organic chemical analysis 7 Flashcards
what is crude oil
a fossil fuel formed millions of years ago from the decay of dead sea creatures. It is a mixture of hydrocarbons
what are features of Alkanes
fully saturated
ends in ANE
c has 4 single bounds
general formula of Alkanes
CnH2n+2
first 5 alkanes
Meth Eth Prop But Pent
what are the properties of short chain hydrocarbons
small molecules low boiling point high volatility low viscosity high flamability
what are the properties of long chain hydrocarbons
large molecules high boiling point low volatility high viscosity low flammability
what is viscosity
how easily it flows
What is a fraction
a set of hydrocarbon molecules of similar size and boiling point
what is the processes of a fractionating column
Tower is hot at bottom,
all gases condense at different temperatures
The different fractions are collected as liquids at different temps
Smaller molecules have low boiling points and are collected at the top
what is produced in combustion
carbon dioxide + water
what is produced in incomplete combustion
carbon + carbon monoxide + water
what does oxidised mean
adding oxygen to produce an oxide
what is catalytic cracking
heat to vaporise at a low pressure
go over catalytic cracker to crack the hydrocarbons
goes into the distillation tower
What are the features of Alkenes
double bound
unsaturated
reactive
General formula of Alkenes
CnH2n
what is produced when a long alkane is cracked
short alkane + alkenes
Definition of pure
a pure substance is one that is made up of just one substance. That substance can be either an element or a compound
Melting and boiling points of a pure substance
specific temps(fixed points)
Melting and boiling point of an impure substance
do not have sharp melting and boiling points
What are formulations
are mixtures designed to produce a useful product
What is chromatography
used to separate substances in a mixture when all substances are soluble in the same solvent
How to measure Retention Factor
Distance moved by sample/distance moved by solvent
how to test for hydrogen
squeaky pop
how to test for oxygen
relight blow out splint
how to test for chlorine
litness paper bleaches
metal + acid makes
metal salt + hydrogen
hydrogen peroxide reacted by magnesium oxide makes
water + oxygen
metal carbonate + acid makes
metal salt + water + carbon dioxide
what is the flame test
test for various metal ions by heating your substance and seeing whether it burns with a distinctive colour flame
flame color of Lithium
crimsom
flame color of Sodium
yellow
flame color of Potassium
lilac
flame color of Calcium
orange-red
flame color of Copper
green
flame test proccess
clean a wire loop by dipping it in a dilute HCL and hold it over a blue flame
Dip the loop into the sample and record the color of the flame
You use the color to identify the ions
It only works on samples that contain a single metal ion
what is the colored precipitate test
adding a few drops of sodium hydroxide solution to a solution of the mystery compound to form a insoluble hydroxide
why does the colored precipitate test work
many metal hydroxides are insoluble and precipitate out of solution when formed.
color of copper precipitate in the colored precipitate test
blue
color of Iron 2 plus precipitate in the colored precipitate test
green
color of iron 3 plus precipitate in the colored precipitate test
brown
color of aluminium precipitate in the colored precipitate test
white
color of magnesium precipitate in the colored precipitate test
white
ionic equation of the colored precipitate test on calcium
Ca 2 plus + 2OH minus = Ca(OH)2
ionic equation of the colored precipitate test on calcium
Ca 2 plus + 2OH minus = Ca(OH)2
how do you know if sulfate ions are produced
white precipitate
how do you know if carbonate ions are produced
CO2 produced/limewater turns cloudy
how do you know if halide ions are present for
Iodide
Bromide
Chloride
yellow
cream
white
what and how does flame emission spectroscopy work
finds out what ions are present from there wavelengths
a sample is placed in a flame. As the ions heat up their electrons become excited. When the electrons drop back to their original levels they transfer light as energy. This passes through a spectroscope which can detect different wavelengths of light to produce a line spectrum
how does flame emission spectroscopy determine the ions present
combinations of wavelength emitted by an ion depends on it’s charge and it’s electron arrangement.
Each ion has a different wavelength.
what does the intensity of flame emission spectroscopy show
indicates the concentration of that ion
flame emission spectroscopy for mixtures what does it show
can be used to show more than one ion present
advantages of instrumental analysis
time saving more accurate sensitive fast small
disadvantages of instrumental analysis
expensive
needs training
disadvantage of non instrumental
large
less accurate
less sensitive
larger sample needed
