Chemistry 3B

Sulphate solubility
If a solution of any sulphate is added to a solution of a group 2 metal compound then a precipitate is
likely.
Group 2 ion in
solution
Effect of adding a sulphate
solution
Mg
2+
No precipitate, MgSO4 is soluble
Ca
2+
White precipitate of CaSO4
Sr
2+
White precipitate of SrSO4
Ba
2+
White precipitate of BaSO4
Hydroxide solubility
If sodium hydroxide is added to a solution of a group 2 compound then a precipitate is likely.
Group 2 ion in
solution
Effect of adding a hdro!ide solution
Mg
2+
"aint #hite precipitate of Mg$O%&2
Ca
2+
"aint #hite precipitate of Ca$O%&2
Sr
2+
"aint #hite precipitate of Sr$O%&2 on
standing
Ba
2+
No precipitate, Ba$O%&2 is soluble
Heating carbonates and nitrates
Substance Effect of heat
'ithiu( and all group 2
carbonates
Carbon dio!ide detected
Sodiu( and potassiu(
carbonates
No effect $e!cept #ater of crstallisation (a be gi)en
off&
Sodiu( and potassiu( nitrates O!gen onl gas e)ol)ed
'ithiu( and all group 2 nitrates Nitrogen dio!ide and o!gen e)ol)ed
Action of heat on compounds
Carbonates - Carbon dioxide is given off.
Hydrogencarbonates - Carbon dioxide and ater formed.
!roup " nitrates - #itrite and oxygen formed.
!roup 2 nitrates - $xide% bron fumes of nitrogen dioxide and oxygen formed.
&istinguishing beteen hydrocarbons
Alkane' (urn )oxidise)combust them. *hey ill burn ith a yello flame and form C$2 and H2$
+limited supply of C$,.
Alkene' A yello% sootier flame is produced +due to the extra carbon and higher ratio of
carbon'hydrogen,.
Identifying some functional groups
Alkene - Add to orange bromine ater. *he alkene ill decolourise it.
Halogenalkane - Heat ith sodium hydroxide solution. Acidify ith dilute nitric acid and then test
ith silver nitrate solution as ith inorganic halides.
Alcohols or carboxylic acids containing C-$H - In a dry test tube +i.e. dry alcohol,% add -Cl.. /isty
fumes of HCl are produced% hich turns blue litmus paper red.
&istinguishing beteen different classes of alcohol
Primary - Add -Cl.. 0arm it ith a1ueous potassium dichromate +22Cr2$3, and dilute H2S$4. /isty
fumes are given off and the colour changed from orange to green --5 aldehyde.
Secondary - /isty fumes% changes to green --5 ketone.
Tertiary - /isty fumes% no colour change.
Specification
f, interpret 1uantitative and 1ualitative results.
g, devise and plan simple experiments based on the chemistry and techni1ues summarised in a to e above
#ormally the last 1uestion on the paper. It ill ask you to identify certain compounds from four. 6.g.
titrations% ho to make a standard solution% ho to titrate% identify 7C$8 hen heating it here 7 is a
group 2 metal ion.
h, evaluate error in 1uantitative experiments see Appendix I for material available to assist centres in
teaching this area -ercentage error 9 absolute uncertainty)actual value x "::;
<, comment on safety aspects of experiments based on supplied data or recall of the chemistry of the
compounds listed in =nits l and 2. Safety considerations should relate to specific experiments not be of a
general nature it ill be assumed that students ear eye protection during all practical ork.
Halogens are toxic and harmful by inhalation% although iodine is much less so than chlorine or bromine%
because it is a solid. Chlorine and bromine must alays be used in a fume cupboard. >i1uid bromine
causes serious burns an must be handled ith gloves.
Ammonia is toxic. Concentrated ammonia solutions should be handled in the fume cupboard.
Concentrated mineral acids are corrosive. If spilt on the hands% ashing ith plenty of ater is usually
enough% but advice must be sought. Acid in the eye re1uires immediate attention and prompt professional
medical attention.
(arium chloride solution and chromates and dichromates are extremely poisonous and so should be used
in the fume cupboard)should not be inhaled.
Sodium or potassium hydroxide or concentrated ammonia in the eye is extremely serious and must alays
receive professional and immediate attention. Sodium hydroxide and other alkali metal hydroxides are
amongst the most damaging of all common substances to skin and other tissue. 0ear gloves% goggles and
an apron hen handling these solutions in high concentrations.
!eneral safety
*oxic)carcinogenic ? use gloves% fume cupboard
@lammable ? 0ater baths% no naked fumes.
Harmful gases ? =se fume cupboard
Corrosive ? ear goggles)gloves
Spillage of concentrated acid ? ash ith plenty of ater.
