New materials and Chemistry Formulas

Smart Materials

Behave according to conditions (e.g. temperature) Nitol is a shape memory alloy It remembers its old shape when you change it Used for glasses frames Used for braces Pulls teeth into its remembered shape

Nanoparticles

Tiny particles 1-100 nanometers in size Nanoparticles are used in nanoscience New uses are being discovered Has very different properties from the bulk material it is made from Because of huge surface area to volume ratio uses are being discovered Make good catalysts Nanotubes can be used to make stronger, lighter building materials Can be used in socks to prevent smelling Nanomedicine Fullerenes can be absorbed easily Drugs can be delivered to the right cells easily

Fullerenes Can be joined together to form nanotubes Tiny, hallow carbon tubes Covalent bonds make carbon nanotubes very strong

Polymers

Forces between Molecules determine the properties of plastics Strong covalent bonds hold atoms together in long chains

Weak Forces individual tangled chains of polymers Held together by weak intermolecular forces Free to slide over each other

Strong Forces Stronger intermolecular forces between polymer chains Crosslinks hold chains closely together

Thermosetting Polymers Have crosslinks Hold chains together in a solid structure Doesn't soften when heated Strong Hard Rigid

Thermosoftening Polymers No crosslinks Forces between chains are easy to overcome Easy to melt When it cools it hardens into a new shape Can be remoulded

The way you make a polymer affects its properties Starting material and reactions conditions will affect the properties 2 types of polymers are made in these conditions: Low density (LD) Made by heating ethane to 200o Under high pressure Its flexible Used for plastic bags High Density (HD) Made at lower temperature lower pressure With a catalyst More rigid Used for drainpipes

Relative Formula Mass

Relative Atomic Mass Saying how heavy he atoms are compared with the mass of an atom E.g. for carbon it is 12 Relative atomic mass is uasually the same as the mass number (Top number and bigger one)

Relative Formula MassAll the atomic masses in a compound added together

One MoleThe relative formula mass of a substance in grams is known as one mole

E.g. Iron has an Ar of 56So one mole is 56g

Percentage Mass

Used to work out the percentage of a element in a compound

Empirical Formula

Here are the steps List all the elements in the compound Underneath them write their experimental masses or percentages Divide each mass or percentage by the Ar of that particular element Turn the numbers into a simple ratio Get the ratio into its simplest form This is the empirical formula

Percentage Yield

Calculating Masses in Reactions

Here are the steps Write out the balanced equation Work out the Mr-just for the bits you need Then divide you get the amount for 1g then times to get all

Compares actual and predicted amountIt will never be 100% Because: The reaction is reversible Some of the reactants are lost when transferring Sometimes there are other unexpected reactions hapening

Chromatography Lots of dyes may be used to make one dye You can separate the different dyes using chromatography You put the dye on a pencil line on some paper in shallow water The dyes are solvent and so wil rise up the paper

Machines can Analyse SubstancesIt is good because: It's very sensitive (can detect small amounts) Very fast Very accurate

Gas ChromatographyCan separate a mixture An unreactive gas is used to carry the mixture through a column Substances travel through the tube at different speeds They are separated The time it takes to travel is the retention line The recorder draws a gas chromatograph The number of peaks shows the different substances A mass spectrometer can identify the substances leaving the column accurately

Reversible ReactionWhen the products of a reaction can react themselves to produce the original reactants

New Materials

Polymers

Relative Formula Mass

Percentage Mass, Empirical Formula and Masses in Reactions

Percentage Yeild and Chromatography