Separate Chemistry Flashcards
Why must the test for ions be unique
As you wouldn’t be able to know the specific ion if more than one ion gave the same result
What colour is lithium ions in the flame test
Red
What colour is sodium ions in the flame test
yellow
What colour is potassium ions in the flame test
lilac
What colour is calcium ions in the flame test
orange-red
What colour is copper ions in the flame test
blue-green
How do you preform a flame test
Hold a sample you wish to test on a wire in a roaring Bunsen flame and observe colour change
Describe tests to show the presence of the following ions in solids or solutions
- Add a few drops of sodium hydroxide solution to a solution of your unknown compound
- Forms an insoluble hydroxide
- Depending on the colour of precipitate produced from the metal ion it can be identified
What colour precipitates form when sodium hydroxide reacts with aluminium ions
White precipitate (dissolves when excess NaOH is added)
What colour precipitates form when sodium hydroxide reacts with calcium ions
White precipitate
What colour precipitates form when sodium hydroxide reacts with copper(II) ions
Blue precipitate
What colour precipitates form when sodium hydroxide reacts with iron(II) ions
Green precipitate
What colour precipitates form when sodium hydroxide reacts with iron(III) ions
Brown precipitate
What is observed when sodium hydroxide reacts with ammonium ions
- Pungent-smelling gas produced
- Gas produced turns damp red litmus paper blue
What is the test for ammonium ions
- Add a few drops of dilute sodium hydroxide solution, then warm gently.
- Ammonia gas is produced if ammonium ions are present.
- Confirm that the gas is ammonia - damp red litmus paper turns blue.
What is the test for carbonate ions
- Add a few drops of dilute hydrochloric acid.
- Bubbles are produced if carbonate ions are present.
- Confirm that the gas is carbon dioxide - limewater turns milky.
What is the test for sulphate ions
- Add a few drops of dilute hydrochloric acid,
- add a few drops of barium chloride solution.
- A white precipitate forms if sulfate ions are present.
What is the test for halide ions
- Add a few drops of dilute nitric acid,
- Add a few drops of silver nitrate solution.
- Observe and record the colour of any precipitate formed.
What colour precipitate does does chloride form in dilute nitric acid and silver nitrate solution
White precipitate
What colour precipitate does does bromide form in dilute nitric acid and silver nitrate solution
cream precipitate
What colour precipitate does does iodide form in dilute nitric acid and silver nitrate solution
yellow precipitate
What are two examples of instrumental analysis
- gas chromatography
- mass spectrometry
What are the positives of instrumental analysis
- Improve sensitivity
- Improve accuracy
- Increases speed of the test
What is a flame photometer used for
- Identifying metal ions in a sample
- determining the concentration of metal ions in a solution
How does a photometer work
- Sample is put into a flame and the light given out is passed through a photometer
- Output is a line spectrum that can be analysed to identify metal ions in the solution and measure their concentrations
What are the first 4 alkanes
- Methane
- Ethane
- Propane
- Butane
Why are alkanes saturated hydrocarbons
- They don’t possess any double or triple bonds
- Are compounds made of hydrogen and carbon only
What are the first 3 alkenes
- Ethene
- Propene
- Butene
Why are alkenes unsaturated hydrocarbons
- Contain 1 or more C=C bonds
- Are compounds made of hydrogen and carbon only
What is the reaction of ethene + bromine
Ethene + bromine -> 1,2-dibromoethane
this reaction works the same for any alkene or any halogen
How is bromine water used to distinguish between alkenes and alkanes
- Alkenes react with bromine water (go from orange to colourless)
- Alkanes don’t react with bromine water
Describe complete combustion of alkanes/alkenes
- Alkane/alkene + oxygen → carbon dioxide + water
- Hydrocarbons oxidise to produce products
What is a polymer
A substance made from long chains of
small repeating units
What is addition polymerisation
A reaction where many small molecules (monomers) join to create large molecules (polymers)
Why can any alkene be used as a monomer
They contain a C=C bond
What is the difference between the structure of a monomer and the structure of an addition polymer
all monomers involved in addition polymerisation have a double bond
What is the properties of Poly(ethene)
- Flexible
- Cheap
- Electrical insulator
What are the uses of Poly(ethene)
- Plastic bags & bottles
- Coating on electrical wires
Properties of poly(propene)
- Flexible
- Strong
Uses of poly propene
Buckets and crates
Properties of chloroethene (PVC)
- Tough
- Cheap
- Long lasting
Uses of poly chloroethene (PVC)
Window frames
Properties of PTFE
- Tough
- Non-stick
Uses of PTFE
Non stick coating on pans
Why are polyesters condensation polymers
dicarboxylic acid and diol molecules join releasing a water molecule for every ester link made
How is a polyester formed when a monomer molecule containing two carboxylic acid groups is reacted with a monomer molecule containing two alcohol groups
- the dicarboxylic acid loses the OH group off of each COOH group
- the di-alcohol loses the H off of each OH group
- the remaining molecules join together to make a polyester
How a molecule of water is formed each time an ester link is formed
the OH and H groups combine to make H2O
Advantages of recycling polymers
- Better for the environment
- Saves crude oil
- More economically viable
disadvantages of recyling polymers
- Difficult and expensive to seperate
What are different types of polymers and how
- DNA - nucleotides
- Starch - sugars
- Proteins - amino acids
What are the first 4 alcohols
- Methanol
- Ethanol
- Propanol
- Butanol
What is the functional group of alcohols
-OH
Core practical: Investigate temperature rise by the combustion of alcohols
- the temperature is raised more as the
chain length of the alcohols increases - Combustion of longer chain alcohols release more energy
What is the functional group for carbolic acids
-COOH
What are the first 4 four members of the carboxylic acids
- Methanolic
- Ethanoic
- Propanoic
- Butanoic
What happens when you oxidise an alcohol
It becomes a carboxylic acid
How can ethanol be produced
- Fermentation with yeast
- It is produced from carbohydrates
- Kept under anaerobic conditions
What is the anaerobic equation
Glucose -> ethanol + carbon dioxide
How do you obtain a concentrated solution of ethanol by fractional distillation
- Ethanol conc = 15% from fermentation
- Water and ethanol solution are heated
- Ethanol evaporates first - having a lower boiling point - cools then condenses
- Water left evaporates
What is the size of an atom
0.1 nm
What is the size of a nanoparticle
1 nm to 100 nm
Why are nanoparticles useful for their uses
- Contains fullerenes
- High SA:V ratio ( good catalysts)
- Layers slide over each other so is good for sunscreen
- Can conduct electricity
What are the risks of nanopaticles
- Could enter the bloodstream and cause harm (cataylse reactions)
- A lot of effects are unknown
What are the properties of glass ceramics
- Transparent
- Hard
- Brittle
- Poor heat and electrical conductors
Uses of glass ceramics
- Windows
- Bottles
Qualities of clay ceramics
- Opaque
- Hard
- Brittle
- Poor heat and electrical conductors
Uses of clay ceramics
- Bricks
- Porcelain
Qualities of polymers
- Can be made transparent/translucent/opaque
- Poor heat and electrical conductors
- Can be tough or doctile
Uses of polymers
- Plastic bags
- Bottles
Qualities of metals
- Shiny
- Good heat and electrical conductors
- Hard
- Tough
Uses of metals
- Cars
- Bridges
- Electrical cables