tests
Ion
Formu
la
Test Observations
Carbonate CO*
2+
Test 1
%eat the solid in a test tube #ith a Bunsen burner,
-t should deco(pose producing the o!ide and carbon
dio!ide, E,g,
.est for the gas using li(e#ater solution,
'i(e#ater should turn fro( colourless
to cloud in the presence of carbon
dio!ide due to precipitation of calciu(
carbonate,
Test 2
/dd dilute %Cl to the solid,
.est for the gas e)ol)ed using li(e#ater solution,
0igorous effer)escence,
'i(e#ater should turn fro( colourless
to cloud in the presence of carbon
dio!ide due to precipitation of calciu(
carbonate,
Hydrogencarbona
te
%CO*
+
Test
/dd calciu( chloride to a hdrogencarbonate solution,
No precipitate for(s since calciu(
hdrogencarbonate is soluble,
Sulphate $0-& SO4
2+
Test
/dd bariu( chloride solution acidified #ith dilute %Cl to
the test solution,
White precipitate of bariu( sulphate
for(s,
Sulphite SO*
2+
Test
War( the sulphite #ith dilute %Cl,
.est for gases using acidified potassiu( dichro(ate$0-&
solution $or paper&
.he solution turns green,
Chloride Cl
+
Test 1
/dd concentrated sulphuric acid to the solid chloride,
White stea( acidic fu(es are seen +
%Cl fu(es,
Test 2
/dd dilute nitric acid to a solution of a chloride to acidif
the solution, .his eli(inates an carbonates or sulphites,
/dd sil)er chloride to the solution,
/dd dilute a((onia solution,
White precipitate of /gCl for(s,
Solid dissol)es,
Bromide Br
+
Test 1
/dd concentrated sulphuric acid to the solid bro(ide,
Stea( bro#nish acidic fu(es are seen,
Test 2'
/dd dilute nitric acid to a solution of a bro(ide to acidif
the solution, .his eli(inates an carbonates or sulphites,
/dd sil)er chloride to the solution,
/dd concentrated a((onia solution,
Crea( precipitate of /gBr for(s,
Solid dissol)es,
Iodide -
+
Test 1
/dd concentrated sulphuric acid to the solid iodide,
1urple acidic fu(es are seen, .he
(i!ture turns to a bro#n slurr,
Test 2
/dd dilute nitric acid to a solution of a iodide to acidif the
solution, .his eli(inates an carbonates or sulphites,
/dd sil)er chloride to the solution,
/dd concentrated a((onia solution,
2ello# precipitate of /g- for(s,
Solid is insoluble,
itrate NO*
+
Test 1
%eat solid nitrate,
-f group 3 solid $not 'i& then #ill deco(pose to gi)e the
nitrite and o!gen,
/ll other solid nitrates deco(pose to gi)e the (etal o!ide,
nitrogen dio!ide and o!gen,
O!gen gas is e)ol)ed that #ill relight a
glo#ing splint,
Bro#n gas is seen $NO2&, O!gen gas is
also e)ol)ed and #ill relight a glo#ing
splint,
Test 2
Boil nitrate solution #ith alu(iniu(45e)arda6s allo, in
sodiu( hdro!ide solution,
.est )apour #ith red lit(us paper,
'it(us paper turns blue in the presence
of a((onia,
!mmonium N%4
+
.est
"arm ammonium compound #ith aOH$
Test vapours immediately using damp red litmus paper$
N%
*
turns the lit(us paper blue,
%ithium 'i
+
Test
5ip nichro(e #ire in %Cl,
5ip #ire in solid,
%eat #ire in centre of fla(e,
Obser)e colour of fla(e,
/ car(ine red fla(e is seen,
Sodium Na
+
Test
5ip nichro(e #ire in %Cl,
5ip #ire in solid,
%eat #ire in centre of fla(e,
Obser)e colour of fla(e,
/ ello# fla(e is seen,
&otassium 7
+
Test
5ip nichro(e #ire in %Cl,
5ip #ire in solid,
%eat #ire in centre of fla(e,
Obser)e colour of fla(e,
/ lilac fla(e is seen,
'agnesium Mg
2+
Test
/dd NaO% solution to the (agnesiu( solid,
/ #hite solid for(s #hich is insoluble
in e!cess NaO%$a8&, .his is
Mg$O%&2$s&
Calcium Ca
2+
Test / bric9 red fla(e is seen,
5ip nichro(e #ire in %Cl,
5ip #ire in solid,
%eat #ire in centre of fla(e,
Obser)e colour of fla(e,
Strontium Sr
2+
Test
5ip nichro(e #ire in %Cl,
5ip #ire in solid,
%eat #ire in centre of fla(e,
Obser)e colour of fla(e,
/ cri(son red fla(e is seen,
Barium Ba
2+
Test
5ip nichro(e #ire in %Cl,
5ip #ire in solid,
%eat #ire in centre of fla(e,
Obser)e colour of fla(e,
/ apple green fla(e is seen,
*ests
ame
Formu
la
Test Observations
Hydrogen %2 -gnite gas, S8uea9 pop is heard,
O(ygen O2
1lace a glo#ing splint in a sa(ple of the
gas,
.he glo#ing splint relights,
Carbon
dio(ide
CO2
Bubble gas through li(e#ater $saturated
solution of calciu( hdro!ide&
/ solution turns fro( colourless to cloud, / #hite $(il9&
precipitate of calciu( carbonate for(s #hich is sparingl
soluble,
!mmonia N%* .est for gas using da(p red lit(us paper, 'it(us paper turns blue,
Chlorine Cl2
Test 1
.est for gas using da(p lit(us paper $red or
blue&
Chlorine bleaches the lit(us paper )er 8uic9l,
Test 2
.est for gas using (oist starch+iodide paper,
.he paper turns blue+blac9,
Test )
1ass gas through a solution of a bro(ide,
.he solution turns fro( colourless to orange,
Test *
1ass gas through a solution of an iodide,
.he solution turns fro( colourless to bro#n $possibl #ith a
blac9 precipitate, iodine&,
itrogen
dio(ide
NO2 Not (an tests for this gas, .he gas is bro#n,
Sulphur
dio(ide
SO2
Test 1
Bubble gas through a solution of potassiu(
dichro(ate $0-& dissol)ed in sulphuric acid,
.he solution turns fro( orange to green,
Test 2
Bubble gas through a solution of potassiu(
(anganate $0--& dissol)ed in sulphuric acid,
.he solution turns fro( purple to colourless,
Aolumetric analysis
Aolumetric analysis +titration, involves the reaction beteen to solutions. @or one solution% both the
volume and the concentration are knonB for the other% the volume only is knon. Apparatus used
includes a burette% a pipette and a volumetric flask.
