C6- Chemical Synthesis

Chemical synthesis
1. Process of making complex chemical compounds from simpler ones
2. Useful products are made
  1. Food additives
  2. Cleaning and decorating products
  3. Pharmeceutical drugs
  4. Fertilisers
Chemicals can be produced on a large or small scale
Pharmeceutical industry has largest share of chemical industry
Acids and Alkalis
1. Used in chemical industry
  1. Alkalis
    1. Sodium Hydroxide
    2. Ph of more than 7
    3. Can neutralise acids in chemical industry
2. Acids
  1. Ph of less than 7
  2. Used in chemical industry
Indicators
1. Change colour depending on whether substance is acid or alkaline
2. Litmus paper
  1. If paper turns red; solution is acidic
  2. If paper turns blue; soultion is alkaline
3. Ph meters are more accurate than indicators
Neutralisation reactions
1. Acidic compounds produce aqueous hydrogen ions in water
2. Alkaline compounds produce aqueous hydroxide ions in water
3. Acid + Alkali- Salt + Water
Acids reacting with metals
1. Acid + Metal- Salt + Hydrogen
  1. Hydrogen is confirmed by a 'squeaky pop' test
2. The more reactive the metal, the quicker the reaction
3. Hydrochloric acid will always produce Chloride salts
  1. Hydrochloric acid + Magnesium- Magnesium Chloride + Hydrogen
4. Sulfuric acid will produce Sulfate salts
  1. Magnesium + Sulfuric acid- Magnesium Sulfate
Metal Oxides and Metal Hydroxides
1. Acid + Metal Oxide- Salt + Water
  1. Acid + Metal Hydroxide- Salt + Water
    1. Hydrochloric acid + Sodium Hydroxide- Sodium Chloride + Water
  2. Hydrochloric acid + Copper Oxide- Copper Chloride + Water
Metal Carbonates
1. Acid + Metal Carbonate- Salt + Water + Carbon Dioxide
  1. Hydrochloric acid + sodium carbonate- sodium chloride + water + carbon dioxide
Synthesising Compounds
1. 1.) Choose the reaction
  1. 2.) Risk Assessment
    1. 3.) Calculate quantities of reactants needed
      1. 4.) Choose correct apparatus and conditions
        5.) Isolate product
        6.) Purification
        7.) Measure yield and purity
Calculating Masses in Reactions
Purification and Measuring Yield
1. Filtration
  1. Used to seperate an insoluble solid from a liquid
    1. Solid impurities can be seperated out
2. Evaporation and Crystallisation
3. Evaporation and Crystallisation
  1. Used to seperate a soluble solid from solution
    1. Filters out impurities
4. Drying
  1. Used to dry the project by removing excess liquid
Percentage Yield
1. Actual Yield
  1. Mass of a pure, dry product
2. Theoritical Yield
  1. Maximum possible mass of a product
3. Percentage Yield
  1. Actual yield as a proportion of theoritical yield
    1. Actual Yield divided by theoritical yield X 100
      1. Percentage yield will always be less than 100 percent
Titrations
1. Carried out using a burette
  1. Used to check purity of acidic or alkaline products
    1. They work using neutralisation reactions
      1. You add acid into the burette; which allows you to measure it out drop by drop
        The titration flask at the bottom contains alkali and indicator, if it turns a certain colour you know its an acid
2. Only works with liquids
Energy transfer in Reactions
1. Exothermic reactions
  1. Give out heat
  2. Shown by a rise in temperature
2. Endothermic reactions
  1. Take in heat
  2. Shown by a fall in temperature
3. Energy management is important to control reactions
  1. In exothermic reactions, the heat must be removed before temperature becomes too hot
  2. In endothermic reactions, heat needs to be provided, otherwise reaction will become too cold
Rates of Reaction
1. How fast the reactants are turned into products
2. Its important to control
  1. For safety
  2. For economic reasons
3. The faster the rate, the less money is spent
4. Factors that affect rate
  1. 1.) Temperature
  2. 2.) Concentration
  3. 3.) Catalyst added
Collision Theory
1. Depends on how often and how hard reacting particles collide with each other
  1. Rate of reaction
2. Rate of reaction depends on four things
  1. 1.) Temperature
    1. Particles move faster
      1. They'll collide more frequently
      2. They'll have more energy
  2. 2.) Concentration
    1. More particles makes collisions more likely
      1. Increases rate
  3. 3.) Catalyst
    1. Increases speed of reaction
      1. Encourages colliding particles to stick to where they will collide most frequently
  4. 4.) Surface area
    1. There will be more space; so an increased chance of particle collision
Measuring Rates of Reaction
1. Rate of reaction= Amount of reactant used or product formed divided by time
2. 1.) Precipitation and colour change
3. 2.) Change in mass
4. 3.) Volume of gas given off

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C6- Chemical Synthesis

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