MODULAR SCIENCE - ChemistryMODULAR SCIENCE - Chemistry

This gives a taste of chemistry topics that This gives a taste of chemistry topics that will be tested on the final two written will be tested on the final two written paperspapers

Try and learn these facts – you will need to Try and learn these facts – you will need to recall them and maybe apply them to recall them and maybe apply them to something similar!something similar!

Remember: chemistry is all about patterns!!Remember: chemistry is all about patterns!!

Paper 1 - chemistryPaper 1 - chemistry

What you should recall and apply What you should recall and apply from year 10 – all for F/H tier so if from year 10 – all for F/H tier so if on higher paper they will be grade on higher paper they will be grade

C type questionsC type questions

Metals as elementsMetals as elements

Elements are made up of only one type of atomsElements are made up of only one type of atomsThey are arranged in order of their atomic mass They are arranged in order of their atomic mass

and presented on the PTand presented on the PTElements with similar CHEMICAL properties are Elements with similar CHEMICAL properties are

found in columns called GROUPSfound in columns called GROUPSAccording to mass, Ar should be in group 1 and K According to mass, Ar should be in group 1 and K

in group 0 but then they don’t fit the chemical in group 0 but then they don’t fit the chemical pattern – so they were swapped.pattern – so they were swapped.

Now we rank them according to the number of Now we rank them according to the number of protons in their nucleus – and the pattern worksprotons in their nucleus – and the pattern works

MetalsMetals

More than ¾ elements are metalsMore than ¾ elements are metals

Found on the left-hand side of PTFound on the left-hand side of PT

Groups 1,2 and transition metal block between Groups 1,2 and transition metal block between groups 2 and 3groups 2 and 3

Properties of all metals: conduct heat and Properties of all metals: conduct heat and electricity, malleable (bent/hammered)electricity, malleable (bent/hammered)

group 1 vs transition metals group 1 vs transition metals

Li Na K Cu Fe Zn Li Na K Cu Fe Zn

Soft – cut easily Hard, strong, toughSoft – cut easily Hard, strong, tough

Low density – float on HLow density – float on H22O high densityO high density

Group 1 – the alkali metalsGroup 1 – the alkali metals

GROUP 1 metals Li, Na, K all highly GROUP 1 metals Li, Na, K all highly reactive - reactivity increases down groupreactive - reactivity increases down group

Metal + non-metal ionic compounds

Eg. Sodium + oxygen sodium oxide

lithium + chlorine lithium chloride

All ionic compounds are solids, crystalline, white and dissolve in water to form colourless solutions.

Metals and waterMetals and water

Metal + water Metal + water metal hydroxide + hydrogen metal hydroxide + hydrogen

eg lithium + water eg lithium + water lithium hydroxide + hydrogen lithium hydroxide + hydrogen

potassium + water potassium + water potassium hydroxide + potassium hydroxide + hydrogenhydrogen

Hydroxides are alkalis (soluble bases)Hydroxides are alkalis (soluble bases)

Test for hydrogen: light gas Test for hydrogen: light gas squeaky pop squeaky pop

Paper 1: Transition MetalsPaper 1: Transition Metals

Useful as structural materials – iron as Useful as structural materials – iron as scaffolding, copper as electrical wiringscaffolding, copper as electrical wiring

Compounds are Compounds are colouredcoloured CuSO CuSO44==blueblue

nickel chloride=nickel chloride= greengreen CoClCoCl22== pinkpink

Uses – pottery glazes/green weathering roofUses – pottery glazes/green weathering roof

Catalysts: platinum = hydrogenation of oil Catalysts: platinum = hydrogenation of oil to to margarinemargarine

iron: making ammonia ( Haber Process )iron: making ammonia ( Haber Process )

Paper 1: Reactivity SeriesPaper 1: Reactivity Series

A league table of metals according to their reactivityA league table of metals according to their reactivity

A more reactive metal will always displace a less A more reactive metal will always displace a less reactive metal from its oxide or its solutionreactive metal from its oxide or its solution

Eg copper oxide + zincEg copper oxide + zinc zinc oxide + copper zinc oxide + copper

Eg copper sulphate + zinc Eg copper sulphate + zinc zinc sulphate + copper zinc sulphate + copper

Extracting MetalsExtracting Metals

Depends on their position in the reactivity seriesDepends on their position in the reactivity series

K Na Ca Mg Al K Na Ca Mg Al CC Zn Fe Pb Cu Ag Au Zn Fe Pb Cu Ag AuExtract usingExtract using extract usingextract using native native electricity carbon(CO) dig outelectricity carbon(CO) dig out

More energy needed More energy needed less energy needed less energy needed very expensive cheapervery expensive cheaperBut don’t forget rarity = expensive too!But don’t forget rarity = expensive too!

