C9 Flashcards
why test for ions must be unique
so results of test can let you determinewhich gas or ion is present rather than being uncertain which one
flame tests to identify diff ionsin solids
litium(red), sodium(yellow0, potassium(lilac), calcium(orange/red), copper(blue/green)
method:
-dip clean wire loop in solid sample of compound
-put loop into edge of blue flame on bunsen
-observe and record fkame colour produced
tests to identify ions in solids or sols
al-white dissolves inj excess sodium hydroxide sol
ca-white ni change in excess sodium hydrox sol
cu-blue
iron(2)-green
iron(3)brown
metyhod=add few droops of sol and ibserve and recvord
ammonium(NH4+)-add few drops then warm gently, ammonia gas produced if ions are presnet
chemical test for ammonia
damp red litmus turns blue
test to identify car sulfate and chloride ii#ons in solid or sol
carb-usedilute acid and identify CO2 evolved
sulfate-dilute hcl barium chloride sol-white precip forms if present
chloride/bromide/iodide(halide)-dilute nitric acid and silver nitrate sol
cl-white precip
br-cream precip
i-yellow precip
instrumental methods of analysis
may improve-speed, sensitivity and accuracy of tests compared to lab tests
they are available
data from a flame phototmeter
conc of ions in dilute sol-identify wqithna calibration curve
to identify metal ions by comparing data with referencer data
formulae of alkanes
general formula= C(small n)H(2n+2) n=number of carbon atoms.
meth=1
eth=2
prop-=3
but=4
why are alkanes saturated hydrocarbons
becasue carbon atoms joiined together by singke bonds
alkense formulae
C(n)H(2n)
but-1-ene and but-2-ene=c(4)H(8)
why alkened unsatirated
contain double carnbon bonds
it is a functional group and responsible for the typical reactions if alkenes
reaction of ethen with brmine
no other procust so addition as combine
double bonds splits to react with other product
distinguish between alkanes and alkenes
orange-brown brimin water
alkane=no change
alkene-water becomes colourless
complete combiustion of alkenes and kanes
produce CO2 and water
oxidation of hydrocarbons
alkenes less likely to combust comoletely than alkanes
plentiful supply of O2
What is a polymer
substance of high average realtive molecular mass made up of small repeating units
ethen in polymeristaion reaction
double carbon bond breaks open to slloow ethen molecules to join together to form single product
addition polymer formed is polyethen
made up of ethen monomers
problems associated with polymers
-not huge availability of starting materials
-landfill sites because not biodegradeable
-gases produced during disposal in combustion
-to recycle have to sort polymers whuch can be difficult and expensive to do
dis and ads of recycling polymers
-reduces prob of disposal and vol of crude oil used
-must eb separated/expensive
-can be cheapeer than crud oil tho
-better impact on environment
-reduces need for availibility of starting materials
DNA as a polymer
-made from 4 different monomers called nucleotides
-starch us a polymer based n sugars
-proteins are polymers based on amino acids
alcohol formulae
functionsal group=hydroxyl(-OH)
C(n)H(2n+1)OH
how to form alkenes
alcohols can be dehydrated to form alkenes
core prac=temp rise by alcohol combustion
-secure steel can over spirit burner
-measure and record mass with lid
-add 100cm3 of cold water and record temp
-place spirit burner under can and light wick(remove lid)
-stor water with thermomemter and put lid n once water increased by 20 degrees(put out flame)-record mass of spirit burner with lid and max temp of water
-reepat with diff alcohols
cahnge in mass=mass of fuel burned and compare change in temp per gram for each fuel to seed whuch most effective
carboxylic acid formulae
-functional group -COOH(carboxyl group)
-weak acids
-C(n)H(2n+1)COOH
n=number of carbon atoms mnus 1
-O atoms not joine
-double bond between 1 c and o
covalent bonds
carboxylic acid properties
-typical acidic proerties
ethanol oxidation
-to preduce ethanoic acid
production of ethanol
-fermentation of carbs in aqeous solution using yeast for enzymes
-glucose>ethanol+CO2(fermentation=anaerobic)
-concentrated with frac dis
-condition:
sugar dissolves in water and mixed with yeast
-air lock allows CO2 out but stops other gases getting in
-warm temp 25-35 for yeast enxymes to work
-yeast dies at 15% ethanol conc
slow reaction can take days or weeks
-if air present ethanoic acid produced by oxidation so taste like vinegar
fraf dis
-ethanol evaportaes more readily so seprated water and ethanol=conc sol
size of nanoparticles
-around 100 time slarger than atoms and simple molecules
nanoparyicluate materials
-large sa to vol ratio
-tiataniumm dioxide block sunlight in suncream and when nanoparticulate the white powder cannot be seen on skin
risks of nano
can be breathed in
can catalyse reactions in bod so could beharmful snd toxic
toxic sub can bind to them cos if sa to vol ratio
only recent so hard to determine risks
environmental issues
