C10

Question 1

what is a functional group

Answer 1

eg c=c grouping

gives a ‘family’ of organic compounds their characteristic reactions

Question 2

what is a homologous series

Answer 2

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

Question 3

what is the general formula for alkenes

Answer 3

CnH2n

Question 4

why are alkanes used as fuels but alkenes aren’t

Answer 4

with alkenes there is incomplete combustion so they burn with a smokier flame and release less energy per mole

Question 5

why are alkenes more reactive than alkanes

Answer 5

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

Question 6

what is the product of the reaction ethene + bromine (halogen)

Answer 6

dibromoethane (colourless)

Question 7

what happens when an alkene reacts with hydrogen

Answer 7

addition of a hydrogen molecule causes the unsaturated alkene to become saturated (alkane) at 60c with the presence of a nickel catalyst

Question 8

what happens when an alkene reacts with water (steam)

Answer 8

an alcohol is produced. it is a reversible reaction and energy is required to create a high pressure

Question 9

how is the formula of an alcohol different from an alkane

Answer 9

remove a H atom from an alkane and add an -OH

Question 10

what is the functional froup for alcohol

Answer 10

-OH

Question 11

what is the functional group for carboxylic acids

Answer 11

-COOH

Question 12

what is the functional group for esters

Answer 12

-COO-

Question 13

how is ethanol made

Answer 13

fermenting suagrs from plants with yeast

Question 14

what is the equation for fermentation

Answer 14

glucose= ethanol + carbon dioxide (in the presence of yeast)

Question 15

how does ethene produce ethanol

Answer 15

reacting ethene and steam in the presence of a catalyst

Question 16

what is the reaon for the combustion of ethanol (and methanol)

Answer 16

shows that alcohols are flammable and can be used as fuels. Ethanol burns with a clean blue flame
ethanol + oxygen = carbon dioxide + water

Question 17

what happens when alcohols react with sodium

Answer 17

sodium + ethanol = sodium ethoxide + hydrogen

Question 18

what happens when a sodium alkoxide is dissolved in water

Answer 18

produces a strongly alkaline solution

Question 19

why do bottles of beer and wine taste and smell like vinegar when left open for too logn

Answer 19

the ethanol in the drink starts to oxidise from oxygen in the air and starts to form ethanoic acid

Question 20

what is the equation for oxidation of an alcohol

Answer 20

ethanol + oxygen atoms from oxidising agent = ethanoic acid + water

Question 21

what is the equation for a reaction of a carboxylic acid and a metal carbonate

Answer 21

carboxylic acid + metal carbonate = sodium ethanoate + water + carbon dioxide

Question 22

why must acids dissolve in water before showing their acidic properties

Answer 22

in water all acids ionise (split up). strong acids ionise completely but weak acids don’t

Question 23

why is carboxylic acid said to be a weak acid

Answer 23

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

Question 24

how are esters made

Answer 24

when a carboxylic acid reacts with an alcohol

Question 25

what is the equation for making an ester

Answer 25

alcohol + carboxylic acid = ester + water ( in the presence of a catalyst, usually sulfuric acid)