ECTION ONE - CLASSIFYING MATERIALS 1

Solids, Liquids and GasesThese are known as the fhree sfafes of maHer. Make sure you know everything there is to know.

I Solids have Strong Forces of Attraction I1) There are sfrong forces of aHracfion between molecules.2) The molecules are held in fixed positions in a very regular

laHice arrangemenf.3) They don'f move from their positions, so all solids keep a

definife shape and volume, and don't flow like liquids.4) They vibrafe about their positions.

The hoHer the solid becomes, the more they vibrafe.This causes solids to expand slightly when heated.

5) Solids can'f be compressed easily because the moleculesare already packed very closely fogefher.

6) Solids are generally very dense.

Ii uids have Moderate Forces of Attraction I1) There is some 1'0 ce of aHracflon between the molecules. 02) The molecules are free fo move past each other, but they 0 oOcgs

do tend to sfick fogefher. 0 03) liquids don' keep a definite shape and willflow to fill fhe 0 (9 0

boffom of a container. But they do keep the same volume. 0 0 004) The molecules are consfanfly moving in random mofion. 0 0 00

The hoffer the liquid becomes, the fasfer they move. 0 0This causes liquids to expand slightly when heated. 8CQcq 00

5) liquids can'f be compressed because the molecules are 0 000already packed closely fogefhe •

6) liquids are quite ense, but not as dense as solids.

Gases have No Forces of Attraction

o~--;;;;07'

Ivo 30Pressure exerted blJ molecules bouncingoff the walls of the container.

1) There is no force of affracfion between the molecules.2) The molecules are free fo move. They travel in sfraighf

lines and only interact with each other when fhey collide.3) Gases don'f keep a definite shape or volume and willalways

expand fo fill any container. Gases exert a pressure on thewalls of the container.

4) The molecules are consfanfly moving in random mofion.The hoHer the gas becomes, the fasfer they move.heafed, a gas willeither expand or its pressure will!lin!Q!1~~

5) Gases can be compressed easily because ther-g's afree space between the molecules.

6) Gases all have very low densifies.

Don't ggfyourself in a state about this lot iusThis is prett\:l basic stuff. but people still lose marks in the Exam becausethe little details reall\:l thoroughl\:l' And there's onl\:l one wa\:l to do that:SCRIBBLE IT ALL DOWN FROM MEMORY. That soon sno s\:l0u've got to do for ever\:l p"8ge. Do H no fa

Changes of stateCHANGES OF STATE alwaysinvolveHEAT ENERGY going either IN or OUT.

o

Melting - the rigid lattice breaks down1}When a 90LlD is heated. the heat

energy goes to the molecules.

2) It makes them vibrate more andmore.

3) Eventually the strong forcesbetween the molecules (that holdthem in the rigid lattice) areovercome. and the moleculesstart to move around. The solidhas now MELTED.

Evaporation - the fastest molecules esca e IQv. ~

1}When a LIQUID is heated. theheat energy goes to Jrhe 0 0 0molecules. which makes them 0 0 0 0 ~0 0 ~move faster. ~ ~ ~ \§ -4!J ~ ~

~ g 0 ~2) 90me molecules move faster 0a 00 0 go 0 0

than others do. ~ ~ ~ IJ!J ~ -4!J ~ =f!!; @

3) Fast-moving molecules at the surface will overcome the forces of attraction from the othermolecules and escape. This is EVAPORATION.

Boiling - all molecules are fast enough to esca~

~ ~~O~ ~~Q O~ ((OOIQO aJIO~ ~O ~ ~~ 2fI!!)&~C~~ ~O OJl0))) 0)))

1} When the liquid gets hofenough. virtually all themolecules have enoughspeed and energy toovercome the forces anescape each other.

2) At this point big bubbles of gas form inside the liquid as the molecules break away from ~other. This is BOILING.

Simmer down - this stuffrs reallJ!..1luite eaSlkThere are three diagrams and just eight numbered points on this page. Tyou didn't need to learn them. 90 learn them. Then cover the page a dYou have to realise this is the only way to really learn stuff properly.

SECTION ONE - CLASSIFYING MATERIALS

Changes of State

I Heating and Cooling Graphs Have Jmportant Flat Spots I1) When a substance is MELTING or BOILING, all the heat energ,y supplied is used for breaking,

bonds rather than raising the temperature, hence the flat spots in the heating graph shownhere.

