chem paper 2
what is an alkane
a saturated hydrocarbon
what is a homologous series
a series that has similiar properties throughout
trends in alkanes as you go down the group
boiling point increases as you go down
shorter chains are more volatile-evaporate easier
more viscous as length is increased
shorter chains are more flammable
what order do you balance an equation in
carbon hydrogen oxygen
what kind of reaction is cracking
thermal decomposition
what is the process of catalytic cracking
vaporise long chain hydrocarbon
have hot powdered aluminium
pass vapour over catalyst so it splits into shorter chain hydrocarbons
process of steam cracking
vaporise long chain hydrocarbon
mix item with steam
heat the item to very high temperature
long chain hydrocarbons are broken down
what does cracking do to long chain alkanes
shorter alkane and a alkene
what is different between alkanes and alkenes
alkenes are unsaturated and have a double carbon bond
what is the test for presence of a double bond
add alkene to bronine water
double bond present then water goes from orange to colourless
what is the general formula for an alkane
CnH2n+2
what is the general formula for an alkene
CnN2n
what happens in hydrogen addition (hydrogenatation)
hydrogen addition with alkenes and allows hydrogen atoms to join to form an alkane
REQUIRES CATALYST
water(steam) addition (hydration)
hydration with an alkene forms an alkene as the carbon carbon double bond opens up an allows h and OH to join
REQUIRES CATALYST
how to seperate the water ethene and ethanol
condense as ethene has a low bp to leave water and ethanol
then distill the water and ethanol
halogen addition
carbon carbon double bond opens up and halide ions join on
how to name a haloalkane
di(halogen)(alkane)
what is the functional group for an alcohol
OH
what is the general formupa for an alchohol
CnH2n+1OH
properties of an alcohol
flammable can undergo complete combustion
soluble and dissolve in water to form a neutral Ph
when reacted with an oxidising agent form carboxylic acid
uses of alcohols
used as fuels
solvents to dissolve fats and oils
functional group of a carboxylic acid
COOH
what is the formula for methanoic acid
HCOOH
what is the general formula for carboxylic acids
CnH2n+1COOH
why are carboxylic acids weak acids
dont fully ionise in water
what does a carboxylic + metal carbonate make
salt + water + carbon dioxide
how are carboxylix acids made
reacting an alcohol with an oxidising agent
what is special about the bond between CO in COOH
there is a double bond between C and O
what is the functional group for an ester
COO
properties of an ester
volatile
sweet and fruity smells
what is the reaction for an ester and with the example you need to know
carboxylic acid + ethanol -> ester + water
ethanoic acid + ethanol -> ethyl ethanoate + water
what do you need for condensation polymerisation
2 different monomers
important thing in order for condensation polymerisation to take place
there needs to be 2 different functional groups
each monomer needs atleast two lots of the functional group
how does condensation polymerisation work
dicarboxylic acid gives up its OH and diol gives up its hydrogen from its OH group to form water
left over CO bonds directly to the O to form a COO ester linkage
what is a polypeptide
long chain of amino acids
naturally occuring polymers
starch
glucose
cellulose
naturally occuring monomers
glucose
fructose
what is a pure substance
a single element or compound that melts at a specific fixed temperature
what is a formulation
complex mixture that has been designed as a useful product
fuels
paint
fertillisers
paper chromatography method
draw a pencil line on filter paper 5cm up
add sample of ink
suspend filter paper in beaker containing shallow amount of solvent
dont submerge pencil line
wait for solvent to move up the paper
different solibilities mean colours travel at different speeds
what is the mobile phase
substance molecules can move in
liquid or gas
what is the stationary phase
substance molecules cant move in
solid or THICK liquid
what is the correlation between material and speed it moves
more soluble materials are more attracted to the mobile phase
how to calculate an Rf value
distance travelled by substance
--------------------------------
distance travelled by solvent
test for chlorine
test tube of sample gas
add damp blue litmus paper
if present it is bleached
test for oxygen
glowing splint
place splint in test tube full of sample
splint is relit if oxygen is present
