Topic
Suggestions
Advice
Allocated to:
Enzyme kinetics
ONE
Catalase (yeast/potato) 2H2O2 > 2H2O + O2
Three variables from: concentration (enzyme and substrate); temperature; pH; inhibition; compared with inorganic catalysts. These experiments are easy to do, especially catalase, but are lengthy and difficult to maintain over several weeks. Check the solutions, each day, by running a standard experiment. Doug

Olivier

Enzyme kinetics
TWO
Amylase on starch substrate
AS ABOVE  
Clock reaction
ONE
Iodine (hydrogen peroxide)
H2O2 + 2I- + 2H+ > I2 + 2H2O
Three variables eg concentrations of each reactant, and temperature. Analysis section to include order, rate equation and activation energy  - same general ideas as "Clock two"
Manahil

Becky
Clock reaction
TWO
Iodine (peroxodisulphate)
S208- + 2I- > 2S042- + I2
Top investigations discuss mechanisms and try to find a catalyst and its activation energy  - same general ideas as "Clock one" Zahra

Eleanor

Clock reaction
THREE
Bromine (bromate(v))
5Br- + BrO3- + 6H+ > 3Br2 + 3H2O
Again, always check your solutions, each day, by running a standard experiment. Easy experiments to do and repeat - same general ideas as "Clock one" Ellie

Claire

Aspirin
Titration (acid-base)
Colorimeter
Back titration
pH titration
Analysis should find the percentage of salicylic acid in the sample. Compare the different methods. Don't use melting points or thin layer chromatography as methods!
 
Bleach
lodine/thiosulphate titration
Volume of oxygen
Thermometric titration
A popular choice but rarely done well. Need sodium chlorate(I)(aq) of known concentration. Compare methods and then try commercial bleaches. Luke

Sak

[Cu2+]
Thiosulphate titration
Colorimeter
EDTA titration
lon-exchange
Gravimetric
Recommend three methods to compare, using a known concentration (analar copper sulphate crystals). Then try an unknown concentration. With its variety of methods this should become more popular - CAN BE VERY DIFFICULT so only do it if you really don't like any of the others (or if you enjoy making life difficult for yourself) Louise

no one else

Kinetics
ONE
Propanone / I2
Need at least three variables. Analysis section to include order, rate equation and activation energy.
 
Kinetics
TWO
Manganate(VII) / C2O42- AS ABOVE  
Kinetics
THREE
Thiosulphate / H+ AS ABOVE  
NOTE: There is significant emphasis in the assessment descriptors on planning and evaluating, and on the evidence collected being accurate and reliable. It is vital, therefore, for students to review critically each set of data as soon as it has been collected to decide whether further experiments are required. Students should concentrate on the quality, rather than the quantity, of the evidence gathered. Any aspect of chemistry can be investigated, but will only be classified as a "good" investigation if it has enough scope and produces enough data.