2017 ppq Flashcards
Explain how a line is produced in an emission spectrum
Electrons promoted/excited
Falls/moves/jumps to lower level
energy/photon(s)/light is emitted/ released
Explain why there is a series of lines at discrete wavelengths in the emission spectrum of cadmium.
Different energy levels/subshells
Explain why Cu2+(aq) can be described as a homogeneous catalyst in this reaction.
It is in the same state as the ions in the reaction
State what is meant by a dative covalent bond.
Both electrons come from the same atom
Zinc ethanoate can be prepared from zinc hydroxide and ethanoic acid.
Name this type of reaction.
Neutralisation
State what is meant by a weak acid.
Partially dissociated (into ions) in solution/water/aq
Name the piece of apparatus that should be used to store the zinc ethanoate while cooling.
Dessicator
Outline the steps that should be carried out to recrystallise phenolphthalein.
minimum/small (volume) hot solvent/hot ethanol/hot ethanol (aq) filter (to remove impurities) cool
Name a technique that could be used to determine if the recrystallised phenolphthalein is pure.
Melting point/mixed melting point
Suggest, with reference to the structures, how 1H NMR spectroscopy could be used to distinguish between glucose and fructose.
Different numbers of peaks/ proton/hydrogen environments
Suggest how the functional groups circled on the Relenza molecule would bind with part of the enzyme active site.
hydrogen bonding
The concentration of hydrogen peroxide determined by the student was less than the concentration stated on the label for the stain remover.
One possible source of error could be an inaccurate concentration of the permanganate solution.
Describe how the student would confirm the concentration of the permanganate solution.
Titrate with (named) standard solution/solution of known concentration
Suggest why an ether could be a suitable solvent to extract trimyristin oil from nutmeg.
similar polarities
Suggest why the mixture was heated under reflux.
to prevent vapours escaping