test for hydrogen
test tube of sample gas
add lit splint
if present there is a sqeaky pop
test for carbon dioxide
connect a bung to a sample of gas in beaker flowing into a test tube of limewater
funnel gas through
if present limewater turns cloudy
test for carbonates
add an acid to your carbonate
carry out the test for carbon dioxide as it is a product of the reaction
how to test for sulfate
add dilute HCL to get rid of carbonate
add barium chloride
should form a white precipiate
test for halide ions
add dilute nitric acid to get rid of impurities
add silver nitric acid to form a precipitate
Cl white precipitate
br cream precipitate
I yellow precipitate
differences between instrumental methods and manual tests
manual
basic and cheap
instrumental methods
expensive methods
more accurate
more sensitive
very fast
how to carry out a flame test
place small amount of sample onto loop
put loop into roaring flame
observe colour change
repeat with different loop
cons of the flame test
hard to distinguish with low concentration
samples can contain a mixture and. can mask the other metals
what colours does a flame go with metals
lithium crimson
sodium yellow
potassium lilac
calcium orange/red
copper green
what is potable water
water that has low levels of dissolved salts and doesnt have high amount of microbes
how to make water potable
collect water
pass through filter beds to temove suspended materials
sterilised with chlorine
what two methods are used to make sea water potable
distilation
reverse osmosis
steps of waste water treatment
sewage is screener by mesh to remove twig
let sewage sit in a sediment tank to undergo sedimentation
when the sewage sinks to the bottom you are left with light effluent
effluent is broken down by microorganism aerobically to make potable water
sludge is broken doen anaerobically to form methane
if water is toxic add chemicals to precipitate out methals and add UV light
process of phytomining
plants are grown in land containing low grade copper ores
plants absorb the metal compounds as nutrients ans concentrate it in their tissue
plants are harvested and burned
ash contains relatively high concentration of copper
process of bioleaching
bacteria are mixed with low grade copper ores
bacteria carry out chemical reactions and break down ores to form a leachate
leachate contains wanted metal compounds
to get copper undergo a displacement reaction with iron
requires high temperatures
what is given off when a metal is added to an alcohol
hydrogen
how to test for a carbonate
react wirh an acid and then do a carbon dioxide test
how to test for a sulphate ion
react with hydrochloric acid then barium chloride and it should turn white
metal hydroxide tests
add sodium hydroxide to calcium ions
magnesium ions
aluminium ions to form white precipitate
add excess to aluminium to redissolve
flame test between last two
what is the general formula for the metal hydroxide test
metal compund + sodium hydroxide -> sodium compound + metal hydroxide
what colour is copper II in sodium hydroxide
blue
what colour is iron III in sodium hydroxide
brown
what colour is iron II in sodium hydroxide
green
how is soda lime glass made
heatint sand sodium carbonate and limestone
how is borisilicate glass made
sand and boron trioxide with a higher melting point than soda lime glass
what is a composite
combination of a metal and mon metal with one binding the other resulting in strong lightweight materials
where are the potassium chloride and the potassium sulphate mined from
the ground
phosphate roxk + nitric acid
phosphoric acid and calcium nitrate neutralise with ammonia to get ammonium phosphate
phosphate rock + sulfuric acid
single super phosphate
calcium sulfate and calcium phosphate
phosphoric rock + phosphoric acid
triple superphosphate
difference between making fertilisers in a lab and in industry
lab
simple
low conc less heat
crysyalisation is slow
industry
expensive and complex
high conc very exothermix
heat produced evaporated water to make concentrated ammonium nitrate
why do thermosoftening polymers melt
dont have links between layers and can move over each other when heated
why do thermosetting polymers not melt
strong links arent broken when melted
what temperature and pressure in haber process
450 degrees
200 atmospheres
what does sulphur dioxide cause
acid rain
what do nitrogen oxides cause
breathing problems
what is galvanising
using zinc as a sacrificial metal
what is bronze made of
copper and tin
what is brass made of
66copper 34zinc