EXAM QS

Question 1

is the experimental method valid?

2019 VCAA 5b

Answer 1

• The method is valid as data is consistent for standard solutions of different concentrations
  made up from pure sucrose.
• The conditions used in the HPLC were consistent across all the standards and the soft drink
  solution.
• Peak areas for the standard solutions and the diluted soft drink sample were recorded at the
  same retention time (of sucrose).
• The method is invalid because not enough points were established from zero glucose through
  to 0.80 g L–1 glucose.

Question 2

fators that would limit the life of the zinc-cerium cell

VCAA 2018 7f

Answer 2

loss/breakdown/oxidation/corrosion of the Zn electrode
* side reactions at the electrodes
* electrolysis of water during recharging
* (-) 2H+
(aq) + 2e– → H2(g) ; (+) 2H2O(l) → O2(g) + 4H+
(aq) + 4e–
* significant temperature change
* build-up of gases around electrode.

Question 3

which chemical analysis is most useful in determining whether a compound has a stereoisomer

VCAA 2019 MCQ12

Answer 3

NMR - peak area and splitting patterns are diff

misconception - chose infrared bc uv light causes clockwise /anticlockwise BUT infrared is infrared radiation

Question 4

one factor that would limit life of ZINC cerium cell

2019 VCAA Q7f

Answer 4

• corrosion of ZN electrode
• side reactions at electrode

Question 5

safety risk w chemical in experiment

2019 VCAA 9bi

Answer 5

• products that form
• hydrogen gas is flammable
• ensure no ignition sources are present

Question 6

state change to experimental design do they can achieve their aim of measuring current efficiency

2019 VCAA 9G

Answer 6

• use higher or borader range of NaCl
• hi8gher conc most likely to prouce chlrine gas
• 2 diff oxidation reactions occurring

Question 7

aspects of electrolysis experiment included in discussion section

2019 VCAA 9h

Answer 7

whether the data supports or refutes the aim/hypothesis
* comparison of expected to actual results
* analysis experimental design and errors
* relating to earlier work/theory (e.g. electrochemical series and its use in predicting electrode
half-equations).

Question 8

potential safety hazards of MG-NA hybrid cell

2021 vcaa 2b

Answer 8

• battery may overheat
• Mg relatively reactive so may react in body
• leakage of products/reactants

Question 9

amylose and cellulose similarities and differences in structure

2021 vcaa 3e

Answer 9

• glucose monomers
• straight chain unbranched polmers
• glycosidic links
• difference: CH2Oh group in amulose remains on same side of polymer
• in cellulose it alternates
• alpha glucose for amylose and beta glucose for cellulose