acids and bases

Question 1

strong acids definition

Answer 1

strong acids disassociate fully in aqueous solution

Question 2

monoprotic strong acids equation

Answer 2

HCL -> H+ + CL-

HNO3 -> H+ + NO3-

Question 3

Diprotic strong acids equation

Answer 3

H2SO4 -> 2H+ SO42-

Question 4

HCL + H2O

Answer 4

HCL + H2O -> CL- + H3O+
H3O+ - is a hydronium ion formed by a coordinate bond (pyramidal)

Question 5

weak acid definition

Answer 5

weak acids partially disassociate in aqueous solution

Question 6

monoprotic weak acid equation

Answer 6

CH3OOH <=> CH3COO- + H+

Question 7

What is a bronsted- lowry acid

Answer 7

a proton donor

Question 8

strong base definition

Answer 8

strong bases fully dissociate in an aqueous solution

Question 9

monobasic equation

Answer 9

NaOH -> Na+ + OH-

Question 10

Dibasic equation

Answer 10

Ba(OH)2 -> Ba2+ + 2OH-

Question 11

weak bases definition

Answer 11

weak bases partially dissociated in aqueous solution

Question 12

monobasic weak base

Answer 12

NH3 + H2O <=> NH4+ + OH-

Question 13

A Bronsted lowrey base

Answer 13

is a proton acceptor

Question 14

acid / base pairs
CH3COOH + H2O

Answer 14

CH3COOH + H2O <=> CH3COO- + H3O+
acid + base <=> conjugate base of CH3COOH + conjugate acid of water

Question 15

what is the pH scale

Answer 15

measure of the acidity of a solution

Question 16

pH equation

Answer 16

pH = -log10 [H+]

all pH values must be given to 2.d.p

Question 17

the reverse of the pH equation

Answer 17

[H+] = 10-pH

Question 18

what is the pH of water at 298 kelvins

Answer 18

7

Question 19

increasing temperature of water

Answer 19

H2O <=> H+ + OH-
if we increase temp it will shift equilibrium to decrease the temperature by favouring the forward, endothermic reaction. therefore at a higher temp [H+] increases

Question 20

what is Kw

Answer 20

ionic product of water

Question 21

Kw equation

Answer 21

Kw = [H+] [OH-]

units must be: mol2dm-6

Question 22

what does Kw link

Answer 22

links [H+] to [OH-] to allow us to find the pH of alkalis (provided we know that the temperature is constant)

Question 23

what happens when water is added to a solution

Answer 23

the conc will decrease, the volume will increase, and the number of moles are unaffected

Question 24

dilution equation

Answer 24

C1 V1 = C2 V2

Question 25

describe the pH of weak acids

Answer 25

weak acids partially dissociate in solution, meaning [H+] is not equal to the conc. of the acid itself

Question 26

ka equation

Answer 26

Ka = [H+] [A-] / [HA]

Ka = should be a small number

Question 27

pH curves features

Answer 27

• x axis - volume of alkali added/ cm3
• y axis - pH
• equivalence point (moles of alkali= moles of acid used)
• buffer region (weak-acid, strong acid-weak base)

Question 28

features of phenolphthalein

Answer 28

• colourless -> pink
• pH 8.3-10.0
• would use with any strong alkali

Question 29

features of methyl orange

Answer 29

• red -> yellow
• pH 3.1- 4.4
• would use with any strong acid

Question 30

formula for pKa

Answer 30

pKa = -log10 Ka
Ka = 10-pKa

Question 31

what does a lower value of pKa show

Answer 31

higher value of Ka

Question 32

what does a higher value of Ka show

Answer 32

more disassociation of the weak acid