I have been given this question which just says "Describe colorimetry" for 4 marks!
All I have so far is:
Colorimetry is a method used to determine the concentration of a substance in solution.
Could anyone give me 3 more points I could write?
More specifically, a colorimeter is used to measure the change in intensity of light as it passed through a solution.
The colorimeter does this by either measuring the percentage transmission of light (ie how much light passes through a solution) or percentage absorbance( ie how much light is absorbed by a solution )
If you are asked about a colorimeter, I would probably state for 4 marks:
1) A piece of apparatus measuring a change in light intensity as it passes through a solution inside a cuvette.
2) It may record the amount of light transmitted or absorbed.
3) Light which passes through a solution passes onto a photosensitive cell and the electrical current produced is converted into a digital readout.
4) Filters must be used with a colorimeter to maximise this change in transmission or absorbance. A red or blue filter may be used depending on the final colour of the solution in the cuvette.
Note that filters may be used in experiments such as the famous amylase-starch experiment or the effect of heat on anthocyanin pigments in beetroot cell membranes.
Hope this helps a bit, any questions ask away
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