What is a standard solution?
A solution for hich concentration is accurately knon. *he concentration may have been found by a
previous titration or by eighing the solute and making a solution of knon volume. Such a solution is a
primary standard solution.
How is a 250cm3 standard solution prepared?
/ake sure that the balance is clean and dry. 0ipe it ith a damp cloth.
-lace the eighing bottle on the pan and tare the balance +i.e. re-Cero it,
*ake the bottle off the balance and add solid to it. *his ensures that no spillages fall on the pan.
0hen you have the re1uired amount% rite its value don immediately.
Deplace on balance% and if the re1uired amount is added% ithdra the mass.
0ash out a 2.:cm8 volumetric flask three times using pure ater.
*ransfer the solid to a 2.:cm8 volumetric flask using a funnel% and ash out the eighing bottle
into the flask through the funnel.
Add about "::cm8 of distilled ater to the flask.
Stir the solution using a glass rod.
0ash all remaining apparatus including the glass rod% funnel and transfer the rest of this to the
flask.
/ake up to 2.:cm8 ith distilled ater so that the bottom of the meniscus <ust touches the
2.:cm8 mark.
Stopper the flask.
Shake the flask vigorously and)or invert the flask . or E times to dissolve the solid.
Concentration of solution 9 mass of solid used)molar mass of solid x ":::)2.: +units moldm-8,
Using the pipette
A glass bulb pipette ill deliver the volume stated on it ithin acceptable limits only.
=sing a pipette filler% dra a little of the solution to be used into the pipette and use this to rinse
the pipette.
@ill the pipette to about 2-8cm8 above the mark. -ipette fillers are difficult to ad<ust accurately% so
1uickly remove the filler and close the pipette ith your forefinger +not thumb,. Delease the solution
until the bottom of the meniscus is on the mark.
Immediately transfer the pipette to the conical flask in hich you ill do the titration% and allo the
solution to dispense under gravity.
Using the burette
/aking sure that the tap is shut% add about ":-".cm8 of the appropriate solution to the burette
and rinse it out% not forgetting to open the tap and rinse the <et.
Close the tap and fill the burette. A small funnel should be used to add the solution but be careful
not to overfill the funnel.
Demove the funnel% because titrating ith a funnel in the burette can lead to serious error if a drop
of li1uid in the funnel stem falls into the burette during the titration.
(ring the meniscus on to the scale by opening the tap to allo solution to pass through the
burette. *here is no particular reason to bring the meniscus exactly to the Cero mark.
/ake sure that the burette is full to the tip of the <et.
After a suitable indicator has been added to the solution in the conical flask% sirl the flask under
the burette ith one hand hilst ad<usting the burette tap ith your other hand.
Add the solution in the burette to the conical flask sloly% sirling the flask all the time.
As the endpoint is approached% the indicator ill change colour more sloly. *he titrant should be
added drop by drop near to the endpoint.
Depeat the titration until you have three concordant titres% i.e. volumes that are similar. *his means
ithin :.2cm8 or better if you have been careful. *aking the mean of three tires that differ by "cm8 or
more is no guarantee of an accurate anser.
ommon indicators
/ethyl orange - yello in alkali% red in acid +orange at end point,
-henolphthalein - pink in alkali% colourless in acid.
6nthalpy change measurements
0eigh a spirit lamp +containing a li1uid alcohol, using a balance accurate to 8 decimal places.
Decord the mass measured.
=se a measuring cylinder to put ":: cm8 of distilled ater into a small beaker and clamps this at a
fixed height above the spirit lamp +about 2 cm,.
Decord the initial temperature of the ater using a thermometer.
>ight the lamp using a burning splint.
Heat the ater using the spirit lamp until the temperature has gone up by about ":C. Stir the
ater ith the thermometer the hole time.
-ut a cap on the spirit to stop the alcohol burning. *he lid stops also stops further evaporation of
the li1uid alcohol.
Deeigh the spirit lamp and record the mass.
Calculate the enthalpy change
Possible sources o! error
*here may be heat loss due to the apparatus used and heat may have dissipated through the
insulating material --5 should use a polystyrene cup and insulation like a lid.
*he specific heat capacity and density of ater are used +and not of HCl,.
*he masses of solid added to the acid are ignored.
It is assumed that the specific heat capacity of the polystyrene cup is negligible.
Some heat is lost hen the hydrogen or carbon dioxide are evolved in the reactions.
/any organic reactions are slo and re1uire prolonged heating
*o achieve this ithout loss of li1uid% reaction mixtures are heated in a flask carrying a vertical
condenser.
*his is heating under refluxB the solvent is condensed and returned to the flask% so the mixture can
be heated as long as desired.
