Unit 2

Oxidation- distinguishes betwee two carbonyl compounds:

                  Aldehydes and Ketones

Aldehydes can be oxidised to give carboxylic acids, ketones do not oxidise.

In an oxidation reaction:

  • acidified pottassium dichromate - changes from orange to green.
  • tollen's reafent - silver mirror formed
  • benedicts solution - changes from blue to red/ orange

because of this we know that it is an aldehyde as a ketone does not react.

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PPA - oxidation

Distinguishes between two carbonyl compounds: aldehydes and ketones

Aldehydes can be oxidesed to give carboxylic acids, wheras ketones do not oxidise.

the reaction mixture contains flammable substances therfore can not be ignited by a naked flame.

oxidation reaction:-

  • acidifed potassium dichromate - changes from orange to green
  • tollens reagent - silver mirror formed
  • benedicts solution - changes from blue to red/orange

since these reactions took place we know that it is a aldehyde, as ketones do not react.

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PPA - Making Esters

labelled diagram -

  • hot water bath
  • cotton wool plug
  • wet paper towel (condensor)
  • ethanoic acid, ethanol

the reaction was catalysed by concentrated H2SO4

The condensor prevented the chemicals boiling off by cooling the vapour

sodium hydrogencarbonate was added to the products to neutralise the H2SO4 and any excess carboxylic acid.


the product had a strong smell and formed a layer over the water since esters are immiscible in water.

ethanoic acid + ethanol ---> ethyl ethanoate + water

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PPA - Factors Affecting Enzyme Activity

The effect of a pH change and a temperature change on enzyme activity. The enzyme was catalase, which catalyses the decomposition of hydrogen peroxide.

Draw diagram:-

Varying pH:

  • test tube
  • water bath with water
  • delivery tube
  • potato discks containing catalase
  • hydrogen peroxide + pH buffer, acid or alkali

Varying Temperature:

  • test tube
  • potato discs
  • hydrogen peoxide
  • thermometer
  • water bath
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PPA - Factors Affecting Enzyme Activity continued

Varying temperature:

  • beaker
  • delivery tube
  • water


the optimum pH was 7, and the optimum temperature was 39*.

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