Temperature

I Heating I

Boilin~Point Iboiling I

2) As the molecules meltinto liquid, or boil intogas, HEAT 19 TAKEN IN asthe bonds are broken.

ImeltingI3) This means the

temperature won't g,o upuntil a/l the substance hasturned to liquid or gas.

Isolid I Time

4) When a substance is being oooled, the graph for temperature will show a flat spot where itoondenses from g,as back into liquid and also at the freezing, point where it changes backfrom liquid into solid.

Temperature5) As the molecules

oondense back intoliquid or fuse into asolid, HEAT 19 GIVENOUT as the bonds form.

I Cooling I

BoilingPoinf

Icondensing

B) This means thetemperature won't g,odown until a/l thesubstance has turnedto liquid or solid.

MeltingPoint

liquid

Revision - don't get all steamed up about it. ••They can give you graphs just like these in the Exam and likely as not they'll ask you to explainthe flat spots. Remember, it's all to do with the heat energy getting soaked up when bonds arebeing broken, and then being released again when the bonds are re-forming. Learn and enjoy.

SECTION ONE - CLASSIFYING MATERIALS

Electron Shells and Ionic BondingThe fact Jhat electrons occupy "shells" around the nucleus is what causes the whole of chemistry.Remember that I and watch how it applies to each bit of it. It's ace.

3rd shell still filling

A shell with just one electron is well keen to get rid ...1) All the atorns over at the left hand side of the periodic table, such as sodium, potassium,

oaloium etc. have just one or two eleotrons in their outer shell.2) And basically they're pretty keen to get shot of them, because then

they'll only have full shells left, which is how they like it.3) 90 given half a chance they do get rid, and that leaves the atorn as

an ION instead.4) Now ions aren't the kind of things that sit around quietly watching

the world go by.5) They tend to leap at the first passing ion with an opposite oharge

and stick to it likeglue.

I A nearly full shell is well keen to get that extra electron... I1) On the other side of the periodic table, the elernents in Group 9ix and Group geven, such as

oxygen and ohlorine have outer shells which are nearly full.2) The\:l'reobviously pretty keen to gain that extra one or two

eleotrons to fill the shell up.3) When the\:l do of course the\:l becorne ION9, you know, not the

. d of things to sit around, and before you know it, POP, they'veed onto the atorn (ion) that gave up the electron a rnornent

e eaction of sodium and ohlorine is a oIassio oase ase ext page:

- 't's the name of the game, pal ...is page but onl\:lto harnrner horne two very basic points:es.

e like to gain thern. LEARN ALL THE HIGHLIGHTED BI

tlERLiL5

Ionic Bonding and Covalent BondingIn IONIC BONDING, atoms lose or gain electrons to form charged particles (ions) which are then stronglyaHracted to one another (the attraction of opposite charges, + and -).In COVALENT BONDING electrons are shared, not swapped.

Ionic Bonding - Swa ing Electrons I

1) lonio bonding is easy to understand.2) Eleofrons jump from one one atom to another and they both end up with full eleofron shells.3) They then get affraofed to each other because they have opposite oharges.

1) The sodium atomgives up its oufereleofron andbecomes an Na+ ion.

2) The ohlorine atompioks up the spareeleofron andbecomes a CI- ion.

3) Then,

before you POP'know it... •

I Covalent Bonds - Sharing Electrons I1) Somefimes atoms prefer to make COVALENT BONDS by sharing eleofrons with other atoms.2) This way bofh afoms feel that they have a full oufer shell, and that makes them happy.3) Eaoh oovalenf bond provides one exfra shared eleofron for each atom.4) Each atom involved has to make enough oovalenf bonds to fill up its outer shell.

IllYdrogen Molecule, H2 I Water Molecule, HJl/t!..~

Shared '~+electrons I. / f @

~O

~~

® x~

•x

Full Shells - vou just can't beat them ...LEARN the diagram for the formation of ionic bonds, with its three ste •LEARN the four numbered points about covalent bonds and the 0

Then turn over and scribble it all down again. AIl from e

SECllO_ -

Elements, Compounds and MixturesYou'd better be sure you know the subfle difference between these.

Elements consist of one tyjJe of atom onlyQuite a lot pf everyday substances are elem ,

Co per Aluminium Iron

I Mixtures are easily separated I1) Air is a mixture of gases.

