Chemistry 7.1 (Green chemistry)
- Created by: Becca.
- Created on: 21-06-16 09:59
Bulk and Fine
Bulk chemicals are chemicals produced on a large scale eg. ammonia, sulphuric acid...
Fine chemicals are chemicals produced on a small scale eg. drugs, food additives, fragrances...
Factor Bulk Fine
Equipment cost High Low
Production cost High Low
Workforce needed Few Many
Skills needed to work Low High
Government in the Chemical Industry
Jobs in the chemical industry: chemical engineers, health and safety officer, pharmasists...
Gov. controls processes, storage and transport to help protect people and the environment
Storage: locked away, ventilated, box made from a suitable material (won't react with), two reactive chemicals cannot be stored together
Transport: cannot transport above a certain amount/beyond a certain time, needs to be a code on the vehicle, driver must be trained
Processes (syntheis): preparation of feedstock (eg. maize), synthesis (efficient processes, low atom economy, use of catalysts, recycling unused reactants), handling of waste products (reduce hazardous chemicals, find uses for products, reduce overall waste)
Regulations aim to: minimise pollution, encourage uses of renewable resources, eliminate exposure to hazardous chemicals, increase efficiency and cut costs
Sustainablilty
How sustainable a process is depends upon:
1. Feedstock ie. renewable or not?
2. Atom economy, higher is better: (mass of atoms in useful product / mass of atoms in reactants) *100 = %
3. By-products/Waste ie. how much? Recyclable? Useful? Hazardous?
4. Energy inputs/outouts (high energy needed = bad)
5. Environmental impact eg. high pollution
6. Health and safety risks ie. risk of accidents should be minimised
7. Social and economic benefits(compared to previous process): eg. less pollution, lower energy costs
Catalysts
Used to speed up reactions, without being used up in the process eg. enzymes
Catalysts reduce the activation energy needed to begin the reaction
Uses: iron catalyst (haber process), antimony catalyst (polymer manufacture), concentrated sulfuric acid (ester production)
Advantages: more efficient synthesis which increases the yeild (saves money and the environment), lowers temperatures/pressures needed (saves money and energy), enzymes are less toxic than other catalysts (better for the environment)
Catalyst innovation: synthesised based on structure of enzymes because enzymes carry out reaction at room temperature and pressure; more efficient catalysts are created to speed up reactions so smaller reactors are needed to make the same amount of product (lower start up costs)
Enzyme catalysts operate only at specific pH and temperatures (about 37)
Relative Formula Mass
Relative formula mass of a compound is the sum of all of the elements' relative atomic masses
Steps
Example – Find the mass of Zn that can be extracted from 100g of ZnO
❶ Write down the formula
❷ Work out the relative formula mass
❸ Work out the percentage mass of metal in the formula
❹ Work out the mass of metal
❶ The formula is ZnO
❷ RFM is 65+16 = 81
❸ = 80%
❹ In 100g there will be = 80g of Zn
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