acids and bases

Question 1

acid

Answer 1

proton donor

Question 2

base

Answer 2

proton acceptor

Question 3

strong acid

Answer 3

An acid that completely dissociates to ions when in solution (0-1)

Question 4

weak acid

Answer 4

An acid that only slightly dissociates when in solution (3-5)

Question 5

strong base

Answer 5

A base that completely dissociates to ions when in solution (12-14)

Question 6

weak base

Answer 6

A base that only slightly dissociates when in solution (9-11)

Question 7

pH

Answer 7

-log10[H+]

Question 8

[H+]

Answer 8

10^-pH

Question 9

Kw

Answer 9

[H+][OH-]

Question 10

Ka

Answer 10

[H+][A-]/[HA]
10^-pKa

Question 11

pKA

Answer 11

-log10Ka

Question 12

what is a buffer

Answer 12

A solution which is able to resist changes in pH when
small volumes of acid or base are added.

Question 13

what do buffers contain

Answer 13

Acidic buffer solutions contain a weak acid and the salt of that weak acid and basic buffer
solutions contain a weak base and the salt of that weak base.

Question 14

why are buffers important

Answer 14

Buffer solutions are common in nature in order to keep systems regulated. This is important as
enzymes or reactions in living organisms often require a specific pH, which can be maintained
using a buffer solution.

Question 15

how to work out pH of a strong acid diluted with water

Answer 15

find no. moles of H+ using n=cv
find new [H+] using new total volume
use pH=-log[H+]

Question 16

how to work out pH of a weak acid

Answer 16

use [H+][A-]/[HA]
assume [H+]=[A-]
find [H+] and use pH=-log[H+]

Question 17

how to work out pH of a strong base

Answer 17

use Kw=[H+][OH-]
find [H+] and use pH=-log[H+]

Question 18

how to work out pH of a strong acid and strong base

Answer 18

calculate no. moles of H+ and OH-
find which one is in XS
find conc of the one in XS using n=cv
if H+ is in XS, use pH=-log[H+]
if OH is in XS use Kw

Question 19

how to work out pH of weak acid and salt

Answer 19

a buffer forms
find no. moles HA and A-
find conc [HA] and [A-]
use Ka=[H+][A-]/[HA] to find [H+]
find pH

Question 20

how to work out pH of a weak acid and a strong base

Answer 20

find moles of HA and OH-
find which one is in XS
find new conc [HA] using XS moles
find [A-] (mols A- =mols OH-)
use Ka expression to find [H+]
find pH

Question 21

find pH if a small amount of acid or base is added to a weak acid and salt or a weak acid and strong base

Answer 21

find no. moles of H+ or OH- added
decide which way the equilibrium moves and find the new no. moles of HA and A-
find new conc of HA and A-
use Ka expression to find [H+] and find pH