OCR A-Level Chemistry B H433
Development of Practical Skills in Chemistry
Elements of Life
Developing Fuels
Elements From the Sea
The Ozone Story
What's in a Medicine?
The Chemical Industry
Polymers and Life
Oceans
Developing Metals
Colour by Design
Chemical Literacy
Mathematical Skills in Chemistry
The Chemical Industry
Costs, benefits and risks of industrial processes
- 4 things to know
- Components 01, 02 and 03
Overview
Recall questions on saleable co-products, the double cost of a by-product, energy recovery, plant capacity and location.
What you need to know
Answer each one before you reveal it.
Why is energy recovery designed into a chemical plant, why does running below design capacity raise the cost per tonne, and how does the location of a plant affect its costs?
Why is the transport of a chemical sometimes riskier than its manufacture?
Why can the hazard of a substance never be reduced by a change in working practice, whereas the risk can?
Questions from this subtopic
Each one with the model answer underneath.
- 1
Name four categories of cost that must be considered when running an industrial chemical process.
Model answer
The cost of raw materials, the cost of energy, the capital and maintenance costs of the plant, and the cost of dealing with by-products and waste.
- 2
What is a fixed cost in the context of a chemical plant?
Model answer
A cost that must be paid whether or not the plant is producing, such as the capital repayment on the buildings and reactors.
- 3
Give two examples of variable costs.
Model answer
Raw materials and energy, since both scale with the quantity of product made.
- 4
How does a saleable co-product improve the economics of a process?
Model answer
Income from selling it offsets the production costs and reduces the amount of waste that must be treated.
- 5
Why is an unwanted by-product a double cost?
Model answer
Reactant mass has been used to make something worthless, and money must then be spent treating or disposing of it safely.
- 6
A plant makes 500 tonnes of product a day and needs 0.80 tonne of raw material per tonne of product, at £220 per tonne. Calculate the daily raw material cost.
Model answer
The plant uses 400 tonnes a day, so the cost is 400 × £220 = £88 000.
Other ways to work this
The same content, four other ways.
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