C9

Question 1

why test for ions must be unique

Answer 1

so results of test can let you determinewhich gas or ion is present rather than being uncertain which one

Question 2

flame tests to identify diff ionsin solids

Answer 2

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

Question 3

tests to identify ions in solids or sols

Answer 3

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

Question 4

chemical test for ammonia

Answer 4

damp red litmus turns blue

Question 5

test to identify car sulfate and chloride ii#ons in solid or sol

Answer 5

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

Question 6

instrumental methods of analysis

Answer 6

may improve-speed, sensitivity and accuracy of tests compared to lab tests
they are available

Question 7

data from a flame phototmeter

Answer 7

conc of ions in dilute sol-identify wqithna calibration curve
to identify metal ions by comparing data with referencer data

Question 8

formulae of alkanes

Answer 8

general formula= C(small n)H(2n+2) n=number of carbon atoms.
meth=1
eth=2
prop-=3
but=4

Question 9

why are alkanes saturated hydrocarbons

Answer 9

becasue carbon atoms joiined together by singke bonds

Question 10

alkense formulae

Answer 10

C(n)H(2n)
but-1-ene and but-2-ene=c(4)H(8)

Question 11

why alkened unsatirated

Answer 11

contain double carnbon bonds
it is a functional group and responsible for the typical reactions if alkenes

Question 12

reaction of ethen with brmine

Answer 12

no other procust so addition as combine
double bonds splits to react with other product

Question 13

distinguish between alkanes and alkenes

Answer 13

orange-brown brimin water
alkane=no change
alkene-water becomes colourless

Question 14

complete combiustion of alkenes and kanes

Answer 14

produce CO2 and water
oxidation of hydrocarbons
alkenes less likely to combust comoletely than alkanes
plentiful supply of O2

Question 15

What is a polymer

Answer 15

substance of high average realtive molecular mass made up of small repeating units

Question 16

ethen in polymeristaion reaction

Answer 16

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

Question 17

problems associated with polymers

Answer 17

-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

Question 18

dis and ads of recycling polymers

Answer 18

-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

Question 19

DNA as a polymer

Answer 19

-made from 4 different monomers called nucleotides
-starch us a polymer based n sugars
-proteins are polymers based on amino acids

Question 20

alcohol formulae

Answer 20

functionsal group=hydroxyl(-OH)
C(n)H(2n+1)OH

Question 21

how to form alkenes

Answer 21

alcohols can be dehydrated to form alkenes

Question 22

core prac=temp rise by alcohol combustion

Answer 22

-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

Question 23

carboxylic acid formulae

Answer 23

-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

Question 24

carboxylic acid properties

Answer 24

-typical acidic proerties

Question 25

ethanol oxidation

Answer 25

-to preduce ethanoic acid

Question 26

production of ethanol

Answer 26

-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

Question 27

fraf dis

Answer 27

-ethanol evaportaes more readily so seprated water and ethanol=conc sol

Question 28

size of nanoparticles

Answer 28

-around 100 time slarger than atoms and simple molecules

Question 29

nanoparyicluate materials

Answer 29

-large sa to vol ratio
-tiataniumm dioxide block sunlight in suncream and when nanoparticulate the white powder cannot be seen on skin

Question 30

risks of nano

Answer 30

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