Making SaltsMaking Salts

AcidAcid + + Alkaline Alkaline Neutral + WaterNeutral + Water

Hydroxide SolHydroxide Sol Salt sol Salt sol sulphuric acidsulphuric acid + + sodium hydroxidesodium hydroxide sodium sulphate + water sodium sulphate + water

The type of acid determines the salt name:The type of acid determines the salt name:

sulphuric acid sulphuric acid (metal name)sulphate (metal name)sulphate

hydrochloric acidhydrochloric acid (metal name)chloride (metal name)chloride

nitric acid nitric acid (metal name) nitrate (metal name) nitrate

Year 11 work on structures and Year 11 work on structures and bondingbonding

Changes of stateChanges of state melting evaporation/boilingmelting evaporation/boiling

Solid Liquid GasSolid Liquid Gas freezing condensingfreezing condensing

Atoms are made of 3 particlesAtoms are made of 3 particles

Think Think PENPEN pprotons, rotons, eelectrons and lectrons and nneutrons eutrons

The structure of the atomThe structure of the atomELECTRON –

negative, mass nearly

nothing

PROTON – positive,

same mass as neutron

(“1”)

NEUTRON – neutral,

same mass as proton

(“1”)

The structure of the atomThe structure of the atomParticleParticle Relative MassRelative Mass Relative Relative

ChargeCharge

ProtonProton 11 11

NeutronNeutron 11 00

ElectronElectron 00 -1-1

MASS NUMBER = number of protons + number of neutrons

SYMBOL

PROTON NUMBER = number of protons (obviously)

IsotopesIsotopesAn isotope is an atom with a different number of neutrons:

Each isotope has 8 protons – if it didn’t then it just wouldn’t be oxygen any more.

Notice that the mass number is different. How many neutrons does each isotope have?

A “radioisotope” is simply an isotope that is radioactive – e.g. carbon 14, which is used in carbon dating.

Electronic structureElectronic structureConsider an atom of Potassium:

Potassium has 19 electrons. These are arranged in shells…

Nucleus

The inner shell has _2_ electrons

The next shell has _8_ electrons

The next shell has _8_ electrons

The next shell has the remaining __1 electron

Electron structure

= 2,8,8,1

Ionic bondingIonic bonding

Na

Na

+

This is where a metal bonds with a non-metal (usually). Instead of sharing the electrons one of the atoms “loses” one or more electrons to the other. For example, consider sodium and chlorine:

Sodium has 1 electron on its outer shell and chlorine has 7, so if sodium gives its electron to chlorine they both have a FULL outer shell and are STABLE.

A positively charged sodium ion

A negatively charged chloride ion

As opposed to covalent bonds, ionic bonds form strong forces of attraction between different ions due to their opposite CHARGES, causing GIANT IONIC STRUCTURES to form (e.g sodium chloride) with HIGH melting and boiling points:

Cl

Cl

-

Covalent bondingCovalent bondingConsider an atom of hydrogen:

Notice that hydrogen has just __ electron in its outer shell. A full (inner) shell would have __ electrons, so two hydrogen atoms get together and “_____” their electrons:

Now they both have a ____ outer shell and are more _____. The formula for this molecule is H2.

When two or more atoms bond by sharing electrons we call it COVALENT BONDING. This type of bonding normally occurs between non-metal atoms. It causes the atoms in a molecule to be held together very strongly but there are weak forces between individual molecules. This is why covalently-bonded molecules have low melting and boiling points (i.e. they are usually gases or liquids).

