acids and bases

Question 1

what is an acidic buffer made up of

Answer 1

• weak acid

- its salt

Question 2

What happens when an acid (H+) is added to an acidic buffer

Answer 2

• H+ reacts with dissociated acid ion(e.g ch3coo-)
• high conc. of acid ion from dissociated salt
• reforming the acid (e.g ch3cooh)
• so equilibrium shifts to the left

Question 3

What happens when a base (OH-) is added to an acidic buffer

Answer 3

• OH- reacts with H+ or dissociated salt(e.g Na+)
• however if reacts w Na NaOH formed=strong base ,strong bases dissociate completely.So OH- reacts with H+ instead formig water.

Question 4

what is a basic buffer made up of

Answer 4

• a weak base

- and its salt

Question 5

what is the method to calculating change in PH of buffer

Answer 5

1.
work out moles of acid added
work out moles of salt and acid already in buffer

2.
assume H+ from added acid w negative ion(e.g ch3coo-) and reforming the acid (e.g ch3cooh)

SO… add the moles of new acid to acid already in buffer
substract moles of