*o heat the round bottomed flask% either use a ater bath% an oil bath or a heated plate mantle. A
(unsen burner isnFt really suitable.
Simple distillation
*o separate a volatile solvent from a mixture
Simple distillation is used here a volatile component has to be separated from a mixture% the
other components of the mixture being very much volatile or non-volatile.
*he mixture is heated.
*he fraction that boils is collected ithin the temperature range of the fraction. +normally " or 2
degrees before the boiling temperature,
*he condenser cools the fraction so it distils and is collected in the receiving flask.
@ractional distillation
*o separate mixtures of volatile li1uids.
De-crystallisation - =sed to purify a solid material by removing both soluble and insoluble
impurities. *he choice of solvent is important. *he substance must be easily soluble in the boiling
solvent and much less soluble at room temperature. *his ensures the smallest possible loss of
material% although some loss is inevitable ith this techni1ue.
"e#crystallisation method
3, &issolve the solid in the minimum amount of boiling solvent. *his ensures that the solution is
saturated ith respect to the main solute but not ith respect to the impurities% hich are present
in much smaller amounts.
2, @ilter the hot mixture through a preheated filter funnel. *his removes insoluble impurities. *he hot
funnel is necessary to prevent the solute crystallising and blocking the funnel. @iltration under
vacuum using a (uchner funnel is often preferred% because it is fast.
*, Cool the hot filtrate% either to room temperature or% if necessary% in a bath of iced ater. Dapid
cooling gives small crystals% slo cooling large ones. *he large crystals are often less pure.
4, @ilter the cold mixture using a (uchner funnel.
:, 0ash the crystals ith a small amount of cold solvent. *his removes any impurity remaining on the
surface of the crystals. A small amount of cold solvent is used so that the crystals arenFt ashed
aay ) donFt dissolve.
;, Suck the crystals as dry as possible on the filter.
<, *ransfer the crystals to a desiccator to dry. &rying beteen filter paper is sometimes
recommended% but it is a very poor method.
/elting point determination
*his is used to determine the purity of the re-crystallisation solid. -lace small amount of the solid in the
sealed end of a capillary tube. -lace in the melting point apparatus. A sharp melting point over a small
range shos purity% hen compared ith the set-book value of a higher melting point% that indicates an
impure solid.
$rganic tests
Collect ": cmG of the samples.
*est the samples in the folloing order
Alkenes ? bromine ater --5 decolourises --5 alkene
Alcohols ? Spatula of solid -Cl.. *est fumes ith damp litmus paper --5 litmus redH 0hite fumes
near ammoniaH --5 alcohol
Halogenoalkane ? Add #a$H% ethanol as solvent. Shake and arm for 8 minutes. Cool and add
nitric acid I silver nitrate. --5 hite 9 chlorideB cream 9 bromideB yello 9 iodide. --5 Confirm ith
ammonia
Alkane% the substance left is the alkane.
*echni1ues
Separating insoluble impurities +rom a soluble substance $=e(o)ing sand and i(purities fro( salt solution&
Separating a mi(ture o+ immiscible li,uids $Separating a (i!ture of #ater and he!ane&
Water and he!ane are i((iscible for(ing 2 separate laers and are separated using a separating +unnel
Separating a solvent +rom solution Simple distillation
Separating a li,uid +rom a mi(ture o+ miscible li,uids
Fractional distillation Separates (i!tures of (iscible li8uids #ith different Bt6s, using a fractionating colu(n increasing
efficienc of redistillation process, pac9ed #ith inert (aterial$glass beads& increasing surface area #here )apour (a condense,
+ When (i!ture is boiled )apours of (ost )olatile co(ponent$lo#est Bt& rises into the )ertical colu(n #here the condense to
li8uids,
+ /s the descend the are reheated to Bt b the hotter rising )apours of the ne!t co(ponent,
+ Boiling condensing process occurs repeatedl inside the colu(n so there is a te(perature gradient,
+ 0apours of the (ore )olatile co(ponents reach the top of the colu(n and enter the condenser for collection
Boiling under re+lu( Where reagents )olatile
+ condenses )apours and returns reagents to flas9, pre)ents loss of
reactants4products, prolonged heating for slo# reactions
+ "or preparation of aldehde4carbo!lic acid fro( alcohol
$3&=eason for heating the (i!ture but then ta9ing the fla(e a#a
