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level: Esters, fats and oils

Questions and Answers List

level questions: Esters, fats and oils

QuestionAnswer
what is the functional group of an esterester link -COO-
how is an ester formedwhen a carboxylic acid molecule reacts with an alcohol molecule in a condensation (esterification) reaction
what is the catalyst for an esterification reactionconcentrated sulphuric acid
what ester is formed when you react ethanol and propanoic acidethyl propanoate
what ester is formed when you react butanoic acid and ethanolethyl butanoate
what are the uses of estersartificial flavourings perfumes solvents for non polar solutes
what is a condensation reactionwhen two molecules are joined with the elimination of a small molecule - water
what do you get when you react an alcohol and a carboxylic acidan ester and water
what is the functional group of an esterester linkage -COO-
how is the rate of an esterification reaction increasedby heating the reaction mixture and using concentrated sulphuric acid as a catalyst.
are esterification reactions reversibleyes
how do you draw an esterthe H from the alcohol and the OH from the carboxylic acid form water replace these with the ester linkage
how do you make esters in a labequal quantities of the reactants (alcohol and carboxylic acid) are added to a test tube concentrated sulphuric acid is added as a catalyst a wet paper towel is put around the top of the test tube to act as a condenser the tube is placed into a beaker of hot water/water bath reaction mixture is poured onto sodium hydrogen carbonate solution to neutralise the concentrated sulphuric acid and any unreacted carboxylic acid
what is evidence that an ester has formed when making them in a labthere is a distinct smell two layers are formed
why are bunsen burners not used when making esters in the labalcohols are flammable
are esters polar or non polarnon polar
what is hydrolysislarge molecules are broken down into smaller molecules by reaction with water it is the opposite to condensation
what do you get upon reacting propyl methanoate with waterpropanol methanoic acid
what bond on the ester is broken during hydrolysis...
what types of hydrolysis are reversibleacid catalysed hydrolysis is reversible alkali catalysed hydrolysis is not
how do you carry out the hydrolysis of esters in a labthey are heated under reflux: heating the mixture with a condenser attached this ensures that volatile compounds do not escape and allows the reaction to take place at a higher temperature
what is the role of fats and oils in our dietsthe provide us with energy they are essential for the transport of fat soluble vitamins
what is the difference between fats and oilsfats are solids and oils are liquids
are fats and oils soluble in waterno
describe the volatility of fats and oilsthey are very volatile as they are esters
how are edible fats and oils formedas they are esters they are formed from the condensation reaction of glycerol with three fatty acid molecules (carboxylic acids) each molecule of the alcohol condenses with 3 molecules of fatty acid (R1, R2,k R3 are long carbon chains which can be the same or different)
what is another name for glycerolpropane-1,2,3-triol
how many OH groups does glycerol havethree therefore it can form three ester links with fatty acid molecules to form a triglyceride
what are fatty acid moleculessaturated or unsaturated straight chain carboxylic acids with usually long chains of carbon atoms. They contain an even number of carbon atoms
what kind of fatty acids do fats tend to be formed fromsaturated fatty acids
what kind of fatty acids do oils tend to be formed fromunsaturated fatty acids
is there a higher degree of unsaturation in oils or fatsin oils
describe the structure of fatsfats are saturated which means more efficient packing and therefore stronger van der waals interactions because of this fats have a higher melting point than oils and more energy is required to separate the molecules, so they are solids
describe the structure of oilsoils are unsaturated meaning they will have a distorted structure that can't pack as closely and weaker van der waals interactions.. lower melting point than fats, less energy required to separate molecules, so are liquids.
what happens during an addition reaction of bromine reacting with unsaturated compoundsbromine molecules add across the carbon-carbon double bond the greater the number of double bonds of a substance, the more bromine solution can be decolourised
what happens when an oil is shaken with bromine waterthe brown colour of bromine water is decolourised this indicates the presence of double bonds in the oil molecules
what happens when a fat is dissolved in an organic solvent and then shaken with bromine waterno decolourisation occurs with some fats and onlhy slight or slow decolourisation with others this indicates that fats may contain no double bonds or fewer double bonds than oils
what is meant by monounsaturatedonly one carbon to carbon double bond
what is meant by polyunsaturatedmore than one carbon to carbon double bond