Group 0 – The Noble gasesGroup 0 – The Noble gasesSome facts…

1) All of the noble gases have a full outer shell, so they are very unreactive

2) They all have low melting and boiling points3) They exist as single atoms rather then diatomic molecules4) Helium is lighter then air and is used in

balloons and airships (as well as for talking in a silly voice)

5) Argon is used in light bulbs (because it is so unreactive) and argon , krypton and neon are used in fancy lights

Group 1 – The alkali metalsGroup 1 – The alkali metals

1) These metals all have 1 electron in their outer shell

Some facts…

2)Reactivity increases as you go DOWN the group.

3)They are soft and easy to cut – they float on water

4) They all react with water to form an alkali (hence their name) and HYDROGEN , e.g:

Potassium + water potassium hydroxide + hydrogen

Group 7 – The HalogensGroup 7 – The HalogensSome facts…

1) Reactivity DECREASES as you go down the group

Decre

asin

greactiv

ity

2) They all have coloured vapours: chlorine bromine iodine Because they are non-metals they are brittle and crumbly when solid

3) They exist as diatomic molecules (so that they both have a full outer shell):

Cl Cl

4) Because of this fluorine and chlorine are gases at room temperature and bromine is a liquid.

Chemical formulaeChemical formulae

Methane, CH4

Ethyne, C2H2Sulphuric

acid, H2SO4

Carbon dioxide, CO2Water, H2O

Key

Hydrogen

Oxygen

Carbon

Sulphur

Paper 2 - chemistryPaper 2 - chemistry

What you should recall and apply What you should recall and apply from year 10 – all for F/H tier so if from year 10 – all for F/H tier so if on higher paper they will be grade on higher paper they will be grade

C type questionsC type questions

Hydrocarbons and crude oilHydrocarbons and crude oil

Longer chains

mean…

1. Less ability to

flow

2. Less flammable

3. Less volatile

4. Higher boiling

point

Incre

asin

g le

ng

th

Crude oil is a mixture of HYDROCARBONS (compounds made up of carbon and hydrogen). Some examples:

Ethane

C C

HH

H

HH

H

Butane

C C

HH H

HH

H C C H

H

HH

Fractional distillation - separating Fractional distillation - separating the oil into useful parts (fractions)the oil into useful parts (fractions)

A tall fractionating column is used – cool at A tall fractionating column is used – cool at the top and hot at the bottomthe top and hot at the bottom

The oil is heated up into a gas (vapourised)The oil is heated up into a gas (vapourised)

The smaller molecules go to the top and The smaller molecules go to the top and condense condense bottled gases bottled gases

The heavier ones stay at the bottom and The heavier ones stay at the bottom and condense condense fuel oil and bitumen (road tar) fuel oil and bitumen (road tar)

CrackingCracking

Breaks down (cracks) the big not so useful Breaks down (cracks) the big not so useful hydrocarbon molecules into smaller more useful hydrocarbon molecules into smaller more useful hydrocarbonshydrocarbons

A catalyst and high temperatures are usedA catalyst and high temperatures are used

this is called THERMAL DECOMPOSITIONthis is called THERMAL DECOMPOSITION

New molecules called alkenes are also madeNew molecules called alkenes are also made

Eg Paraffin Eg Paraffin petrol + ethene petrol + ethene

(fuel) (used to make plastic)(fuel) (used to make plastic)

Burning Fuels (hydrocarbons)Burning Fuels (hydrocarbons)

The carbon parts burn to make carbon dioxideThe carbon parts burn to make carbon dioxide

The hydrogen parts burn to make waterThe hydrogen parts burn to make water

Sulphur in the fuel burns to make sulphur dioxide Sulphur in the fuel burns to make sulphur dioxide – this then dissolves to make ACID RAIN– this then dissolves to make ACID RAIN

Hydrocarbons + oxygen Hydrocarbons + oxygen carbon dioxide + water carbon dioxide + water

Plastics like polyethene and polypropene are NOT Plastics like polyethene and polypropene are NOT BIODEGRADABLE – they WILL NOT ROT AWAY BIODEGRADABLE – they WILL NOT ROT AWAY – this causes disposal problems– this causes disposal problems

Earth Structure – the crustEarth Structure – the crust

foldfold

fracture fold

tiltedTurned upside down

At the Earth’s surface sedimentary rocks exist mainly in LAYERS – the top layers are usually the YOUNGEST

