2nd Chemistry Exam

1. Components
   1. Proton
   2. Neutron
   3. Electron

1. Oxygen
2. Uranium

1. Water
   1. Purifying
      1. 3 steps

         Nota:

         • Sedimentation Filtration Chlorination
   2. Testing
      1. for sulphate ions

         Nota:

         • Barium Chloride solution
      2. for halide ions

         Nota:

         • Silver Nitrate solution
2. 2 or more elements linked together

1. Group 1 Elements

   Nota:

   • Furthest left on the periodic tableMost reactive metalsReact strongly with OxygenReact violently with water Gain 1 electron to form ions
   1. Examples

      Nota:

      • Potassium Sodium Lithium
   2. Flame tests

      Nota:

      • Lithium-Red Sodium-Orange Potassium-Lilac
2. Group 7 Elements

   Nota:

   • Halogens2nd furthest to the rightUsed in pesticides, plastics and sterilisers Lose 1 electron to form ions
   1. Examples

      Nota:

      • Iodine Chlorine Fluorine
   2. Uses

      Nota:

      • Iodine-Antiseptic Chlorine-Sterilising swimming pool water
3. Transition elements
   1. Form different ions (2+, 3+ etc.)
   2. Form coloured solutions and compounds
   3. Iron (Fe)
      1. Can form a 2+ or 3+ ion
      2. Hydrated Iron(III) oxide=rust

1. Ionic

   Nota:

   • Bonding between a positively and a negatively charged ion
2. Covalent

   Nota:

   • The sharing of electrons
3. Metalic

   Nota:

   • Metal ions stuck together in a sea of delocalised electrons

1. 0 resistance

Nota:

• See book pages 166-171 and 174/5 Too long to talk about on this

1. Moles
   1. Molar masses
2. Percentage composition
3. Concentration

Nota:

• C6H12O6 would become CH2O You divide the bottom numbers by the highest common factor (in this case 2)

1. Dilution
   1. Formula

      Nota:

      • Starting Concentration ---------------------x Starting volume Target concentration
2. GDA (guideline daily amounts)

   Nota:

   • The amount of each substance that someone needs to be healthy
3. Titrations

   Nota:

   • Use indicators such as phenolphthalein.
4. pH curves

   Nota:

   • Shows the pH value of a solution in graphical form
5. Sulphuric acid
   1. Contact Process

      Nota:

      • 3 stages 3 key components (Sulphur, air and water) Conditions must be chosen appropriately

1. Measuring

   Nota:

   • Measure the volumes using a gas syringe and/or by counting bubbles Bubbles are very unreliable as there is no standard measurements for bubble size
2. Volumes

   Nota:

   • Directly proportional to the mass of reactants (double one and the other will double)

Nota:

• At equilibrium the reaction does not stop but the precise same number of reactions happen as counter-reactions The position of the equilibrium can be moved by: the concentration of reactants and products, the temperature changes or the pressure changes

1. Doesn't the picture look like Mrs Barnes and Mr Powell?

1. Weak acids and their uses

   Nota:

   • Example-Citric acid Use- limestone descaling
2. Strong acids and their uses

   Nota:

   • Example-Sulphuric acid Uses- Car batteries, chemistry catalysts
3. Strength of acids determined by the concentration of Hydrogen ions

Nota:

• The decomposition of stable compounds by using an electric current 2 Electrodes -Positive one is an anode which attracts negatively charged anions to it. -Negative one is a cathode which attracts positively charged cations to it

1. Fuel Cells

   Nota:

   • Usually use hydrogen and oxygen Don't need to explain how they work in great detail Applied elctrolysis
   1. Uses

      Nota:

      • Apollo 13 Fuel cells in space Fuel cells on Earth

Nota:

• Oxidation Is Loss of electronsReduction IsGain of electrons

1. Rusting

   Nota:

   • The hydration of Iron (III) Oxide
   1. Sacrificial protection

      Nota:

      • Example-galvanising (iron or steel) The outer coating gives up its electrons first "sacrificing" itself for what we want to protect

1. Fermentation

   Nota:

   • The anaerobic respiration of certain yeasts to create alcohol (see my second biology exam mindmap)
2. Alcohol

   Nota:

   • yum Examples that can be produced by fermentation for human consumption include beer and wineExamples of lethal alcohol include Methanol and PropanolReally all they are is an alkene with some oxygen attached

Nota:

• Ozone is O3 Broken down by CFC's Prevents harmful UV light from reaching the Earth CFCs are now banned due to the Montreal protocol

1. Permanent

   Nota:

   • caused by dissolved calcium sulphate
2. Temporary

   Nota:

   • caused by dissolved calcium hydrogencarbonate Can be thermally decomposed to remove hardness but this causes limescale
3. Removal methods

   Nota:

   • Ion Exchange and some Washing sodas are very good at getting out water hardness

1. Examples

   Nota:

   • Milk Cheese Butter
2. Difference

   Nota:

   • Fats are solid at room temperature Oils are liquid at room temperature
3. Esters

   Nota:

   • Carboxylic acid + alcohol=ester Fatty acids chemically joined to glycerol if it is more complicated
4. Fats in more detail

   Nota:

   • in saturated fats all the carbon-carbon bonds are single covalent bonds In unsaturated fats one or more of the carbon-carbon bonds are double covalent bonds

Nota:

• Hydrophilic head Hydrophobic tail

1. Cleaning
   1. Biological detergents

      Nota:

      • Enzymes digest the stains off of the material being washed
   2. Dry cleaning

      Nota:

      • Use of a solvent called tetrachloroethene Clothes are checked and things that may dissolve are removed Washed in a big washing machine