$3&pro)ide Ea, e!other(ic4pre)ent reaction getting out of control
Separating mi(tures o+ similar compounds in solution $Separating des present in a sa(ple of in9&
Chro(atogra( Chromatography 5ifferent co(ponents of the de spread out at different rates
>sing a s8uare sheet of filter paper, spots of de solutions are put along the baseline
.he filter paper is coiled into a clinder and placed in a tan9 containing a s(all )olu(e of sol)ent
.he lid is replaced on the tan9, sol)ent rises up the filter paper
When the sol)ent nearl reaches the top of the filter paper, the filter paper is re(o)ed and position
of sol)ent (ar9ed,
5es / ? B are either pure substances or a (i!ture of des not separated #ith the sol)ent used
5e C is co(posed of / ? B as the spots correspond
Colourless substances can be separated and seen b spraing4dipping the filter paper into a
locating agent #hich colours the spots produced


Separating a solid #hich sublimes- +rom a solid #hich doesn.t sublime
Gi)en a (i!ture of /((oniu( chloride$subli(es& and sodiu( chloride$doesn6t subli(e&
%eat the (i!ture, /((oniu( chloride turns directl to )apour but the sodiu( chloride re(ains unchanged
When the )apour is cooled solid a((oniu( chloride collects free fro( sodiu( chloride
/ pure substance has a definite Mt, presence of i(purities causes the substance to (elt o)er a range of te(peratures
Best (ethod of separation of $3& Oil and #ater $2& /lcohol and #ater $*& Nitrogen fro( li8uid air
$3& Separating funnel$2& "ractional distillation $*& "ractional distillation
'i(ture Compound
+ 1roportions of the different ele(ents can be )aried
+ 1roperties are those of the ele(ents (a9ing it up
+ Ele(ents can be separated b si(ple (ethods
+ No energ gained or lost #hen the (i!ture is (ade
+ 5ifferent ele(ents ha)e to be present in fi!ed proportions
+ 1roperties different fro( properties of ele(ents (a9ing it up
+ 5ifficult to separate into the ele(ents #hich (a9e it up
+ Energ usuall gi)en out4ta9en in #hen co(pound is for(ed
Sub/atomic particles 1rotons, neutrons and electrons #hich (a9es up the ato(
&article /n ato(, (olecule, ion, electron or an identifiable particle 0T& =oo( te(perature and pressure
1lectron / negati)el charged particle, #ith negligible (ass occuping the outer regions of all ato(s
Immiscible >nable to (i!, dissol)e in each other, to for( a ho(ogenous (i!ture 'iscible Soluble in each other
2a,3 Substance dissol)ed in #ater to for( an a8ueous solution
State symbols 1hsical state of the reactants at =. !,ueous2a,3
Solvent Substance in #hich other substances are dissol)ed
Solute Substance dissol)ed in another substance$sol)ent&to for( a solution
Chemical species Collection of particles 4istilled #ater Water that has been purified b distillation
Ion When nu(ber of protons and electrons are different
!tom .he s(allest part of an ele(ent that can e!ist on its o#n
'olecule 2 or (ore ato(s bonded together
1lement / pure substance #hich can6t be split up b che(ical
reaction
Compound Co(bination of ele(ents in fi!ed proportions )ia
snthesis
-n for(ation of a co(pound fro( ions the charges balance out
1hsical properties@ Mt, Bt, hardness
A Co(pounds ending in 5ate 5ite contain o!gen, greater proportion of o!gen in the co(pound ending in Bate
Sodiu( sulphate Na2SO4 Sodiu( sulphite Na2SO*
A Co(pounds #ith prefi! per5 contain e!tra o!gen
Sodiu( o!ide Na2O Sodiu( pero!ide Na2O2
A Co(pounds #ith prefi! thio5 contain a sulphur ato( in place of an o!gen ato(
Sodiu( sulphate Na2SO4 Sodiu( thiosulphate Na2S2O*
'etalloid Ele(ent #hich has properties bet#een (etals and non(etals
+ -ons in an ionic co(pound are tightl held together in a regular lattice, lattice energ is re8uired to brea9 it up and (elt the substance
/ (etal high in the reacti)it series has stable ores and the (etal can be obtained onl b electrolsis
/ (etal (iddle in the reacti)it series doesn6t for( stable ores and can be e!tracted b reduction reactions $often #ith carbon&
/ (etal lo# in the reacti)it series, if present in unstable ores can be e!tracted b heating
4ecomposition Splitting up of a co(pound $.her(al deco(position + deco(position of a co(pound b heating&
Combustion is the reaction of a substance #ith o!gen, total (ass of products is greater than the (ass of the substance burned,
difference being the (ass of o!gen co(bined
Sublimation of an ele(ent4co(pound is a transition fro( solid to gas #ith no inter(ediate stage
