C3: Chemical Economics (OCR Gateway Chemistry)

Rates of Reaction 1

  • Particles need to collide with enough energy to react
    • If there isn't enough energy they just bounce off each other
  • Activation Energy: minimum amount of energy needed in a collision for the particles to react


  • particles have more energy at higher temperatures
  • they collide more frequently with more energy so the rate of reaction increases

Concerntration and Pressure

  • (concerntration of a solution tells you how many particles there are in a solution (mol/dm³))
  • higher concerntration and more pressure means that the particles ar emore crowded--> more frequent successful collisions= faster rate of reaction
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Rates of Reaction 2

Surface Area

  • collisions only occur on the surface (reaction with solid and acid)
  • higher surface area means more particles are exposed (eg. powder vs solid lumps)


  • a catalyst is a substance that speeds up a reaction without being used up
  • they aren't used up during the reaction
  • they give a surface for the particles to stick to
  • particles can collide with less energy because they reduce the activation energy
  • helps them collide with the correct orientation
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Relative atomic mass

Relative atomic mass

  • a measure of one atoms mass.
  • eg. relative atomic mass of sodium = 23 (22.99)


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Relative formula mass

Relative Formula Mass

  • measure of the mass of a compound
  • eg. relative formula mass of H₂O = 18

(2 x Relative atomic mass of Hydrogen ) + (1 x Relative atomic mass of Oxygen)

= (2 x 1) + (1 x 16)

= 2+16


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Percentage yield

Percentage yield: the amount of product you actually made as a percentage of the theoretical amount

  • some of it may be lost during the transfer (flitering etc.)

     actual yield
                               x 100 = percentage yield
 theoretical yield

I made 100g of copper sulfate (CuSO₄), what was the percentage yield of my experiment?

  •  theoretical yeild is the relative formula mass
  • RFM of CuSO₄ = 63 (Copper) + 32 (Sulfur) + 4x16 (Oxygen)
  • =159
  •                                 100
  • percentage yield =          x 100% = 63%
  •                                 159
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Atom Economy

  •                                   mass of desired product
  • Atom economy =                                                  x100%
  •                                  total mass of all products

Eg. What is the atom aconomy of H₂O (Hydrogen is the desired product)

  •        2x1                               2
  •                        x100%  =            x100%  
  •  (2x1)+(1x16)                      18
  • atom economy = 11% 

high atom economy is more sustainable as you are producing more of the product you want. Any atom economy that is below 90% is considered quite low and is not sustainable.

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Batch Process

  • The batch process is used to make chemicals that are needed in small amounts
    • eg. drugs and medicines
  • production doesn't go on all the time
  • only makes it when required


  • you can use the same equiptment over and over again
  • equiptment is cheap


  • has to be constantly supervised and is labour intensive and costly
  • takes time to clean up every time
  • it is inefficient- doesn't produce the chemicals all the time
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Continuous Process

  • you can produce large amounts of chemicals
  • works 24 hours a day, 7 days a week
    • eg. the harbor process used to make ammonia


  • product is made 24/7, cost of product is cheap
  • high production rate


  • high set up is expensive
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Exothermic Reactions

  • chemical reactions where heat is given off to the surroundings
    • eg. combustion of a fuel (burning of a fuel)
  • bond making is exothermic, it releases energy
    • the energy released in bond formation is greater than the energy used to break the old bonds
  • reactants lose energy throughout the reaction
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Endothermic Reactions

  • heat is taken into the reaction
    • eg. photosynthesis or thermal decomposition
  • bond breaking requires energy
    • energy used to break bonds is higher than the energy used to make bonds
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Measuring Energy Given off By Fuels

E = m x c x t

  • energy given off (J) = mass of water (g) x specific heat capacity (always 4.2 in water) x temperature of water (℃)
  •                                   energy given off (J)
  • energy per gram=                                       
  •                                  mass of fuel burnt (g) 
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Manufacture of Pharmaceuticals

Why is it so expensive to manufacture new pharmaceuticals?

  • research and testing (takes years- animal/ human testing)
  • labour costs (requires specialist workers)
  • raw materials (requires rare materials that are hard to get hold of)
  • cost of patent (the legal costs)
  • marketing
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Extracting Chemicals from Plants

1) Chop and crush the plant (with sand to break the plant cell wall)

2) Dissolve the plant in a solvent (example. acetone)

3) Filter the liquid using paper chromatography to separate the chemicals.

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Allotropes of Carbon: Diamonds

Allotrope: different structure of an element

properties of diamonds:                 uses:

colourless                                       jewellery- transparent and shiny, insoluble in water
hard                                                cutting tool- hard and strong due to 4 covalent bonds
high meltingpoint
insoluble in water
doesn't condut electricity

Why does it have a high melting point? 

The four covalent bonds connecting the 4 carbon atoms are very strong and require lots of energy to break.

Why doesn't it conduct electricity?

There are no free or delocalised electrons, they are all used to creat covalent bonds.

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Allotropes of Carbon: Graphite

properties:                                 uses:

  • black and opaque                pencils- slippery, the layers can slide off one another
  • soluble in water                    lubricants- slippery
  • conducts electricity
  • slippery

Each laters are connected with weak intermelecular forces

Why does it conduc electricity?

  • There are only three covalent bonds, so there is one free electron which is delocalised.
  • It can flow inbetween the laters which creates the electric current- flow of electrons.
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Allotropes of Carbon: Buckminster Fullerene

  • they are like hollow balls of carbon
  • like a cage


  • to deliver drugs - they are stored inside the 'cage' and are slowly let out so they aren't given                                 out in a high concerntration at ones, this reduces the side effects
  • for carbon nanotubes - buckminster fullerene is opened and put into a tiny tube of carbon                                               (10⁻⁹m is nanosize)                                                                                                                       - the carbon nanotubes are very strong
    • used in tennis rackets
    • for a catalyst - they have a large surface area
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thanks for this.

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