The oxygen. nitrogen. argon and carbon dioxide can all be separated out quite easily.2) There is no chemical bond between the different parts of a mixture.3) The properties of a mixture are just a mixture of the properties of the separate parts.4) A mixture of iron powder and sulphur powder will show the properties of both iron and

sulphur. It will contain grey magnetic bits of iron and bright yellow bits of sulphur.

Air is amixtureof gases

Argonatom

Iron and sulphur mixedtogether. but unreacted

Com ounds are chemically bonded I1) Carbon dioxide is a compound formed from a chemical reaction between carbon and oxygen.2) It's vert; difficult to separate the two original elements out again.3) The properties of a compound are totallt; different from the properties of the originalelements.4) If iron and sulphur react to form iron sulphide. the compound formed is a grey solid lump.

and doesn't behave anything like either iron or sulphur.

~!

®+® [ • ~Fe9Mixture Compound

+O~oC + ~ c:=:=> ~ CO2

Don't mix these up - it'll only compound your problems ••,Elements, mixtures and compounds. To most people they sound like basically the same thing.Hal Not to GC9E Examiners the\:j don't, pal! You make mighty sure you remember theirdifferent names and the differences between them. Just more easy marks to be won or lost.

SECTION ONE - CLASSIFYL\G MATERIALS

Common Tests and Hazard Symb•You need to know these FIVE EA9Y LAB TE9T9:

11) Chlorine bleaches damp litmus paper I(i.e. it turns it white).

Damp litmuspaper

12) Oxvgen relights a glowing splint IThe standard test for ox~en is that it relights a glowing splint.

13) Carbon dioxide turns limewater milky ICarbon dioxide can be detected by its turninglimewater oloudy when it's bubbled through it.

14) The three lab tests for Water IWater can be detected in three ways:

a) by its boilingpoint of 100°Cb) by turning white anhydrous oopper sulphate to

blue hydrated oopper sulphate (and getting hot)c) by turning anhydrous oobalt ohloride paper from blue to pink.

~

)

b . ~~~~%~c::4>~ater

~

Blue cobaltc)----_ chloride

Water~l~~ paper

IS) Lab test for Hydrogen - the notorious "Squeakypop" IJust bring a lighted splint near the gas with air around. Squoe;~If it's hydrogen it'll make a "squeaky pop" as it burns

with the oxygen in the air to form H20.

Hazard Sym_b_ol_s

[eJ OxidisingProvides ox~en which allows othermaterials to burn more fieroely.EXAMPLE: Liquid oxygen.

Highly FlammableCatohes fire easily.EXAMPLE: Petrol.

00 Toxic §]Can oause death either by swallowing, ~.:I breathing in. or absorption through the ..:.. ••skin. EXAMPLE: Cyanide.

The official hazard symbol for "harmful"and "irritant" is a black cross. 90me products

add an "h"or "i"to show the difference.

HarmfulSimilar to toxic but not quite asdangerous.EXAMPLE: Petrol. meths.

IrritantNot corrosive but oan oausereddening or blistering of the skin.EXAMPLE9: Bleach, children, etc.

CorrosiveAttaoks and destroy§ livinetissues, including eyes and •EXAMPLE: Bulphuric. acid.

learn the Five lab Tests - easy as squeak~This is pretty basic stuff, but people still lose marks in the Exam because they do 'the little details really thoroughly. That's true for just about everything iletting your eyes drift lazily across the page and thinking "Oh yeah, lreally make sure you do know it all. And fhere's on/lJ one 8lJ·0

Uses of The Three Common Metals

I Iron is made into steel which is cheap and strong IIRON AND STEEL: ~I

ADVANTAGE9: Cheap and strong. ==================;================DI9AD~ANTAGE9: Heavy, and prone to rusting away. ~

Iron and steel are used for:1) Construction such as bridses and buildinss. cn~ ~2) NCOarTspaLAndNlEoSrriesdandthrabinksanddboafks and

d~ i(i)i ~

an pus i es an tan s an pianos ...3) 9tainless steel doesn't rust and is used for pans and for fixtures on boats. ('eLSteel may rust and if may not be exaotly "spaoe age" but it's strong and it's awful oheap, and if stillhas a lot of uses. They make oars out of if for one thing... but gone are the haloyon days when oar~bodies were hand-orafted from ash frames and lovingly honed to perfeotion. Now they just shovel ~them out of big presses by the million. Sigh. Mind you there's still the Morgan...