When a change of state ta9es place the te(perature re(ains constant despite a continuing suppl of energ, 'atent heat is the energ
#hich is not being used to raise the te(perature and supplies particles #ith the e!tra energ the re8uire as the state changes$gi)en out
#hen the re)erse changes ta9e place&
"e$s& + CuSO4$a8& "eSO4$a8& + Cu$s& Blue solution turns colourless and bro#n copper is deposited
/ displace(ent reaction #here a (ore reacti)e (etal replaces a less reacti)e (etal in a co(pound
Electrolsis of %Cl$a8&@ 2%Cl$a8& Cl2$g& + %2$g& Cathode@ 2%
+
$a8& + 2e
B
%2$g& /node@ 2Cl
B
$a8&Cl2$g&+2e
B
%eat
/((oniu( chloride N%4Cl$s& N%*$g& + %Cl$g&
Cool
/ stopper fro( a bottle of $conc&N%*$a8& held near a stopper fro( a bottle of $conc&%Cl acid gi)es a dense #hite s(o9e of N%4Cl
Synthetic &ath#ays$Series of reactions built up to con)ert one functional group into another&
A =eactions of functional groups assu(ed to be the sa(e #hether (olecules are si(ple or co(plicated
A Snthesis of the product (olecule possible because in an reaction of a functional group a product is for(ed capable of con)ersion
into other (olecules
H C
$g& used of (ass
D. 4,3E :,*3 B
6

9F (ol
B3
Would the result for H be (ore accurate if the te(perature of the solution #ere 9no#n to *dpG
2es, te(perature #ould then be 9no#n to a co(parable precision to the other factors in the e8uation
1lan an e!peri(ent to in)estigate concentration on rate of a reaction Mg$s& + 2%Cl$a8& MgCl
2
$a8& + %
2
$g&
A /pparatus diagra(4description4addition of Mg to acid in appropriate container
A Weigh Mg4cut (easured length and (easure )olu(e of acid- (easure )olu(e of %
2
#ith ti(e4ti(e ho# long it ta9es for Mg to
6dissol)e6 A repeat #ith different concentration$s& %Cl A repeat #ith sa(e (ass4length Mg and sa(e )olu(e %Cl
A one a!is labelled concentration4)olu(e %
2
and other a!is ti(e4t a!is changed to 34t
if (easured )olu(e %
2
at least t#o cur)es sho#ing increasing rate #ith conc
if (easured ti(e to dissol)e Mg one line sho#ing ti(e decreasing #ith conc or 34t increasing #ith conc
A /cid irritant so #ear glo)es or hdrogen e!plosi)e + no na9ed fla(e or Build up of pressure in sringe + attach plunger #ith string
$N%
4
&
2
CO
*
reacts #ith both 3(old(
B
H$dil&%NO
*
and 3(old(
B
H$dil&7O% in the ratio 3@2
5e)ise an e!peri(ent to deter(ine #hich of the t#o reactions is the (ore e!other(ic
A 1repare solutions of 9no#n concentration of the solid
A Suggestion of apparatus used e,g, lagged calori(eter or lo# (ass polstrene cup A >se sa(e )olu(e of each solution
A Measure (a!i(u( te(perature change A -(pro)e reliabilit of results, repeat e!peri(ent A 1ossible sources of error identified
A =eaction #ith the greater te(perature change is the (ore e!other(ic A Since a((onia e)ol)ed use a fu(e cupboard
M C Group 3 M
2
CO
*
$s& + 2%Cl$a8& 2MCl$a8&+CO
2
$g&+%
2
O$l&
1lan an e!peri(ent, results of #hich used to calculate the relati)e
(olecular (ass of the carbonate and identif M
/t te(p of e!peri(ent 3 (ole of CO
2
occupies a )olu(e of 24d(
*
=elati)e ato(ic (ass@ 'i C <, C C 32, O C 3;, Na C 2*, 7 C *I, =b C E:,
Cs C 3**
G a s s r i n g e
A /dd M
2
CO
*
+ acid and stopper flas94use suspended test tube in large flas9
A Mass of M
2
CO
*
and $final&)ol of CO
2
4#hen effer)escence stops record )olu(e of gas in sringe
A E!plain con)ersion )olu(e of CO
2
to (oles b correct use of 24
A >se of (oles M
2
CO
*
C (ass M
2
CO
*
J M
r
M
2
CO
*
to find M
r
A %ence find identit of M
A Escape of gas before bung replaced4solid did not all react4CO
2
soluble in acid A Ee protection+acid haKard
A Should not affect identification since e)en if M
r
is slightl #rong it #ill still correspond to nearest Group 3 (etal ato(ic (ass
1lan an e!peri(ent to identif an acidic co(pound, (olar (ass for an acid esti(ated to be EE L 2 g (ol
B3

What si(ple test #ould allo# butenoic acid to be distinguished fro( the other t#oG 5e)ise a plan based upon a 8uantitati)e
e!peri(ent that #ould allo# the other t#o to be distinguished
C%
2
C C% C%
2
COO% E; g (ol
B3

* structures proposed for this acid
C%
*
C%
2
C%
2
COO% EE g (ol
B3

%
C O O %
C O O % IM g (ol
B3
/l9ene detected using bro(ine #ater, onl 3 #ould sho# decolourisation
"i!ed (ass of acid, Standard na(ed al9ali, Controlled (ethod of addition, .o an identified end point of a na(ed suitable indicator,
Calculation of (ole ratio
$3&/ sa(ple of NaCl #as thought to contain an i(purit of Ba$NO*&2 / student suggested a fla(e test
