Introduction to Organic Chemistry
5 marks · EasyEthanol and ethene are two different organic compounds.
Name the type of formula shown here for ethanol: CH3CH2OH
Which functional group is present in ethanol and how does it affect its chemical properties?
Write the displayed formula for ethene.
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(a) condensed structural (or structural) formula
(b) Ethanol contains the –OH (hydroxyl) functional group. This makes it an alcohol and gives it its typical chemical properties, such as being able to react with sodium and oxidise to form acids.
(c) — · must show C=C double bond, 2 carbon atoms, 4 hydrogen atoms, all bonds shown
Common mistakes: Confusing displayed and structural formulae; Stating 'alcohol group' rather than –OH
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States 'structural' or 'condensed structural formula'.
B1 (b) · 1 mark · Correctly states or describes the functional group in ethanol is –OH (hydroxyl).
B1 (b) · 1 mark · Describes an effect of the –OH group on chemical properties (e.g. makes it an alcohol, allows it to react with sodium, oxidise, etc.).
B1 (c) · 2 marks · Displayed formula: C=C double bond between two carbons, correct total number of H atoms and bonds. 1 mark for correct backbone, 1 mark for all bonds shown.
Worked solution
a) The formula CH3CH2OH is a condensed structural (or simply structural) formula.
b) Ethanol contains the –OH (hydroxyl) functional group. This makes ethanol an alcohol and means it has characteristic reactions, like reacting with sodium and oxidising to acids.
c) Displayed formula for ethene:
Show two carbon atoms with a double bond between them. Each carbon is bonded to two hydrogen atoms. All bonds should be shown clearly.