C10 Flashcards
what is a functional group
eg c=c grouping
gives a ‘family’ of organic compounds their characteristic reactions
what is a homologous series
a ‘family’ of organic compounds with the same functional group
successive members of a homologous series differ from each other by having an extra carbon with 2 hydrogens bonded to it
what is the general formula for alkenes
CnH2n
why are alkanes used as fuels but alkenes aren’t
with alkenes there is incomplete combustion so they burn with a smokier flame and release less energy per mole
why are alkenes more reactive than alkanes
because of the c=c bond so molecules that react with alkenes add to the alkene across the double bond making it a single bond so it can bond to more molecules
what is the product of the reaction ethene + bromine (halogen)
dibromoethane (colourless)
what happens when an alkene reacts with hydrogen
addition of a hydrogen molecule causes the unsaturated alkene to become saturated (alkane) at 60c with the presence of a nickel catalyst
what happens when an alkene reacts with water (steam)
an alcohol is produced. it is a reversible reaction and energy is required to create a high pressure
how is the formula of an alcohol different from an alkane
remove a H atom from an alkane and add an -OH
what is the functional froup for alcohol
-OH
what is the functional group for carboxylic acids
-COOH
what is the functional group for esters
-COO-
how is ethanol made
fermenting suagrs from plants with yeast
what is the equation for fermentation
glucose= ethanol + carbon dioxide (in the presence of yeast)
how does ethene produce ethanol
reacting ethene and steam in the presence of a catalyst
what is the reaon for the combustion of ethanol (and methanol)
shows that alcohols are flammable and can be used as fuels. Ethanol burns with a clean blue flame
ethanol + oxygen = carbon dioxide + water
what happens when alcohols react with sodium
sodium + ethanol = sodium ethoxide + hydrogen
what happens when a sodium alkoxide is dissolved in water
produces a strongly alkaline solution
why do bottles of beer and wine taste and smell like vinegar when left open for too logn
the ethanol in the drink starts to oxidise from oxygen in the air and starts to form ethanoic acid
what is the equation for oxidation of an alcohol
ethanol + oxygen atoms from oxidising agent = ethanoic acid + water
what is the equation for a reaction of a carboxylic acid and a metal carbonate
carboxylic acid + metal carbonate = sodium ethanoate + water + carbon dioxide
why must acids dissolve in water before showing their acidic properties
in water all acids ionise (split up). strong acids ionise completely but weak acids don’t
why is carboxylic acid said to be a weak acid
most of the molecules stay as they are and only a small proprtion will ionise in their solutions so the carboxylic acid solution has a higher pH (lower conc of H+ ions) than a strong acid resulting in a slower reaction with metal carbonate
how are esters made
when a carboxylic acid reacts with an alcohol
