Chemistry Y3 MYE

Chemistry Y3 MYE

1. Kinetic Particle Theory

   • States of Matter
     • Solid
       • Strongest Force of Attraction, Least KE of Particles, Closely-Packed Arrangement, vibrate about fixed position
     • Liquid
       • Weaker Force of Attraction, More KE of Particles(Slide/Roll/Move across one another), Particles still touching one another, Free moving particles, takes shape of container
     • Gas
       • Weakest Force of Attraction, Most KE of Particles, particles far apart, Move freely/rapidly/randomly.
   • Diffusion
     • From area of high conc. to area of low conc.
       • **however there is still diffusion between two areas at equilibrium, just 0 net
       • Factors
         • Molecular Mass
           • Gas that is higher molecular mass will diffuse slower
         • Temperature
           • Higher Temp, Higher KE, Higher Diffusion
   • Changes in State
     • Melting, Freezing, Boiling, Condensation, Sublimation (solid to gas), Deposition (gas to solid)
       • No temperature change during changing of state as energy is used to break/form bonds. Increasing internal potential energy not internal kinetic energy

2. Separation Techniques

   • Mixture
     • Solid FROM Liquid
       • Insoluble Solid
         • Filtration
           • Filter Funnel n Filter paper
       • Soluble Solid
         • Heating
           • Heat solution to boil water away, leaving solid behind
             • Solid is impure (other sediments), and wet
               • dry between 2 filter paper
                 • Not all solutions can (e.g sugar will caramelise)
         • Crystallisation
           • Solution heated to remove most of solvent (saturated solution left)
             • Leave solution to cool n crystallise
               • Filtrate to remove remaining solvent
                 • scoop that crystals out n wash with cold deionised water
                   • dry between 2 filter paper
                   • Cold n deionised to prevent dissolving (wash to get rid of impurities)
     • Solid FROM Solid
       • Using Solvent in which only 1 solid is soluble
         • e.g water/ethanol
       • Sublimation
         • When only one only able to sublime (iodine, ammonium chloride)
           • use inverted funnel w/ wet cloth above heated solution
       • Magnet
         • When 1 magnetic n 1 non-magnetic material
     • Liquid FROM Solution
       • Simple Distillation
         • when liquids b.p are at least 50degcel apart
           • Thermometer next to opening of condenser to monitor temp.
           • Boiling chips for smooth boiling
           • Can use ice to keep volatile liquids in liquid state
           • Water enter from bottom of condenser to ensure condenser always full
       • Separating Funnel
         • Separate Liquids of different densities
       • Fractional Distillation
         • Separate liquids with similar b.p
           • Same as simple just w/ extra fractionating column
           • fractionating column to prevent evaporating vapors from leaving
             • During boiling, temperature will not change, hence will finish boiling lowest b.p first and so on
       • Chromatogrpahy
         • 2 solutes in same solvent
           • Principle: Different solute got different solubility in solvent. Higher Solubility, faster n higher up the paper it will travel
             • If only one colour (the solute) then substance is pure
               • If dots are colourless, dip in locating agent after
           • Retention Value (Rf)
             • the longer the paper is in solvent, higher the substances will go
               • ratio of component to start and solvent to start will remain the same
                 • Each component got constant Rf Value that does not change in same conditions

3. Elements, Compounds, Mixtures

   • Chemical Naming: Cation then anion
     • name hacks
       • Anions: -ide
       • Metals: -ium
       • Anion of hydrogen is hydride
       • Anion of halogen is halide
       • 5 onwards: penta, hexa, hepta, octa, nona, deca
     • (some) Polyatomic ionic compounds
       • Phosphate (PO4^3-), Carbonate (CO3^2-), Ammonium (NH4+), Sulfate (SO4^2-),
     • if both cation/anion, lower group first.

4. Mole Concept/Chemical Calculations

   • Isoelectronic = Elements hv same total of electrons, Isotope = Same elements but different number of neutrons
     • Isotopic Abundance
       • If a = 40% and b = 60%
         • Ar = (a x 40%) + (b x 60%) / 100
     • Same Valance electrons - Similar chemical properties. Same no. of neutrons, similar physical properties
     • Allotropes: everything same just structure different
   • Ionic Equations
     • same as normal eqns but split up aqueous compounds and cancel out repeating aq ions on both sides of eqn. (spectator ions)
       • If you see ions in eqn, it is aq state
   • Equal Vol. of Gas = equal no. of moles
     • Molar Volume of 1mol of any gas is 24dm^3
       • Formula: Volume (dm3) = Mole (n) x Molar Volume (dm3/mol)
         • Other Useful formulas: Moles = Mass / Molar Mass
           • One More: Mole = Concentration (mol/dm3) x Volume (dm3)
             • I lied: Mass = Concentration (g/dm3) x Volume (dm3)
   • Empirical formula
     • Simplest ratio of elements in compound
       • n = Mr(Molecular Formula) / Mr(Empirical Formula)
   • Titration
     • Slow addition of solution of known concentration (titrant, burette) to known volume of unknown concentration (analyte, conical flask) until neutralisation

5. Limiting Reactants + Percentage Yield

   • In reaction, not all reactants might be used up. Reactant that gets completely used up is limiting reactant, not used up is excess reactant
   • Theoretical Yield is always greater than experimental Yield
     • Formula 1: (Mass of Product) / (Mass of Calculated Product) x 100%
       • Formula 2: (Experimental Yield) / (Theoretical Yield) x 100%
         • Formula 2.5 for Purity: Mass of Pure reactant / Mass of impure reactant x 100%

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