Topic 9 - Separate Chemistry 2

why must the test for an ion be unique

otherwise ions may have similar results and it would be impossible to know which is which

flame test result for:

lithium

sodium

potassium

calcium

copper

red

yellow

lilac

orange

green-blue

test for precipitates

use sodium hydroxide

colour of copper in sodium hydroxide

blue

colour of iron II in sodium hydroxide

green

colour of sodium hydroxide in iron III

brown

color of calcium in sodium hydroxide

white

colour of aluminium in sodium hydroxide

white

test for ammonia

damp red litmus paper blue

test for sulfate ions

add dilute hcl and barium chloride

white precipitate formed

test for carbonate ions

makes acid bubble

test for halides

dilute nitric acid and silver nitrate

chloride - white

bromide - cream

iodie - yellow

alkane formula

CnH2n+2

alkene formula

CnH2n

test for alkenes

decolourised bromine water, as the double bond is able to react with bromine

use of polyethene

flexible, good insulator, cheap

plastic bags, plastic bottles

use of polypropene

flexible, shatterproof, high softening point

buckets and bowls

polychloroethene

tough, cheap, long lasting

window frames, gutters, electrical insulation

polytetrafluoroethene

tough slippery, resistant to corrosion

non stick coatings, containers for corrosive substances

carboxylic acid + alcohol

ester link and water molecule

Alcohol general formula

CnH2n+1OH

Carboxhylic acids general formula

CnH2n+1COOH

Oxidation of alcohol

Carboxhylic acid

members of a homologous series:

similar reactions as same functional group

Nanoparticle size

consists only of a few hundred atoms

bigger than atoms and molecules

properties of nanoparticles

high surface area to volume ratio

used in suncreams (absorb UV), drug delivery, and tennis rackets

problems with nanoparticles

can be breathed in, take a long time to break down, and attract toxic substances