Chemistry C1 and C01. Equations2. History of Atom3. Structure of the atom4. Electronic arrangement5. Bonding6. Periodic Table History7. Crude Oil8. Alkanes/Alkenes9. Fuels10. Cracking11. Polymerisation12. Polymers13. Atmosphere 14. Pollution15. Esters and smells16. Cooking17. Emulsions and Emulsifiers18. Paints19. Colloids

Equations• Formula of substances needs to be correct• Formulae to learnAlkanes CnH2n+2

Alkenes CnH2n

Sulphuric acid H2SO4

Hydrochloric acid HClSodium Hydroxide NaOHSodium Carbonate Na2CO3

Calcium Carbonate CaCO3

Carbon dioxide CO2

Water H2O

• Equations need to be balanced so same number of atoms on both sides

• Equations you MUST learnCombustion: Alkane/Alkene + Oxygen Carbon Dioxide and Water

Acid/alkali: Acid + Alkali Salt and Water

Acid/Carbonate: Acid + Carbonate Salt, Carbon Dioxide and water

Acid/Metal: Acid + Metal Salt and hydrogen

Examples

• Combustion of methaneCH4 + O2 CO2 and H2O• Combustion of ButaneC4H10 + O2 CO2 and H2O• Hydrochloric acid and Sodium CarbonateHCl + Na2CO3 NaCl + CO2 + H2O

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How did they view the atom?• 400 BC Democritus atom?

• 400 BC Aristotle's opinions The atomic theory was roundly rejected by Aristotle, and, thus, by almost everybody else for the next two millennia.

Greeks

Dalton

• Atoms cannot be created or divided• Everything is made of atoms

JJ Thompson 1896

• The Plum Pudding model

Rutherford 1906

• Alpha particle experiment

Rutherford’s Nuclear AtomRutherford found that most of the particles went through the thin foil undeflected, and some were scattered by a few degrees

Rutherford found that most of the particles went through the thin foil undeflected, and some were scattered by a few degrees ….but some were scattered right back at the source ….but some were scattered right back at the source

In Rutherford’s own words this was equivalent to firing a 15 inch cannon ball at a piece of tissue paper to find that it bounced back and hit you!

In Rutherford’s own words this was equivalent to firing a 15 inch cannon ball at a piece of tissue paper to find that it bounced back and hit you!

Some particles must therefore be colliding with objects much more massive than themselvesSome particles must therefore be colliding with objects much more massive than themselves

The only possible explanation was that the mass of the atom was not distributed uniformly over its volume, but that the majority of the mass was concentrated in a tiny fraction of the volume

The only possible explanation was that the mass of the atom was not distributed uniformly over its volume, but that the majority of the mass was concentrated in a tiny fraction of the volume

Chadwick 1932

• Mass of atom did not equal mass of nucleus (protons) Neutral particle in atom: Neutron

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Model of the atomParticle Charge MassProton +1 1Electron -1 1/1840Neutron 0 1

Atomic Number: Number of protonsMass Number: Number of protons and Number of neutronsNumber of neutrons = Mass Number – Atomic NumberNumber of Electrons = Number of ProtonsPeriod: Number of ShellsGroup: Number of electrons in outer shell

Elements = 7Li 7 = mass number and 3 is atomic number:

Uranium Atomic Number = 92, Mass Number = 238Number of protons = Atomic number = 92Number of electrons = Atomic number = 92Number of neutrons = Mass Number – Atomic Number = 238 – 92 = 146Potassium Atomic Number = 19, Mass Number = 39Number of protons = Atomic number = 19Number of electrons = Atomic number = 19Number of neutrons = Mass Number – Atomic Number = 39 –19 =20

3

3

Electrons in Shell

• The electrons• Found in shells outside of the nucleus• No of electrons in 1st shell = 2 maximum• No of electrons in all other shells = 8 maximum• Shells are filled in order (1st, 2nd etc)• Electrons are only placed in a NEW shell when all

previous shells are FULL

Element Number of electrons

Number in 1st

shellNumber in 2nd shell

Number in 3rd shell

Number in 4th shell

Arrangement Groupof electrons Period

Lithium 3 2 (filled) 1 2,1 Group 1 Period 2

Potassium 19 2 (filled) 8 (filled) 8 (filled) 1 2,8,8,1 Group 1 Period 4

Oxygen 8 2 (filled) 6 2,6 Group 6

Period 2

Silicon 14 2 (filled) 8 (filled) 4 2,8,4 Group 4 Period 3

What is the electron arrangement for the following elements and hence what group and period are they in (CHECK WITH YOUR PERIODIC TABLE)

Calcium Atomic Number 20, Aluminium Atomic Number 13

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Dobereiner 1810• Saw that if elements were ordered • by mass, triads appeared of similarChemistry. Mass of middle = average of others