I Aluminium is lisIhL-strong and corrosion-resistant IStrictly speaking you shouldn't say it's "liShf", you should say it has "low densitrj'.Whatever. All I know is, it's a lot easier to lift and rnove around than iron or steel.U9EFUL PROPERTIE9:1) Lishtweishf. (OK, "low density". Happy now?)2) Can be bent and shaped (for rnaking car body panels, etc.)3) 9trong and very rigid when required.4) DOE9N'T CORRODE due to the protective layer of oxide which always quickly covers it.5) It's also a sood conductor of heat and electricity.

DRAWBACK9: Not as strong as steel and a bit rnore expensive.

COMMON U9E9:1) Ladders.2) Aeroplanes.3) Range Rover body panels (but not the rusty tailgate!).4) Drink cans - better than tin-plated steel ones which can rust if darnaged.5) Greenhouses and window frames. ~6) Big power cables used on pylons. ~-

I !Jmper: good conductot easily bent and doesn't corrodeThis is a winning cornbination which rnakes it ideal for:

1) and gas pipes, because it can be bent to shape by hand without fracturing.2) •. because it can be easily bent round corners and it conducts really well.3) Forms useful 'ne alloys such as brass (for trurnpets) and bronze (for statues).

DRAWBACK9: Copper is quite expensive and is not strong.

The Exdting Properties of Metals - learn and enU1J6.Well now, what have e here! 90me chemistry which 19 useful in your everyday life! I reckon it's reaUpretty helpful if you know the difference between various different metals, although I guess it's only rimportant if you plan to build your own steam engine or rocket or something.If you don't, then you'll just have to learn if for fhe Exam and be done with it.

SECTION Two - EARTH MATERIALS

Metals

I The Metallic Crystal Structure I1) All metals have the same basio properties.2) These are due to the speoial type of bonding that exists in metals.3) Metals consist of a giant struoture of atoms held together with

metallio bonds.4) These special bonds allow the outer eleotronls) of each atom to

move freelu.5) This creates a "sea" of free eleotrons throughout the metal which

is what gives rise to many of the properties of metals.

11) Thev all conduct electricity IThis is entirely due to the free eleotrons which oarry the ourrent. ~" ~

12) They're all good conductors of heat I 1'"1'"?:i:Again this is entirely due to the free eleotrons which oarru '1 I "

the heat enerEtJthrounh the metal. Don't try this----_6_0iJ 6 at horne. )

I j) Metals are strong, but also bendv and malleable I ~ YOU;. ~ ~They are strong (hard to break). but they can be bent or ~ ~( ~_

hammered into a different shape. .- \>~( v\:.lt~14) They're all shiny (when freshly cut or IJOIiShedlll~ 11 ,5) Th have hi h meltin and boilin oints f~~

ich means you have to get t em preHy ot to melt them - [t0oo ~ -(except good old mercury). E.g. copper HOO°C.tungsten 33noc.

-6-Th-€1-c-an-b-e-m-ix-e-d-t-o-g-e-th-e-r-t-o-fj-o-rm-m-a-n-y-u-s-e-fu-I-a-/-Io-y:-'S:I 0 _

) __ . ~ of iron and about 1% oarbon. Steel is much less brittle than iron.2. z ~ (mixture) of oopper and tin. It's harder than copper but still easily3J voppe (75%:25%) are used to make oupro-niokelwhich is hard enoug

e've all had enough of this p g

Non-Metals

Non-Metal elements are either dull, brittle solids or they're gases IOnly about a quarter of the elernents are non-metals.Half the non-rnetals are gases and half are solids. Bromine is the only liquid non-metal element.Mercury is the only other elernent which is

liquid (at room temperature, that is).

- except for graphite whichconducts because it has sornefree electrons between the laversof its crystal structure.

j) Non-metals usually bond in small molecules, e.g. 0z-N2

@@

1) Non-metals arepoor conductors of heat

2) Non-metals don't conductelectrici at all

~~~

4) But silicon and carbon form giant structures:Graphite ~(pure carbon) ~

~

Ornamentalglass sword

Donit try this either.Never mind why - just don't.

etc. I

Non-metal Fatigue - I've iust invented it, ZZZZZZZZuuMetals and non-rnetals are really the only things that rnake Chernistry difficult. If it wasn't tothern, the whole subject would be rnuch rnore straightforward. Learn and en;olJ.