$a&$i&Suggest #h a fla(e test on the (i!ture #ould not be a satisfactor #a of detecting the presence of bariu( ions in the sa(ple
$i& A ello#4stronger4persistent Na fla(e A Obscures4Ba fla(e NOT N(a9es it difficult to distinguish bet#een the t#o coloursO
$ii&Suggest a reagent that could be used to produce a ppt of a bariu( co(pound fro( a solution of the sa(ple
$ii& A $conc&%
2
SO
4
$solution& of an soluble sulphate $MgSO
4
, $N%
4
&2SO
4
, Na
2
SO
4
&
$2&$a&P$has O% group&decolourised cold potassiu( (anganate$0--& acidified #ith $dil&%
2
SO
4
acid, structure of P suggested b thisG
$a&carbon double bond
$b&Co(plete o!idation of P #ith potassiu( dichro(ate$0-& solution and $dil&%2SO4 acid produces 2 C
4
%
;
O structure for 2G
$b&
% % %
C C % C C % C C O % C C %
% % O
2 *
2 1 3
$c&Structural for(ula for PG$c&
% % % %
C C C % C
% % O %
2 2 3
P (ust be a secondar alcohol because 9etone for(ed on o!idation carbo!lic acid is not for(ed
$*&$a&Write an ionic e8uation for the hdrolsis of 3+bro(obutane b #ater $a&C%
4
%
I
Br + %
2
O C
4
%
I
O% + %
+
+ Br
B
$b&Suggest #h ethanol #as used in the e!peri(ent $b&Sol)ent4sil)er nitrate solution in #ater and bro(obutane i((iscible
$c&Suggest a reason for the use of a #ater bath $c&=eaction slo# at =.4increases rate4fla((able
$4&5escribe tests ou #ould use to distinguish bet#een the follo#ing pairs of co(pounds including results
$a&NaNO
*
and a((oniu( nitrate N%
4
NO
*
$a& "la(e test, sodiu( salt gi)es ello# colour- a((oniu( salt gi)es no colour
$:&$a&3+bro(obutane Bt3M2 QC (a be prepared b the reaction C
4
%
I
O% + NaBr + %
2
SO
4
C
4
%
I
Br + Na%SO
4
+ %
2
O
$a&5escribe ho# ou #ould use distillation apparatus to gi)e a sa(ple of pure 3+bro(obutane
$a&%eat (i!ture$slo#l&, collect onl distillate produced at around 3M2 C at Bt of 3+bro(obutane
$b&Suggest 2 reasons #h the actual ield #as (uch lo#er than the (a! ield
$b&side reactions, reaction inco(plete, product lost in purification4transfers
$;&CaCO
*
$s& + 2%Cl$a8& CaCl
2
$a8& + %
2
O$l& + CO
2
$g&
E!peri(ent CaCO
*
%Cl acid
3 =. S(all pieces
:Mc(
*
of 3(old(
B*
2 S(all pieces
:Mc(
*
of 3(old(
B*
heated to
EMQC
* =. One large
piece
:Mc(
*
of 3(old(
B*
4 =. S(all pieces
:Mc(
*
of 2(old(
B*
$a&$i&E!plain #h there is a loss in (ass as the reaction proceeds
$i&CO
2
$g& e)ol)ed
$ii&E!plain the shape of the cur)e dra#n for E!peri(ent 3
$ii&=eaction$fast at first then&slo#s do#n4gi)es off less CO
2
per
(in #hen line is horiKontal, the reaction has finished4after ; or <
(inutes4#hen 3 g of CO
2
lost
2 , M M
3 , : M
3 , M M
M , : M
: 3 M 3 :
. i ( e 4 ( i n
E ! p t , 3
M
a
s
s

l
o
s
s
4
g
=esults of E!peri(ent 3
$b&5ra# cur)es on the graph to represent the results ou #ould e!pect for E!peri(ents 2, * and 4, 'abel the cur)es 2, * and 4
$b&E!peri(ent 2 steeper than 3 and sa(e (ass loss E!peri(ent * less steep than 3 and sa(e (ass loss4reaction inco(plete
E!peri(ent 4 steeper than 3 and horiKontal at t#ice (ass loss
$<&Suggest one appropriate safet precaution that should be ta9en as ethanedioic acid is to!ic $<&Safet pipette filler
$E&-n an e!peri(ent to find , Kinc CuSO4$a8& in a plastic cup Rn$s& + Cu
2+
$a8& Rn
2+
$a8& + Cu$s&
Suggest reasons #h a series of te(p readings is ta9en rather than si(pl initial and final readings
$E& Reason 1 /n fluctuations in te(perature s(oothed out 4 (ini(ises reading error4allo#s line of best fit to be dra#n
Reason 2 /ble to allo# for cooling effect4able to calculate (ore accurate te(perature change4need to find highest te(perature

Another *est >ist +If you find above one hard to read,
Flame test
3 Clean end of platinu(4nichro(e #ire #ith$conc&%Cl, burning off i(purities in a roaring bunsen fla(e until there6s no persistent fla(e colouration
2 Moisten the end of the clean #ire #ith $conc&%Cl and then dip into the sa(ple to be tested
* %old the sa(ple at the edge of a roaring bunsen fla(e
'ithiu( Car(ine red Calciu( Bric9 red
Sodiu( 2ello# Strontiu( Cri(son
1otassiu( 'ilac Bariu( /pple green
6as Test
/((onia N%* 1ungent s(ell, Moist lit(us paper red blue, $conc&%Cl at (outh of bottle, #hite s(o9e for(s
Carbon dio!ide CO2 1ass through li(e #ater, turning li(e #ater (il9
CaCO)2s3 7 H2O2l3 7 CO22g3 Ca2HCO)322a,3
'i(e#ater CO2 test Ca2OH322a,3 7 CO22g3 CaCO)2s3 White ppt 7 H2O2l3
Chlorine Cl2 S#i((ing pool s(ell, (oist lit(us paper blue red bleached
%drogen %2 'ighted splint, burns #ith s8uea9 pop
%drogen chloride %Cl Moist lit(us paper blue red