Unfortunately only these exist SO REJECTED

History of Periodic Table

Newlands 1850

• Ordered elements by mass in eights like octaves (He was a pianist)

Saw some patterns in properties

REJECTED as he placed Iron (solid and metal) under Nitrogen (gas and non-metal)

Mendeleev 1869

Ordered elements by mass in Eights BUT left gaps for undiscovered elementsSwitched elements round (Te and I) so that chemistry was correct even if mass wasn’tACCEPTED as Chemistry was correctReturn to menu

Bonding

• Two Typeshttps://videolibrary.bucksgfl.org.uk/secure/Default.aspx

Ionic – Electrons transferred from NON-METAL to METAL

Covalent - Electrons shared between the NON-METALSDouble Bond = Two covalent bonds between the 2 atomsSingle Bond = One covalent bond between the 2 atoms

Crude Oil• Crude Oil from Dead Fish (Need Heat, pressure and absence O2)• Mixture of hydrocarbons• Separated into fractions via Boiling Point using Fractional distillation• Smaller alkanes have WEAKER intermolecular forces, so have

LOWER boiling points so rise to the TOP of the fractional distillation column (LPG)

• Medium alkanes have stronger intermolecular forces, so have Higher boiling points so rise to the MIDDLE of the fractional distillation column (Petrol)

• Large alkanes have STRONGEST intermolecular forces, so have HIGHEST boiling points so stay at the BOTTOM of the fractional distillation column (Bitumen)

http://videolibrary.bucksgfl.org.uk/Watch.aspx?v=UqzuLg3FVgZI52

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Hydrocarbons

• Carbon and Hydrogen ONLY• Burn to produce CO2 and H2O in a GOOD

supply O2 Complete combustion

• Burn to produce C, CO and H2O in a poor supply O2 InComplete combustion

• Alkanes SATURATED No C=C only C-C

• ALKENES UNSATURATED ONE C=C present (Decolourise Bromine)

Naming Hydrocarbons

• No of Carbons: Prefix (meth, eth, prop, but etc)

• Alkanes: End = ane

• Alkenes: End = ene

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Choosing Fuels• When choosing a fuel we need to consider the

followinga. Ease of Storageb. How much energy the fuel producesc. How easy it is to obtain the fuel and how

much is left d. Is the fuel renewable or non renewablee. When burnt what gases are produced and

how much pollution these causef. The ease of ignition

Burning Hydrocarbons

• Vapour Burns• Ease of combustion is due to volatility (ease

of evaporation)• Bigger alkanes have low volatility so do not

burn well• Bigger alkanes are not used as fuels• http://videolibrary.bucksgfl.org.uk/Watch.aspx?v=dsOH3RglvxPc1O

Test for gases from Complete CombustionONLY CO2 and H2O formed

•WATER: Add Cobalt Chloride paper after condensing any liquid.Paper turns from BLUE to PINK•CARBON DIOXIDE: Bubble gases given off through Lime waterLIMEWATER GOES CLOUDY as a white solid forms

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Cracking

• Converts BIG ( not useful) alkanes into smaller alkanes and alkenes

• REQUIRES HEAT AND ALUMINIUM OXIDE CATALYST• http://videolibrary.bucksgfl.org.uk/Watch.aspx?v=3eymlHBehPgi0l• http://videolibrary.bucksgfl.org.uk/Watch.aspx?v=Gv17NPOJpTLgqz

• In equation of cracking general rule is

Big Alkane Smaller alkene(s) and ONE smaller alkane

• Number of C and H on both sides MUST BALANCEC14H30C12H26 + C2H4 OR C14H30C10H22 + C4H8 OR C14H30C10H22 + 2C2H4

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Polymerisation

• Small Alkenes VERY Large Alkaneshttp://videolibrary.bucksgfl.org.uk/Watch.aspx?v=or1HFUsiVIoiKn

Polymers

• Versatile• Cross Links

Cross Links Rigid and tough

No Cross Links Flexible and soft

Goretex

Membrane: Allows gas molecules through but does not allow liquid molecules through

Waterproof but breathable

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The Atmosphere3.5 billion years ago the atmosphere probably consisted of carbon dioxide (CO2), carbon monoxide (CO), water (H2O), nitrogen (N2), Sulphur Dioxide (SO2) and hydrogen (H2) caused by gases liberated from volcanoes

The water vapour condensed as the temperature cooled to form Oceans

SO2 and CO2 dissolved in the Oceans

Green algae and plants began to photosynthesis 6CO2 + 6H2O C6H12O6 + 6O2

CO2 decreased and O2 increased. CO oxidised to CO2

Some CO2 forms Carbonates which form Limestone and Animal shells

Nowadays the composition of DRY air is78% N2, 21% O2 and 1% Ar. There is about 0.035%CO2

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Deforestation and Burning Fossil fuels

• Trees are being cut down: LESS Photosynthesis: Less CO2 removed

• Fossil fuels are burnt: RELEASES CO2: More CO2 in atmosphere

• CO2 INCREASING. • This causes Global warming. Ocean temps increase• Less CO2 dissolves in the Oceans : Less CO2 removed

• CO2 INCREASING• ETC ETC!!!!!!

