Acid-Base Equilibria

Question 1

How do strong acids dissociate

Answer 1

Fully, to release the same number of moles of H+ ions and conjugate bases

Question 2

How do weak acids dissociate

Answer 2

Partially, and release far fewer moles of H+ ions as conjugate base

Question 3

How do you calculate pH

Answer 3

-log[H+]

Question 4

How do you calculate [H+]

Answer 4

10^-pH

Question 5

How do you calculate the acid dissociation constant

Answer 5

the concentration of the products multiplied by the concentration of the acid

Question 6

How do you calculate the pH of a strong base

Answer 6

The [H+] is equal to 1x10-14 over the OH- conc

Question 7

What is an indicator

Answer 7

A weak acid that changes colour at a particular pH

Question 8

How is pKa calculated

Answer 8

-log(Ka

Question 9

Describe the titration curve with a strong acid and base

Answer 9

Almost no increase and then a sudden increase

Question 10

Describe the titration curve with a strong acid and weak base

Answer 10

A buffering curve followed by a sharp increase with an equivalence point below 7

Question 11

Describe the titration curve with a strong base and a weak acid

Answer 11

A buffering curve followed by a sharp increase with an equivalence point above 7

Question 12

How do you calculate the pH of a buffer

Answer 12

[H+] = Ka x [acid]/[base]

Question 13

How do you calculate the change in pH of a buffer

Answer 13

Calculate the concentration of the change, eg 1 mol HCl in 1000dm. If an acid, add to the conc of acid and subtract from conc of base or vice versa. Then use buffer pH equation as normal