Nitrogen$-0&o!ide NO2 Bro#n gas, acrid s(ell, (oist lit(us paper blue red
O!gen O2 Glo#ing splint, relights
Water )apour %2O
White anhdrous copper$--& sulphate #hite blue CuSO4$s& + :%2O$l& CuSO4,:%2O$s&
Or dr blue cobalt chloride paper blue pin9
Sulphur dio!ide SO2 /crid s(ell, (oist lit(us paper blue red
Or potassiu( dichro(ate$0-& solution4paper fro( orange green
Cation Test !dd aOH2a,3 !dd H*OH2a,3
/((oniu( N%4
+
A %eat, a((onia e)ol)ed, (oist lit(us paper red blue
%
+
A Moist lit(us paper blue red
A /dd a carbonate, pass gas through li(e #ater, CO2 e)ol)ed turning li(e #ater (il9
Copper$--& Cu
2+
A / little, blue ppt for(s
A -n e!cess, insoluble
A / little, blue ppt for(s
A -n e!cess, dissol)es and a dar9 blue solution for(s
-ron$--& "e
2+
A / little, green ppt for(s A / little, green ppt for(s
A -n e!cess, insoluble A -n e!cess, insoluble
-ron$---& "e
*+
A / little, bro#n ppt for(s
A -n e!cess, insoluble
A / little, bro#n ppt for(s
A -n e!cess, insoluble
Calciu( Ca
2+
Magnesiu( Mg
2+
A / little, (il9 suspension for(s
A -n e!cess, insoluble
A / little, (il9 suspension for(s
A -n e!cess, insoluble
5istinguish Mg fro( Ca through fla(e test
A / little, (il9 suspension for(s
A -n e!cess, insoluble
A / little, (il9 suspension for(s
A -n e!cess, insoluble
/lu(iniu( /l
*+
'ead 1b
2+
A / little, #hite ppt for(s
A -n e!cess, dissol)es gi)ing colourless solution
A / little, #hite ppt for(s
A -n e!cess, insoluble
No ppt #ith $dil&%2SO44cold$dil&%Cl4$dil&7-4$dil&Na2S Sodiu( sulphide
A / little, #hite ppt for(s
A -n e!cess, dissol)es gi)ing colourless solution
A / little, #hite ppt for(s
A -n e!cess, insoluble
White ppt #ith $dil&%2SO4 White ppt #ith cold$dil&%Cl
2ello# ppt #ith $dil&7- Blac9 ppt #ith $dil&Na2S Sodiu( sulphide
Rinc Rn
2+
A / little, #hite ppt for(s
A -n e!cess, dissol)es gi)ing colourless solution
A / little, #hite ppt for(s
A -n e!cess, dissol)es gi)ing colourless solution
!nion Test
Carbonate p%S3M CO*
2B
uni)ersal indicator
/dd $dil&%Cl$a8& 1ass gas through li(e #ater, CO2 e)ol)ed turning li(e #ater (il9
Or add group -- ions, #hite ppt or heat4add boiling #ater, no gas e)ol)ed
%drogen carbonate %CO*
B
p% E+I
/dd $dil&%Cl$a8& 1ass gas through li(e #ater, CO2 e)ol)ed turning li(e #ater (il9
Or add (etal ions no ppt but heating causes #hite ppt to for( or %eat4add boiling #ater, CO2 e)ol)ed
Chloride Cl
B
/cidif #ith $dil&%NO*$a8& /dd /gNO*$a8& /dd $dil&N%* to ppt
White ppt /gCl for(s 1pt dissol)es lea)ing colourless solution
Bro(ide Br
B
/cidif #ith $dil&%NO*$a8& /dd /gNO*$a8& /dd $conc&N%* to ppt
Crea( ppt /gBr for(s 1pt dissol)es lea)ing colourless solution
-odide -
B
/cidif #ith $dil&%NO*$a8& /dd /gNO*$a8& /dd $conc&N%* to ppt
2ello# ppt /gBr for(s 1pt insoluble
Nitrate NO*
B
/dd NaO%$a8& /dd 5e)arda6s allo $po#dered Rn, /l& %eat ? hold (oist red lit(us at (outh of test tube
N%* e)ol)ed, lit(us paper red blue
Sulphate SO4
2B
/dd Bariu( nitrate Ba$NO*&2$a8&4chloride BaCl2$a8& /dd %Cl$a8&
White ppt -nsoluble
Sulphite SO*
2B
/dd Bariu( nitrate Ba$NO*&2$a8&4chloride BaCl2$a8& /dd %Cl$a8&
White ppt 5issol)es
Or add $dil&%Cl$a8& %eat
SO2 e)ol)ed turning potassiu( dichro(ate$0-& solution4paper fro( orange green
-ractical >ist
". /ake a salt and calculate the percentage yield +hydrated nickel sulfate,
2. make a salt and calculate the percentage yield +ammonium iron+II, sulfate,
8. carry out and interpret results of simple test tube reactions
4. measuring some enthalpy changes
.. finding the enthalpy of combustion of an alcohol
E. finding an enthalpy change that cannot be measured directly
3. reaction of alkanes
J. reaction of alkenes
K. experiment to find the effect of electrostatic force on <ets of li1uid
":. solubility of simple molecules in different solvents
"". thermal decomposition of group 2 nitrates and carbonates
"2. flame tests on compounds of group " and 2
"8. simple acid-base titrations
"4. oxidation of metal and non-metallic elements and ions by halogens
".. disproportion reactions ith cold and hot alkali
"E. iodine)thiosulfate titration and the determination of purity of potassium iodate+A,
"3. reactions beteen halogens and halide ions)some reactions of the halides
"J. factors that influence the rate of chemical reactions
"K. effect of temperature% pressure and concentrations on e1uilibrium
2:. reactions of alcohols
2". preparation of organic li1uid +reflux and distillation,
22. preparation of a halogenoalkane from an alcohol
28. reactions of the halogenoalkanes.