Topic 2: Alcohols, Acids, Esters, soaps and emulsifiers Flashcards
an alcohol is a molecule containing what functional group
hydroxyl (-OH)
whats indicated in the name of an alcohol
the position of the hydroxyl group and the number of carbons
what can alcohols be classed as when the hydroxyl group is on a terminal carbon
primary
what can alcohols be classed as when the hydroxyl group is on a central carbon
secondary
what can alcohols be classed as when the hydroxyl group is on a central carbon that also has a branch
tertiary
what are alcohols containing two hydroxyl groups called
diols
what are alcohols containing three hydroxyl groups called
triols
hydroxyl groups make alcohols _______, due to the differences in electronegativity of the O and H atoms, and this gives a rise to ______ ______ between molecules
polar, hydrogen bonding
carboxylic acids are molecules containing the what functional group
carboxyl, (-COOH)
ask if it has the H or not
metal oxide + carboxylic acid =
salt + water
metal hydrooxide + carboxylic acid =
salt + water
metal carbonate + carboxylic acid =
salt + water + carbon dioxide
the name of a carboxylic acid with 2 carbons
ethanoic acid
an ester us a molecule containing the ester link…
-COO, first O is double bonded
ask if it has the H or not
esters can be named from the names of their parent alcohol and carboxylic acid
___ from the alcohol and ____ from the acid
-ly from alcohol
-oate from acid
uses of esters
flavourings and fragrances as many have a pleasant fruity smells
how are esters formed
by a condensation reaction between an alcohol and a carboxylic acid
what is the small molecule eliminated in a condensation reaction
water
esters can be hydrolysed to produce…
an alcohol and carboxylic acid
the condensation of what creates edible fats and oils
glycerol and 3 carboxylic acid molecules
the carboxylic acids contain long chains of carbon atoms known as…
fatty acids
whet do the double bonds in fatty acids prevent
oil molecules from packing too closely together
the more double bonded C-C present in a fatty acid the stronger or weaker the Van der Waals forces of attraction
weaker
the greater the degree of unsaturation, the _______ the melting point
lower,
so edible oils have a lower melting point than edible fats
roles of fats and oils
-concentrated energy source
-essential for the transport and storage of fat soluble vitamins in the body
soaps are produced by the ____ _____ of edible fats and edible oils
alkaline hydrolosis
Hydrolosis produces 3 ______ and 1 _______
fatty acid molecules, glycerol molecule
when fatty acid molecules are neutralised by the alkali what do they form
water-soluble, ionic salts called soaps
what can soaps be used to remove (2)
non polar substances such as oil and grease
describe the tail of a soap ion
soap ions have long non-polar tails, which are soluable in non-polar compounds (hydrophobic)
describe the headof a soap ion
soap ions have an ionic head that is water soluble (hydrohilic)
what is hard water
water that contains high levels of dissolved metal ions such especially Mg²⁺ and Ca²⁺
what happens when soap is used in hard water
an insoluble precipitate is formed called scum
what happens when a detergent is used in hard water
no scum is formed
what are emulsifiers used for
prevents the non-polar and polar liquids separating into layers
