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Chemistry - Paper 1 (Bonding and Structure (Giant Covalent Structure -…

- - - - Could help to make new catalysts
      - Fullerenes could be used in nanomedicine to deliver medicine then dissolve in the body easily
      - Some conduct electricity - small electronic chips
      - Silver Nanoparticles have antibacterial properties
      - Cosmetics, moisturisers without making it oily
- - - - Hydrochloric acid - HCL
        Sodium Chloride - NaCl
        Calcium Chloride - CaCl2
        Sodium Carbonate - Na2CO3
        Sulfuric Acid - H2SO4
  - - - Pour the solution into evaporating dish
        Slowly heat the solution. The solvent will evaporate and the solution will get more concentrated. Eventually, crystals will start to form
        Keep heating the evaporating dish until all you have left is dry crystals
    - - Pour the solution into an evaporating dish and gently heat the solution. Some of the solvent will evaporate and the solution will get more concentrated
        Once some of the solvent has evaporated, or when you see crystals start to form remove the dish from the heat and leave solution cool
        The salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution
        Filter the crystals out of the solution, and leave them in a warm palce to dry. You could also use a drying oven or a desicator
- - - - At the negative anode, hydrogen loses electrons to produce H+ ions. This is oxidation
      - At the positive cathode, oxygen gains electrons and reacts with the H+ ions to make water. This is reduction
      - At the negative anode,
        H2 ----> 2H+ + 2e-
      - At the positive cathode,
        O2 + 4H+ + 4e- -----> 2H2O
      - Overall Reaction -
        2H2 + O2 ---> 2H2O
  - - - The exam board will provide a table with different electrodes (electrode A and B) and the voltage
      - If the voltage is negative, than electrode A is more reactive than electrode B.
      - If the voltage is positive, electrode A is less reactive than electrode B.
      - Table
        
        Electrode A Electrode B Voltage
        
        Iron Tin -0.30
        
        iron Lead -0.31
      - The voltage for both is negative so Iron is more reactive than both. The voltage is lower for Lead so Lead is less reactive than Tin. So, if electrode A was Lead and electrode B was Tin, the voltage would be 0.01 V
  - - - Strong Acids and Weak Acids -
        Strong acids ionise completely in water so all particles dissociate to release H+ ions. Weak acids don't fully ionise in water.
        
        pH is a measure of the concentration of Hydrogen ions. For every decrease of 1 on the pH scale, the concentration of H+ ions increases by 10. An acid of pH 4 has 10 times more H+ ions than pH 5 and 100 times more H+ ions than pH 6.
        
        Strong acids and concentrated
        acids are NOT the same thing
- - - - RFM is used a lot with calculating moles of substances
      - It's used in almost every C3 equation so needs to be learned
  - - - This is Avogadro's constant
        which is 6.02 X 10 **23
  - - - Percentage Yield
        
        Quantitative Chemistry that is NOT maths
        
        Conservation
        Of Mass
        
        During a reaction, no atoms are destroyed or created (similar to energy). This means what goes in must come out so the mass before and after have to be the same.
        
        What if the mass
        appears to change?
        
        This will be because it is an open system and there is a gas involved as either a reactant or a product.
        
        Limiting
        Reactants
        
        Reactions stop when one reactant is used up. Usually, (unless the reactants have been perfectly measured) one reactant will be left when the other has been used up. This reactant is in excess.
        
        The reactant which has been fully
        used up is the limiting reactant
        as the reaction can't continue
        because this reactant has run out.
        
        This can be calculated using moles and a balanced equation
        
        Atom Economy
        
        Atom economy is the percentage of useful products to total inputs.
        
        In the exam, it is possible they will ask you to compare different reactions using the atom economy for each and use your opinion on which is better. Make sure to take into account what products are formed (greenhouse gases)
        
        Percentage yield is never 100%.
        There is always a reason why
        some product is lost such as...
        
        Not all reactants form into products (reversible reactions)
        
        There might be side reactions with impurities
        
        You lose some product when you separate it