7.1 - Green Chemistry Flashcards
What are bulk chemicals?
Chemicals that are produced on a large scale in very large quantities.
What are 4 examples of bulk chemicals?
- Ammonia
- Sulfuric acid
- Sodium Hydroxide
- Phosphoric Acid
What are fine chemicals?
Chemicals that are produced on a small scale in much smaller quantities.
What are 3 examples of fine chemicals?
- Drugs
- Food additives
- Fragrances
What are 2 issues with Chemical Research?
- Time-consuming (takes years)
2. Really expensive
What is ensured that chemicals are protected from the people and the environment?
Governments place strict controls and regulations on everything to do with chemical processes.
What are the 3 types of chemical regulations?
- Using chemicals
- Storage
- Transport
What are the 5 stages of chemical production?
- Preparation of feedstock (the actual reactants)
- Synthesis (converting the reactants to products)
- Separation of products (i.e. useful and waste)
- Monitoring the purity of the product
- Handling of by-products and wastes
What are the 8 KEY questions when considering sustainability?
- Will the RAW MATERIALS run out?
- How good is the ATOM ECONOMY?
- What do I do with the WASTE PRODUCTS?
- What are the ENERGY COSTS?
- Will it damage the ENVIRONMENT?
- What are the HEALTH AND SAFETY risks?
- Are there any BENEFITS/RISKS to SOCIETY?
- Is it PROFITABLE?
During a chemical reaction, what happens?
Old bonds are broken. New bonds are formed.
Energy must be _____ to _____ existing bonds. This is called an _________ process.
Energy must be SUPPLIED to BREAK existing bonds. This is called an ENDOTHERMIC process.
Energy is ________ when ___ bonds are _____. This is called an __________ process.
Energy is RELEASED when NEW bonds are FORMED. This is called an EXOTHERMIC process.
If more energy is given out than taken in, what is the overall result of a reaction?
The reaction is EXOTHERMIC.
If more energy is taken in than given out, what is the overall result of a reaction?
The reaction is ENDOTHERMIC.
What are the 5 steps when working out Bond Energy calculations?
- Take a look at the reaction given and separate them into reactants and products.
- Calculate the energy required to break the original bonds (given in the question).
- Calculate the energy released by forming the new bonds (given in the question).
- Use the formula OVERALL ENERGY CHANGE = ENERGY REQUIRED - ENERGY RELEASED to work out the overall energy change.
- If the answer is a negative number, it’s exothermic. If positive, endothermic.
How can Energy Changes be visualised?
Using an Energy Level Diagram.
In exothermic reactions, what is shown on an Energy Level Diagram?
Reactants are higher than products.
In endothermic reactions, what is shown on an Energy Level Diagram?
Reactants are lower than products.
What is the ‘Activation Energy’?
The minimum amount of energy needed to start a reaction.
How is the ‘Activation Energy’ shown on an Energy Level diagram?
It’s the peak of the curve.
What do catalysts do in terms of the Activation Energy?
Catalysts LOWER the activation energy needed for reactions to happen (by providing alternative routes).
If the Activation Energy is high, what does that mean?
Very few molecules may have enough activation energy to start reacting.
If the Activation Energy is low, what does that mean?
Many more molecules may have enough activation energy to start reacting.
What do some industrial processes do to speed up the rate of reaction?
They use enzyme catalysts.
