Acid Base Buffers

Question 1

Definition of a weak acid

Answer 1

Partially dissociates in water

Question 2

Give two examples of weak acids

Answer 2

CH3COOH, H2CO3

Question 3

What is the expression for equilibrium constant (Ka) ?

Answer 3

KA = (H+)(A-)/(HA)

Question 4

What does a high Ka value mean ?

Answer 4

Stringer acid , more dissociated

Question 5

Formula to find PKa

Answer 5

-log(Ka)

Question 6

How to find PH (equation )

Answer 6

-log(H+)

Question 7

Equation to find conc H+ ions

Answer 7

10-PH

Question 8

KW equation

Answer 8

Kw= (H+)(OH-)

Question 9

When would you usually use Ka?

Answer 9

When working with weak acids

Question 10

When would you usually use Kw?

Answer 10

Strong base reactions or neutralisations

Question 11

Explain what happens when an acid is added to an acidic buffer solution

Answer 11

Equilibrium shifts to the left to reduce the H+ ion concentration on the right hand side (shifts to the side of the acid)

Question 12

Explain what happens to an acidic buffer solution when a base is added

Answer 12

Conc of OH ions increases and react with H* ions to form water. Equilibrium shifts to the right to replace lost H+ ions