Mod 6: Acid/Base Reactions

Question 1

Arrhenius theory

Answer 1

Acids produce H+ and bases produce OH- in aqueous solution

Question 2

Arrhenius improvements

Answer 2

Accounts for the relative strength between different acids

Question 3

Arrhenius limitations

Answer 3

Acid base reactions do not always occur in solution e.g. HCl(g) + NH3(g) -> NH4Cl(s)

Question 4

Bronsted-Lowry theory

Answer 4

Acid is a proton donor, a base is a proton acceptor

Question 5

Bronsted-Lowry improvements

Answer 5

Accounts for acids and bases in gasesous state

Question 6

Bronsted-Lowry limitations

Answer 6

Cannot explain reactions between acidic and basic oxides e.g. CaO(s) + SO3(g) -> CaSO4(s)

Question 7

Indicator for strong acid and strong base (include pH)

Answer 7

Bromothymol blue (6-7.6)

Question 8

Indicator for strong acid and weak base (include pH)

Answer 8

Methyl orange (3.1-4.4)

Question 9

Indicator for weak acid and strong base (include pH)

Answer 9

Phenolphthalein (8.3-10)`

Question 10

Properties of a good solute for a primary standard

Answer 10

Highly pure, stable (not hydroscopic - reacting with water in air), highly soluble in water, large molecular weight (reduce error in weighing)

Question 11

Equivalence point

Answer 11

When in stoichiometric ratio

Question 12

Endpoint

Answer 12

When indicator changes colour

Question 13

Aliquot

Answer 13

Accurately known volume of solution delivered by pipette

Question 14

Titrant

Answer 14

Solution of known concentration

Question 15

Titre

Answer 15

Total volume of solution delivered by the burette

Question 16

Concordant titres

Answer 16

Volume of 3+ titres are within 0.05mL

Question 17

Use of acid/base by Aboriginal and Torres Strait Islander peoples

Answer 17

Quandong fruit = Contains 2x the vitamin C of an orange

Question 18

Buffers in natural systems

Answer 18

CO2 is a product of cellular respiration, absorbed by blood CO2 + H2O H2CO3 forming carbonic acid. This forms H2CO3 + H2O HCO3- + H3O+ hydrogen carbonate (bicarbonate) as when H+ is added, shifts EQ left, but when OH- added it neutralises the H+ removing it and shifting EQ right