Incomplete combustion

• Carbon Monoxide is produced• Odourless/Colourless and very toxic (combines with haemoglobin in blood)

• Nitrogen Monoxide is formed in engines (as N2 reacts with O2 in HOT engine)

• NO causes Photochemical smog AND acid rain• Acid rain dissolves buildings and lowers the pH of lakes killing fish and plants

Catalytic converters convert NO and CO to N2 and CO2

2NO + 2CO 2CO2 + N2

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Esters

• Used as Flavours and Fragrances• How made: Alcohol + (Carboxylic) Acid Ester and Water• You need to add an acid catalyst ,H2SO4. (This is neutralised with Sodium carbonate before use)

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• Need to be: Non-Toxic, Low Volatility, Insoluble in water, Unreactive, Non Irritant

• Then Remember why we might not test on animals- React differently, Cause harm to animals, different from humans

• But then again- We don’t want to test on humans and it shows if the drugs work/don’t work

Esters• Naming of ester made• Look at Alcohol used: Remove the anol and add yl• Look at the Acid used: Remove the ic acid and add ate• Put these two together to get nameMethanol and Methanoic acid GIVE METHyl MethanoateMethanol and Propanoic acid GIVE METHyl PropanoatePropanol and Methanoic acid GIVE Propyl MethanoateButanol and Ethanoic acid GIVE Butyl Ethanoate

• Alcohol and carboxylic acid needed to make ester• Look at name of ester: Remove the yl from the first part. Add anol to

give alcohol• Remove the ate from second part and add ic acid to give acidOctyl Propanoate from Octanol and Propanoic acidPentyl Butanoic acid from Pentanol and Butanoic acidDecyl Nonanoate from Decanol and Nonanoic acid Return to menu

Cooking

• Irreversible change• New products form• Cell walls soften to make vegetables digestible• Proteins denature (change shape) to make meat

digestible

Food AdditivesE number range type of food additive

E 100 to E 199 food colourings

E 200 to E 299 preservatives

E 300 to E 399 antioxidants

E 400 to E 600 flavour enhancers and emulsifiers

Changes colour of food

Stops food going off

Stops food reacting with O2

Helps non-polar and polar liquids to mix

What it does?

Emulsifiers

Polar Molecules and Non-polar liquids do not mix (Immiscible)Polar solvents (water) (Bended by a charged rod) dissolve polar solvents (alcohols)Non-Polar solvents (oil) (Not Bended by a charged rod) do not dissolve in polar solventsNon-Polar solvents will dissolve non-polar solvents

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A lot of food has water (polar) and oil (non-polar) substances in themTo prevent them mixing- an emulsifier is added to the food

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Emulsifier and Emulsions

The emulsifier has a hydrophilic head that ‘looks’ like water (is polar) and a hydrophobic tail that ‘looks’ like oil (is nonpolar) so dissolves in both. This prevents the oil and water separating. The droplets of oil in water mixture is called an emulsion. The emulsifier stabilises the emulsion

SHAKE Droplets of oil form in water when the oil/water mixture is shaken. This forms an unstable emulsion.

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Paints

• Pigment: Coloured particles

• Medium: Solvent

• Binder: Acts like an emulsifier to stop emulsion collapsing

• Smart Paint: Vary properties depending on conditions

Paint Drying

• Water based emulsions (Medium = water, Pigment = Oil)Medium evaporates as the paint dries

• Oil based paints (Medium = Oil, Pigment = Oil)Medium oxidises as the paint dries to form new product. This binds to the surface of the canvas.

Thermochromic Paint

• Changes colour (goes colourless) with increased temperature

Uses:Baby feed bottles: When food is too hot the paint on the bottle changes colour

Bath Mats: When bath is too hot the paint on the mat changes colour

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Phosphorescent Paint

• Glow in dark paint• Absorbs light from the sun and reemits the light in a

darkened room• UsesSafety signsLuminescent watches

Safer than uses a radioactive source to make items glow.http://videolibrary.bucksgfl.org.uk/Watch.aspx?v=hhmuoazokXmr8l

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Colloids

When two solutions are addeda. A precipitate (SOLID) can form. Light cannot

pass through a precipitateb. A colloid (fine solid particles suspended in

solution) can form. Light is scattered by colloids

c. A lot of paints are colloids in which the PIGMENT is present as the colloidal particles

http://videolibrary.bucksgfl.org.uk/Watch.aspx?v=yTIlCi8QJFQ3Hu

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