acids, bases and buffers

Question 1

what is a Bronsted-Lowry acid

Answer 1

proton donor

Question 2

what is a Bronsted-Lowry base

Answer 2

proton acceptor

Question 3

write the equation for the ionisation of water

Question 4

give an example of a monobasic acid

Answer 4

HCl

Question 5

Give an example of a dibasic acid

Answer 5

H2So4

Question 6

give an example of a tribasic acid

Answer 6

H3PO4

Question 7

write the acid dissociation constant expression

Question 8

what does a larger Ka value mean

Answer 8

greater extent of dissociation

Question 9

what is the relationship between pKa and strength of the acid

Answer 9

smaller the pKa value the stronger the acid

Question 10

why is a pH scale useful compared to conc of H+

Answer 10

allows a wide range of H+ conc to be expressed as simple positive values

Question 11

[H+] of a strong acid is equal to what

Answer 11

HA

Question 12

equation for calculating [H+] of weak acids

Answer 12

square root of Ka x [HA]

Question 13

what is the assumption made when calculation the pH of weak acids

Answer 13

that the conc of acid at equilibrium is equal to the conc of acid after dissociation, this because only very little of the acid dissociates

Question 14

write expression for ionic product of water

Answer 14

Kw=[H+][OH-]

Question 15

what are the units for Kw

Answer 15

mol2dm-6

Question 16

what factors affect Kw

Answer 16

temperature
if increased equilibrium moves right so Kw increases and pH of water decreases

Question 17

equation for calculating [H+] of strong bases

Answer 17

Kw/Oh-

Question 18

define a buffer solution

Answer 18

a mixture that minimises pH change when small amount of an acid or base are added

Question 19

wat are the two ways buffers can be made

Answer 19

weak acid and its conjugate base
weak acid and a strong alkali

Question 20

which way does equilibrium shift when an acid is added to a buffer solution and why

Answer 20

shifts left
[H+] increases
conjugate base reacts its with the H+ to remove it

Question 21

which way does equilibrium shift when an alkali is added to a buffer solution

Answer 21

shifts to the right
oH- increases
small conc of [H+] reacts with OH-
to restore H+ ions HA dissociates shifting the equilibrium

Question 22

which buffer solution maintains blood pH at 7.4, what happens when acid/alkali is added?

Answer 22

physcicsandmathstutor flashcard no93

Question 23

draw titration curve for a strong bas titrated with strong base

Answer 23

physicsandmathstutor 99

Question 24

draw the titration curve for a weak acid with a strong base added

Answer 24

physicsnadmatshtuto 101

Question 25

draw titration for strong acid with weak base

Answer 25

physcisandmatshtutor 103

Question 26

draw titration curve for weak acid and weak base

Answer 26

physcisandmathstutor 105

Question 27

what us the end point

Answer 27

the point at which pH changes rapidly