UNIT 3 Section 5 - Isomerism and Carbonyl Compounds Flashcards
what is optical isomerism
a type of stereoisomerism where atoms are arranged differently in space and have a chiral carbon
what is a chiral carbon
a carbon atom with four different groups attached to it
what are enantiomers
are mirror images and no matter how you rotate them they cannot be superimposed and are therefore chiral
what is plane polarized light and how do you create it
when normal light is passed through a polarizing filter is becomes plane polarised lights which is when all the light it is vibrating in the same plane
what is a racemate
are they optically active?
A racemate contains equal quantities of each enantiomer of an optically active compound and they do not show optical activity as the two enantiomers cancel each other out
how can you test for aldehydes
Tollens reagent: add tollens reagent and heat it. If there is an aldehyde a silver mirror on the test tube will form
OR
Fehling’s solution :A blue solution made of copper ii ions dissolved in sodium hydroxide and if it is heated with an aldehyde the sopper ii ions are reduced to rick red precipitate of copper I oxide
what is the name of the reducing agent used to reduce ketones and aldehydes
sodium tetrahybridoborate III
what is the general equation of the reaction of acids and carbonates
Acid + carbonate —> water + carbon dioxide + salt
what is the appearance of the reaction between an acid and a carbonate
effervescence of CO2
what is the general equation for esterification and what are the conditions
Carboxylic acid + alcohol —-> Ester + water
acid catalyst
what are the conditions for esterification
an acid catalyst of either concentrated sulfuric acid , HCL and H3PO4
what are the 3 uses of esters and why are they good for the use
- perfumes due to their sweet smells
- glues and printing ink due to the fact they are polar
- plasticisers to make plastics more flexible
what are the two types of hydrolysis of esters and what are the conditions of each
acid- reflux of the ester with a dilute acid like HCL or H2SO4
base- reflux the ester with a dilute alkali such as NaOH and
explain why fats are solid at room temp and why oils are liquid
fats are solid as they have hydrocarbon chains fitting neatly together increasing the van der waals between them and therefore a higher melting point
oils have unsaturated hydrocarbon chains and the double bonds cause the chains to bend and therefore decrease the van der waals and have a lower melting point
what are the reactants and conditions of making biofuel
oils + methanol in the presence of a strong alkali as a catalyst
what can acyl chlorides react with
water, alcohols, ammonia and primary amines
what are the observations of acyl chlorides reacting with nucleophiles and why does it happen
- colourless fuming gas
- strong smalling of vinegar due to hydrogen chloride gas
this is due to the acyl chloride reacting with water vapour in the air because they are so reactive
how is aspirin manufactured
salicylic acid + ethanoic anhydride/ethanoyl chloride
what are the reasons why ethanoic anhydride is used industrially instead of acyl chlorides
it is cheaper than ethanoyl chloride a
also safer as it is less corrosive
reacts more slowly with water so doesn’t produce the dangerous hydrogen chloride fumes
how do you hydrolyse oils and fats
what are the products of the reaction
heating them with sodium hydroxide and this is base hydrolysis.
The alcohol formed it a glycerol when the OH- ions react with the oil/fat and the carboxylate ions combine with Na+ ions from the NaOH to form a sodium salt(soap)
