separate chemistry 2

Created by

mckayla hammond

Cards (62)

What colour flame is lithium?
Crimson red
What colour flame is sodium?
yellow
What colour flame is potassium?
lilac
What colour flame is calcium?
orange-red
What colour flame is copper?
blue-green
Describe the method for a flame test?
1) clean a in chrome wire loop in HCl
2) dip wire loop into metal
3) hold loop in clear part of a blue bunsen flame
How to test metals? (not flames)
add some sodium hydroxide, as many metal hydroxides are insoluble and have distinct colours, so we can see the precipitate.
What colour is the Al(OH)3 precipitate?
White, but then re dissolves in excess NaOH to be colourless (this is Al(OH)4)
What colour is the Ca(OH) precipitate?
white
What colour is the Cu(OH)2 precipitate?
blue
What colour is the Fe(OH)2 precipitate? (indicating Fe2+) 
Green
What colour is the Fe(OH)3 precipitate? (indicating Fe3+)
Brown
How do you test for ammonium?
Add NaOH to produce ammonia
Test for ammonia using damp red litmus, which should turn blue
How do you test for Halide ions?
Add dilute nitric acid and then silver nitrate solution
What halide ion tests do you need to know? (include colours of precipitate)
chloride - white precipitate of silver chloride
bromide - cream precipitate of solver bromide
iodide - yellow precipitate of silver iodide
How do you test for carbonates?
Use dilute acid and add it to the test tube that contains your mystery substance. Connect this to a test tube containing lime water. If the limewater goes cloudy, carbonates are present. (the CO2 supposedly produced should travel through the tube to the limewater)
What do you test for sulfate ions?
Add HCL to prevent non-sulphate ions reacting
Add barium chloride, a white precipitate of barium sulphate should form.
What is flame photometry?
an instrumental method that allows you to identify ions in a dilute solution by analysing the spectra of light frequencies of light emitted.
What are the advantages of using a machine to analyse an unknown substance?
- very sensitive (can even detect tiny amounts)
- very fast and tests can be automated
- very accurate as they remove human error
What are alkanes? 
saturated hydrocarbons containing only single bonds
What is the general formula of alkanes?
CnH2n+2
What is the general formula of alkenes?
CnH2n
What is the functional group of alkenes?
C=C
What are the uses of alkenes?
To make plastics and alcohol
What are the uses of alkanes?
fuels
What is the source of alkenes?
cracking, dehydrating alcohols
What is the source of alkanes?
crude oil
How do you test for alkanes/ alkenes?
> bromine water is an orange liquid
> Br water does NOT react with alkanes so it stays orange
> it DOES react with alkenes - it decolourises water from orange to colourless
In combustion reactions, what happens to hydrocarbons?
they are oxidised
What happens in an addition polymerisation reaction?
Unsaturated monomer molecules join together to form saturated polymers. The double bond opens up, allow two new bonds (one on each end of the molecule) to form.
What are the properties and uses of poly(ethene)?
- flexible, electrical insulator, cheap
- used in plastic bags, bottles, wire insulation
What are the properties and uses of poly(propene)? 
- flexible, strong, tough, mouldable
- crates, furniture, ropes
What are the properties and uses of poly(chloroethene)? (PVC)
- tough, cheap
- window frames, water pipes
What are the properties and uses of poly(tetrafluoroethene)? (PTFE)
- unreactive, tough, non-stick
- non-stick pans, waterproof clothing
Name some examples of naturally occurring polymers?
- DNA (nucleotide monomers)
- protein (amino acid monomers)
- carbs (sugar monomers)
What are dicarboxylic acid monomers? 
They contain 2 carboxylic acid
What are diol monomers?
They contain 2 alcohol groups
When do polyesters form? 
When dicarboxylic acid monomers and diol monomers react together in a condensation reaction
What is the functional group of an ester? 
Ester link (-COO-)
What is lost in a condensation reaction?
water molecule