Chemistry.
1. What is meant by the term ‘bulk chemicals’? Give some examples.
Bulk chemicals are chemicals that are produced on a large scale, some examples of these are sulphuric acid, ammonia and sodium hydroxide.
2. What are fine chemicals? Give an example.
These are chemicals that are produced on a smaller scale to that of bulk chemicals. Some examples are food additives, drugs and fragrances.
3. Describe the five stages used in industry producing chemicals?
The first of the five stages is source the raw materials and turn them into feed stocks. The second is synthesis, where the actual reaction happens to make the product. Thirdly, synthesis, this includes separating the product you actually want from by-products and waste. The fourth stage is to monitor the purity of the product, as some other unwanted products may still be mixed in with it. We have to make sure that the purity levels are between certain levels. Sometimes a slightly impure product will still do the job so there is no point in wasting money in a purification process. Finally, the fifth stage is to deal with the by-products and waste, as they can usually be used in another reaction so are sold on. If the reaction was exothermic the heat be used for other reactions saving energy and money. We have to be extra careful when dealing with waste because there may be environmental concerns and legal requirements that have to be followed.
4. What are the eight questions that you should consider when deciding if a process is sustainable?
Will the raw material run out? If the reactants are renewable that’s great, but if not they may run out.
How good is the atom economy? If its low you can use lots of resources quickly and not get much product.
What do I do with the waste product? Will it cause pollution? Will there be useful by-products?
What are the energy costs? Lots of energy is very expensive. Burning fossil fuels is not good for the environment
Will it damage the environment? If the reaction produces harmful chemicals it will damage the environment. Transportation pollution. Mining ruining countryside.
What are the health and safety risks? Companies have to test products to make sure they are safe to use. There are laws about the public and workers safety when producing chemicals.
Are there any benefits or risks to society? A factory brings money and jobs to the local area, however it may be unsightly and dangerous.
Is it profitable?
5. An exothermic reaction is what that gives out heat/energy to the environment and an endothermic reaction is one that uses energy from its surroundings/environment.
6. Calculate the energy change from this reaction?
Bond
Energy +/- (KJ/mol)
H-H
+436
Br-Br
+192
H-Br
+366

Reaction:
H-H+Br-Br 2H-Br
436+192=628 Bonds broken = 628
366+366=732 Bonds made=732 Overall change = Bonds broken-Bonds formed
Therefore: 628-732=-104KJ/mol
The answer is negative showing me that the reaction is exothermic
7. A catalyst is a substance that changes the speed of a reaction, without it being used uo in the reaction. Catalyst lower the activation energy needed for reactions to happen by finding alternative routes, however the overall energy change remains the same.
8. A revisable reaction can go both ways. It is one where the reactants react to form a product but the products can then react themselves to form the original reactants.
9. If a reversible reaction takes place