Topic 9 Flashcards
Describe the colour you would expect from a flame test if lithium was present
Red
Describe the colour you would expect from a flame test if sodium was present
Yellow
Describe the colour you would expect from a flame test if potassium was present
Lilac
Describe the colour you would expect from a flame test if calcium was present
Orange-red
Describe the colour you would expect from a flame test if copper was present
Blue-green
Describe the chemical test for ammonia
Makes damp red litmus paper turn blue
It also forms a white smoke of ammonium chloride when hydrogen chloride gas,from concentrated hydrochloric acid, is held near it
Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained ALUMINIUM to test for cations
White (dissolves when an excess of NaOH is added)
Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained CALCIUM to test for cations
White
Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained IRON (II) to test for cations
Green
Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained COPPER to test for cations
Blue
Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained IRON (III) to test for cations
Brown
Describe what you would expect to see when NaOH is added to a sample that contained AMMONIUM to test for cations
Pungent smelling gas is produced and turns damp red litmus paper blue
Describe how a test for cations would be carried out
- add a small amount of the solution into a test tube
- add a few drops of sodium hydroxide to the solution
- record colour of precipitate
- add sodium hydroxide until it is in an excess
- Record the colour
Describe how flame tests for cations would be carried out
- Light the Bunsen burner and open air hole for a blue flame
- Take a sample of the test substance using a wire loop
- Hold the sample on the edge of the flame and observe a colour
What is the test for a SULFATE ANION
○ Add dilute HCl followed by barium chloride solution to the sample
○ A WHITE precipitate will form when sulfate ions are in this solution
What is the test for a CARBONATE ANION
Gas produced bubbled through limewater, if the limewater goes cloudy,the gas is CO2 (carbonates react with dilute acids to produce CO2)
What is the method for testing Chloride ion, Cl- , bromide ion, Br- , iodide ion, I- , using dilute nitric acid and silver nitrate solution
First add dilute nitric acid, followed by silver nitrate solution
○ Chloride gives a WHITE precipitate
○ Bromide gives a CREAM precipitate
○ Iodine gives a YELLOW precipitate
What are the first 4 alkanes
Methane
Ethane
Propane
Butane
What is the general formula of an alkane
CnH(2n+2)
Why are alkanes saturated carbons
Because they have no C=C bond
Explain how bromine water is used to distinguish between alkanes and alkenes 
Alkenes react with bromine water, turning it from orange to colourless – alkanes DO NOT react with bromine water
What is the general formula for alkenes
CnH(2n)
Describe how the complete combustion of alkanes and alkenes involves the oxidation of the hydrocarbons to produce carbon dioxide and water
The combustion of hydrocarbons releases energy. During combustion, the carbon and hydrogen in the fuels are oxidised to produce carbon dioxide and water
alkane/alkene + oxygen → carbon dioxide + water
Do alkanes OR alkenes undergo addition polymerisation
ALKENES
How do we show an addition polymerisation reaction
Carbon double bond is lost
Monomer is put in square brackets withlines from each C overlapping
n at the bottom right corner outside brackets
Why are alkenes unsaturated hydrocarbons
They contain a C=C double bond
What are polyesters
Condensation polymers
What is condensation polymerisation
When two different monomers react together producing a water molecule
How is an ester link formed
A molecule containing two carboxylic acid groups and a molecule containing two alcohol groups forms an ester link when they react together
What are some of the problems with the disposal of polymers
Most are go into landfill sites and some are burnt which releases toxic gases
Name an advantage and disadvantage of recycling polymers
Landfill sites is a waste of a nonrenewable resource as polymers are made from crude oil
Recycling means that less waste goes into landfill however this is expensive due to the collection and sorting
Name a polymer based on amino acids
Proteins
Name a polymer based on sugars
Starch
Name a polymer made from nucleotides
DNA
What is the functional group of an alcohol
-OH
How do alcohols differ in molecular formula
CH2
What is the functional group of carboxylic acids
-COOH
How is ethanoic acid produced
Ethanol is oxidised by:
Reacting with oxygen (burns in air)
Chemicals called oxidising agents
The action of microbes
How can you obtain a concentrated solution of ethanol
By fractional distillation
Works because ethanol has a lower boiling point than water
How big are nano particles compared to atoms
They consist of only a few 100 atoms
What are nano particles useful for
Sunscreen
Carbon nanotubes in tennis rackets
Future drug delivery systems
Why are nano particles useful for sunscreen
Absorb harmful ultraviolet light from the Sun but cannot be seen on the skin
What are the risks associated with the use of nano particles
Attract toxic substances to the surfaces
can be inhaled
take a long time to breakdown
If absorbed they an alter reactions in the body
List the properties of glass ceramics
Transparent
hard but brittle
poor conductors of heat and electricity
List the properties of clay ceramics
Opaque
hard but brittle
poor conductors of heat and electricity
List the properties of polymers
Transparent translucent or opaque
poor conductors of heat and electricity
often tough and ductile
List the properties of metals
Can be polished to a shine
good conductors of heat and electricity
hard tough and ductile
