Flashcards in Topic 9 - Seperate Chemistry Deck (75):
What colour flame would Li+ ions give off of present in the flame test for metal ions ?
What colour flame would be given off when Na+ ions are present in sample?
What colour would K+ give off in the flame test for metal ions?
What colour flame would Ca2+ give off in the flame test?
What colour flame would be given off by Cu2+ in the flame test for metal ions ?
Describe the method for the flame test - for metal ions...
Firstly dip the wire loop into hydrochloride acid to remove impurities.Place loop in sample and that into outer blue flame of Bunsen burner
2 methods to test for metal ions ?
Flame test and Cation test
What colour is the precipitate formed from Al3+?
White, however it redissolves with excess NaOH to become colourless.
What colour is the precipitate of Ca2+ with NaOH?
What colour is the precipitate of Cu2+?
What colour is the precipitate of Fe2+?
What colour is the precipitate formed from Fe3+ ?
Red or brown
Method to form a coloured precipitate ?
Take a small sample of solution and test it drop wise with sodium hydroxide(NaOH)
What do you add to form a coloured precipitate ?
Sodium Hydroxide (NaOH)
Test for Ammonium Ions ?
Add sodium hydroxide solution, then heat and test if the gas given off is the ammonia gas. We can heck that by placing a red damp Lito is paper over the gas and if it turns blue then it contains ammonium ions..
What are the anion tests ?
Tests for halide, carbonates
and sulfate ions.
What are the halide ions?
Bromide, iodide and chloride
What is the method for the halide test?
1. To solution add nitric acid
2. Add silver nitrate
3. Watch the colour change of the precipitate
What colour is the chloride precipitate?
What is the chemical formula when chloride undergoes a halide year?
Ag+ + Cl- = AgBr
What colour is the precipitate of bromide after a halide test?
What is the formula of bromide precipitate after it undergoes a halide test?
Br- + Ag+ = AgBr
What is the formula of iodide after a halide test?
Ag+ + I- = AgI
What colour is the precipitate of iodide after it undergoes the halide test?
What is the method for the Carbonate test?
1. Add a dilute acid
2. If carbonates are present solution will fizz or bubble
What is the formula after a test for carbonates ?
Co2- + 2H+ = Co2 + H2O
How else can we check if carbon dioxide is given off in the carbonate test?
Use limewater , when CO2 present it will become milky
What is the method for the sulfates test?
1. Add hydrochloric acid
2. Add barium chloride.
3. Check if the solution turns white, this means sulfates are present
Formula after the test for sulfates ?
Ba2+ + SO(4)2- = BaSo4
What is the general formula for alcohols ?
Cn + H2n+1 OH
What happens to alcohols when they’re oxidised?
They become carboxylic acids
Example of an alcohol?
What functional group are alcohols a part of ?
What is the general formula for carboxylic acids ?
Cn-1 + H2n-1 COOH
What are alkenes?
A homologous series of unsaturated hydrocarbons with a C=C functional group
What are alkanes?
A homologous series of saturated hydrocarbons.
functional group o carboxylic acid ?
how do you test for an alkene ?
add bromine water and shake together - alkene will decolourise the water from orange. This is an addition reaction as bromine will be added across the alkene CC double bond
what are polymers?
substances made after joining monomers together.
what are addition polymers?
substances made from unsaturated monomer molecules (alkenes) which open up their double bond and join together to make a chain
what names do addition polymers have ?
poly(and whatever alkene was used )
what are the properties of poly(ethene) and uses..
what are the properties of poly(propene) and uses ...
PVC properties and uses
properties and uses of poly(tetrafluoroethene)
what is condensation polymerisation?
where two different types of monomers with atleast 2 functional groups react together making bonds and forming polymer chains and another element
examples of naturally occurring polymers ?
in condensation polymerisation the functional groups mix to make a new element and the left others make a separate one
plastic is a type of
problems with disposing polymers in landfills
valuable land is quickly used up.
most polymers are non-biodegradable so they stay there for a long time
why do polymers end up in a landfill ?
as they’re difficult or expensive to separate or recycle
problems with disposing polymers by combustion
toxic gases are released
co2 released that contributes to greenhouse effect
burning plastics produces a lot of
energy that can be used for electricity
advantages of recycling
reduced the amount of non biodegradable filling up landfills sites
reduced emissions of greenhouse and toxic gases
less water and energy resources used than making new polymers
reduced amount of crude oil necessary
more jobs and saves money
disadvantages of recycling
polymers must be separated by type before they can be melted or reformed into new products - this can be expensive or difficult.
polymers can only be recycled a finite number of times as they lose strength
dangerous gases can be released into the atmosphere
what is fermentation?
a process of using yeast to convert carbohydrate (sugars) into alcohol
what does yeast contain ?
summarise the method of fermentation.
mix yeast with carbohydrate (e.g.glucose)
seal and leave in warm place
keep in anerobic conditions to avoid oxidation
when concentration of alcohol reaches 10 or 20 % fermentation stops as yeast gets killed off
how can we make a more concentrated alcohol after fermentation ?
use fractional distillation
how does fractional distillation work ?
since ethanol has a lower boiling point than water it will evaporate first and later condense making it possible to collect
why can alcohols be used as fuels ?
as when they’re burned they release a lot of energy
go through the practical investigating how burning alcohol is an effective fuel.
1.put alcohol into spirit burner and measure mass using a mass balance
2.measure a 100cm cubed of water into a copper calorimeter.
3.insulate copper calorimeter by using a draught excluder then cover with insulating lid but before place a thermometer inside.
4.measure initial temperature and wait until temperature has increased by e.g. 20 degrees
5.stir throughout experiment and reweight alcohol
6.repeat but keep mass length from burner and length of flame and alcohol moles equal
how big is the diameter of a nanoparticle ?
2.5 x 10^-8
are nanoparticles bigger than atoms ?
are fullerenes nanoparticles?
what are the uses of nanoparticles ?
good catalysts since the high surface area to volume ratio so there is more frequent collisions
fullerenes can be used to deliver drugs or as lubrication
can make sports equipment stronger but not much heavier
what is poly(styrene)used for ?
what is poly(propene) used for ?
what are the 2 ceramics ?
glass and clay
how is clay formed ?
formed from weathered and decomposed rock and when put under high temperatures it is hardened making it useful for buildings
how is glass made ?
by heating limestone and sodium carbonate until it melts
what are composites ?
made from a material being embedded in matrix/binder
what are the properties of polymers?
often flexible and can be moulded
cheaper than other materials
less dense than metals and ceramics
heat and electricity insulators
can degrade and breakdown
what are the properties of ceramics ?
insulators of heat and electricity
brittle and stiff
strong and hard wearing
don’t degrade or corrode