Acids & Bases

Question 1

Strong acids

Answer 1

fully ionise in solution to form H+

Question 2

Weak acids

Answer 2

partially ionise in solution to form H+

Question 3

Strong bases

Answer 3

fully dissociate to form OH- in solution

Question 4

Weak bases

Answer 4

partially reacts with water to form OH-

Question 5

Strong acids examples

3

Answer 5

• H2SO4
• HCl
• HNO3

Question 6

Weak acids examples

6

Answer 6

• CH3COOH
• H3PO4
  H2CO3
• HF
• H2S
• H2C2O4

Question 7

Strong bases examples

Answer 7

group 1 & 2 metal oxides & hydroxides

Question 8

Weak bases examples

Answer 8

NH3
metal carbonates & hydrogen carbonates

Question 9

Acid properties

taste, corrosivity, litmus, electrical conductivity

Answer 9

• sour
• corrosive
• turn blue litmus red
• can conduct electrical current

Question 10

Base properties

taste, corrosivity, litmus, electrical conductivity, feel

Answer 10

• bitter (soap)
• can be caustic
• turn red litmus blue
• can conduct electricity
• slippery feel

Question 11

acid + metal sulfite products

Answer 11

salt + water + SO2 (g)

Question 12

base + ammonium salt products

Answer 12

salt + water + ammonia gas

Question 13

base + non-metal oxide products

Answer 13

salt + water

Question 14

Concentration

Answer 14

amount of solute dissolved in a solution

Question 15

Strength

Answer 15

degree of ionisation/dissociation

Question 16

Amphiprotic

Answer 16

substance that can accept and donate a H+

Question 17

Polyprotic acid def

Answer 17

able to donate more than one proton per molecule of acid

Question 18

Why in polyprotic acids, second acid strength is weaker

Answer 18

conjugate base of OG acid has an increasingly negative charge, making it harder to donate a proton

Question 19

Electrolyte definition

Answer 19

any substance that conducts electricity when dissolved in water (present as ions in solution)

Question 20

Strong electrolytes

Answer 20

100% ionisation/dissociation
all ionic compounds & strong acids

Question 21

Weak electrolytes

Answer 21

partial ionisation
weak acids & weak bases

Question 22

Non-electrolytes

Answer 22

sucrose, ethanol

Question 23

Arrhenius def for acids & bases

Answer 23

Acids: ionise in solution to produce H+ ions

Bases: dissociate in solution to produce OH- ions

Question 24

What 2 other things did Arrhenius discover

Answer 24

• if acid & base mix the properties will become neutralised and form water
• varying strengths of acids & bases

Question 25

Limitations to Arrhenius | 3

Answer 25

- restricted to aqueous solutions only - doesn’t explain bases such as NH3 or carbonates - H+ actually reacts with water to form H3O+

Question 26

Bronsted-Lowry theory | 3

Answer 26

- acids donate a proton (H+) - bases accept a proton - write H+ as H3O + in equations!

Question 27

Humphry-Davy Theory | 3

Answer 27

- acidic properties come from H, not from oxygen as previously thought - bases are substances that reacted with acids to “neutralise” them & form a salt - H in acids could be replaced by a metal

Question 28

Humphry Davy Theory Limitation | 1

Answer 28

could not account for lack of acidic properties in some compounds containing H (CH4)

Question 29

Acidity constant (Ka)

Answer 29

numerical measure of the extent to which the proton transfer goes to completion

Question 30

HA

Answer 30

generic formula for monoprotic acid

Question 31

larger Ka | 3

Answer 31

- greater tendency to donate proton - stronger acid - stronger degree of ionisation

Question 32

conjugate base strength of large Ka | 1

Answer 32

very weak conjugate base

Question 33

What happens to conjugate base strength as Ka gets progressively weaker | 1

Answer 33

conjugate base is progressively stronger

Question 34

Neutral salts

Answer 34

conjugates of SA & SB

Question 35

Acidic salts | 3

Answer 35

- conjugates of WB (NH4+) - HSO4 - - H2PO4 -

Question 36

Basic salts | 4

Answer 36

- conjugates of WA - final line in successive ionisations - HCO3 - - HPO4 2-

Question 37

acidity of a salt created from WA + WB | 1

Answer 37

neutral salt

Question 38

What is an indicator | 2

Answer 38

chemical that changes colour depening on pH - WA/WB & it's conjugate

Question 39

Indicator equilibrium equation

Answer 39

HIn + H2O ⇌ In- + H3O+

Question 40

Buffers | 2

Answer 40

solution that resists a large change in pH upon addition of small quantity of acid/base - WA/WB & CWB/CWA

Question 41

Buffering capacity | 1

Answer 41

measure of the amount of acid/base that can be added before the buffer system experiences a large change in pH (more than 1 pH unit)

Question 42

To increase buffering capacity | 2

Answer 42

- equal concentrations of WA/WB & it's conjugate - increase [WA/WB] & [CWB/CWA]

Question 43

Producing a buffer | 2

Answer 43

- 1:1 ratio of WA/WB & CWB/CWA - 2:1 ratio of WA/WB & SB/SA

Question 44

Collision Theory buffers | 3

Answer 44

- what in buffer system reacts with H3O+/OH- & equation showing that - how that effects [] of og buffer system, further effects rate of collisions & reaction rate - at a new equilibrium, most of the added H3O+/OH- has been consumed, so only slight increase/decrease in pH

Question 45

LCP buffers | 4

Answer 45

- when small amounts of acid/base are added, how that affects [H+/OH-] in buffer system - to oppose this change, equilibrium shifts - how that affects concentration of system - **[OH-/H+] increases/decreases only slightly higher/lower than before addition of acid/base, so only slight increase/decrease in pH**

Question 46

H2CO3/HCO3- buffer equation

Answer 46

H2CO3(aq) + H2O(l) ⇌ H3O+(aq) + HCO3-(aq)