GCSE: OCR gateway: C3: percentage yield and atom economy + energy
- Created by: 09tvzutphen
- Created on: 09-04-14 21:16
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- C3
- Percentage yield and atom economy
- Calculating Percentage Yield and Industrial Costs
- Used to find out the amount of product should be made from a chemical reaction
- In reallife it is less as practical methords used produces loss
- Percentage Yield: (actual yield/predicted yield)*100
- Industrial proccess have a high percentage yield so
- They reduce the amount of reactants wasted; cost
- Reduce costs by making sure enough reactants used; to little reduces product amount
- Used to find out the amount of product should be made from a chemical reaction
- Atom Economy
- (M of desired products/M of all products)*100
- Industry wants high atom economy
- Reduce production of unwanted products; cost
- Proccess more sustainable by better use of reactants; conserving raw materials
- Calculating Percentage Yield and Industrial Costs
- Energy
- Making and Breaking Bonds
- Bond breaking is endothermic
- Bond making is exothermic
- To decide whether reaction is endo or exo amount of energy made and produced is compared
- Energy needed to break reactants into seperate atoms
- Atoms join to form bonds releasing energy
- More energy released then needed is exo
- More energy needed then released is endo
- Atoms join to form bonds releasing energy
- Energy needed to break reactants into seperate atoms
- Finding Energy Released by Fuels
- Energy transferred (J) = mass of water heated(g) * specific heat capacity of water(J/g^c);4.2 * temperature change
- Energy released by solid fuel
- Find mass of 1g of fuel
- Pour 100g of water into copper calorimeter (1cm3=1g)
- Heat water with burning fuel
- Measure temperature rise
- Repeate with different fuels to ensure fair testing; same distance from flame
- Ensure reliability by repeating resutls
- Fuel burnt = fuel mass before - fuel mass after
- Ensure reliability by repeating resutls
- Repeate with different fuels to ensure fair testing; same distance from flame
- Measure temperature rise
- Heat water with burning fuel
- Pour 100g of water into copper calorimeter (1cm3=1g)
- Find mass of 1g of fuel
- Energy in fuel: Energy per gram = energy released(J)/mass of fuel burnt (g)
- Making and Breaking Bonds
- Percentage yield and atom economy
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