Organic Reactions Flashcards
What do all organic molecules contain
Carbon atoms
What are functional groups
Double carbon bonds
Alcohol groups
Carboxylic acid groups
Esters
What is the family of organic compounds with the same functional group called
Homologous series
How does the homologous series differ
By an extra carbon atom that has 2 hydrogen atoms bonded to it
Combustion of alkenes
Test ethene gas with lighted spill
Burn with yellow flame
Release less energy
Addition reactions of alkenes
C=C
Double bond
More reactive than alkanes
Alkenes reaction with halogens
Test ethene with bromine water
Orange to colourless
Reaction with hydrogen
Do not contain maximum number of hydrogen atoms possible in hydrocarbon molecule
Reaction gets rid of double bond
Straightens molecules and increase melting points
Reaction with steam
Ethanol = made from ethene gas
ethene + steam <=> ethanol
reversible
The three homologous series
Alcohols, carboxylic acids, esters
Alcohols
Removing H atom from alkane molecule by replacing it with -OH group
-OH functional group
Formula = C2H6O
Carboxylic acids
-COOH functional group
Esters
Closely related to carboxylic acids
Replace H atom
-COO- functional group
Structural formula of ethyl ethanoate = CH3COOCH2CH3
Uses of alcohols
Fermenting sugars from plant material with yeast
Biofuel
Ethanol can be made with ethene and steam using a catalyst
Non-renewable source
Alcohols dissolve many of same substance as water
Smaller molecules mix well with water = neutral solutions
Dissolve other organic compounds
Combustion with alcohols
Fuels Flammable Biofuel in cars Blue flame Ethanol + oxygen -> carbon dioxide + water
Reaction with sodium
Produces H2
Gets smaller and smaller as it forms solution of sodium ethoxide in ethanol
Oxidation
Combustion is one way to oxidise alcohol
Alcohol is oxidised to carboxylic acid when boiled with acidified potassium dichromate solution
Ethanol + oxygen atoms from oxidising agent -> ethanoic acid + water
Tests for ethanoic acid
1) take pH
2) add potassium carbonate to acid
3) add magnesium ribbon to acid
4) test conductivity using simple circuit of cell, 2 carbon electrodes and bulb
5) collect gas given off from negative electrode with lighted spill
Why are carboxylic acids called weak acids
CO2 given off slowly when metal carbonate reacts with carboxylic acid
Carboxylic acids = weak acids
Strong acids ionise complete and weak acids dont
Reversible reaction takes place
Making esters
Carboxylic acid + alcohol ->(acid catalyst)-> ester + water
