How does a buffer solution reduce pH changes on the addition of base (OH-)

Answer 20

1. [OH-] is increased
2. The H+ ions react with the OH-
3. The weak acid HA dissociates to replace most of the H+ that reacted.

Question 21

Name the buffer solution that controls blood pH

Answer 21

Carbonic acid - hydrogencarbonate buffer solution (H2CO3 - HCO3-)

Question 22

What pH range should blood be kept to

Answer 22

7.35-7.45

Question 23

Define the equivalence point

Answer 23

The point in a titration at which the volume of one solution has reacted entirely with the volume of the second solution

Question 24

Define the end point

Answer 24

The endpoint of an indicator is the point in the titration at which there are equal concentrations of the week acid and conjugate base forms of the indicator.

Question 25

Define the standard enthalpy change of neutralisation

Answer 25

The Energy change that accompanies the neutralisation of an aqueous acid by an aqueous base to form one mole of H2O under standard conditions