HOWEVER the Earth has been subjected to very large forces causing folding, faulting and fracturing of rocks

This demonstrates that the Earth’s crust is very unstablet

You may also be asked to do some data handling on plate movements (tectonics) and the theory behind it

Yr 11 : Patterns of chemical change Yr 11 : Patterns of chemical change – paper 2– paper 2

Topics you should know aboutTopics you should know about

Factors affecting the rate of a reactionFactors affecting the rate of a reactionEnzymes – FermentationEnzymes – FermentationExothermic & Endothermic reactionsExothermic & Endothermic reactionsThe Haber ProcessThe Haber ProcessFertilisersFertilisersRelative Formula MassRelative Formula Mass

i

h

Oxidising Oxidising AgentAgent

ToxicToxic

HarmfHarmfulul

Highly Highly FlammableFlammable

CorrosivCorrosive e

IrritantIrritant

RECOGNISE AND RECALL THESE HAZARD SYMBOLS

Rates of ReactionRates of ReactionChemical reactions occur when different atoms or molecules collide:

For the reaction to happen the particles must have a certain amount of energy – this is called the ACTIVATION ENERGY.

The rate at which the reaction happens depends on four things:

1) The temperature of the reactants,

2) Their concentration

3) Their surface area

4) Whether or not a catalyst is used

Enzymes are biological catalysts. They help the reactions that occur in our bodies by controlling the rate of reaction.

They can be denatured by high temperatures - so they don’t work

Enzymes are denatured

beyond 40OC

EnzymesEnzymes

Yeast is an example of an enzyme. It is used to help a process called fermentation:

Sugar Alcohol + carbon dioxide

The alcohol from this process is used in making drinks and the carbon dioxide can be used to make bread rise.

Enzymes work best in certain conditions:

Enzyme activity

Temp pH pH400C

Could be protease (found in the stomach)

Could be amylase (found in the intestine)

Endothermic and exothermic reactionsEndothermic and exothermic reactions

Step 1: Energy must be SUPPLIED to break bonds:

Step 2: Energy is RELEASED when new bonds are made:

EXOTHERMIC reactions feel HOT because HEAT EXITS

ENDOTHERMIC reactions feel cold because HEAT ENTERS ( energy is lost from your hand!)

Reversible ReactionsReversible ReactionsSome chemical reactions are reversible. In other words, they can go in either direction:

A + B C + D

NH4Cl NH3 + HCl

e.g. Ammonium chloride

Ammonia + hydrogen chloride

If a reaction is EXOTHERMIC in one direction what must it be in the opposite direction?

For example, consider copper sulphate:

Hydrated copper sulphate (blue)

Anhydrous copper sulphate (white)

+ Heat

+ Water

CuSO4 + H2OCuSO4.5H2O

Making AmmoniaMaking Ammonia

Nitrogen + hydrogen Ammonia N2 + 3H2 2NH3

•High pressure

•450O C

•Iron catalystRecycled H2 and N2

Nitrogen

Hydrogen

Mixture of NH3, H2 and N2. This is cooled causing NH3 to liquefy.

Fritz Haber, 1868-1934

Guten Tag. My name is Fritz Haber and I won the Nobel Prize for chemistry. I am going to tell you

how to use a reversible reaction to produce ammonia, a very important chemical. This is called

the Haber Process.

To produce ammonia from nitrogen and hydrogen you have to use three conditions:

Relative formula mass, MRelative formula mass, MrrThe relative formula mass of a compound is blatantly the relative atomic masses of all the elements in the compound added together.

E.g. water H2O:

Therefore Mr for water = 16 + (2x1) = 18

Work out Mr for the following compounds:

1) HCl

2) NaOH

3) MgCl2

4) H2SO4

5) K2CO3

H=1, Cl=35 so Mr = 36

Na=23, O=16, H=1 so Mr = 40

Mg=24, Cl=35 so Mr = 24+(2x35) = 94

H=1, S=32, O=16 so Mr = (2x1)+32+(4x16) = 98

K=39, C=12, O=16 so Mr = (2x39)+12+(3x16) = 138

Relative atomic mass of O = 16

Relative atomic mass of H = 1