Green chemistry
YOU SHOULD BE ABLE TO:
Define green chemistry. Outline the principles of green chemistry.
Green chemistry is described as the utilization of a set of principles that reduce or eliminate the use or generation of hazardous substances in the design, manufacture and application of chemical products. Green chemistry can also be called sustainable chemistry and seeks to reduce and prevent pollution at its source. The main principles involved in green chemistry are: 1. Prevent waste – Preventing the production of waste is better than cleaning up afterwards. 2. Maximise atom economy – Increases yield and performance. 3. Less hazardous chemical syntheses; use processes which require fewer chemicals.
4. Safer chemicals and products – Make products that are not toxic to human health.
5. Safer solvents and reaction conditions – Make products that are not toxic to the environment.
6. Increase energy efficiency – Reduce the energy requirements for chemical processes.
7. Use renewable feedstocks – Invest in renewable raw materials instead of depleting finite resources. 8. Avoid chemical derivatives. 9. Use catalysts – To reduce reaction times, thus maximising energy efficiency.
10. Design chemicals and products to degrade after use – Waste products should be designed to be biodegradable as this ensures reduced impact on the environment. 11. Analyse in real time to prevent pollution. 12. Minimise potential for accidents – This reduces the risk of explosions and fires by practising workplace and environmental health and safety.
BENEFITS OF GREEN CHEMISTRY
The benefits of practising green chemistry will be enjoyed by all stakeholders: businesses, the environment and the human capital.
Businesses benefit by having improved resource efficiency, lower material costs and utility bills. By opting to use environmentally friendly products and processes, businesses help to catalyse the designing of new and ‘greener’ environmental technology solutions.
Humans and other biotic life would benefit from a cleaner and safer environment. The increased use of environmental technology would also lead to the creation of new job markets. Green chemistry, therefore, has environmental and economic benefits. Installing new environmental technology may incur significant costs in the initial stages. However, the expected savings would be obtained over time as energy costs decrease.
Ultimately, the environment benefits as more materials are recycled or reused, ensuring the conservation of precious resources. A cleaner environment will also result, as less chemicals are released into the environment. Chemical and industrial processes that use cleaner production technologies will reduce emissions and have less of an impact on the environment.
The reality of climate change calls for the use of sustainable production practices of which green chemistry is an example. Through this practice, energy will be saved, depleting resources will be minimised, new and alternative energy sources will be embarked on which will help to minimise global environmental changes.
REVIEW
1. How does green chemistry help the environment? 2. Why is green chemistry called sustainable chemistry? 3. How does lower energy cost help businesses? 4. Outline the basic principles of green chemistry.
EXAMINATION TIPS AND REMINDERS
Please remember to read the questions carefully and answer them as clearly as possible so that the examiner can understand what you are trying to say.
Writing a lot and being vague will not guarantee the marks if what is being asked is not answered.
Be relaxed with calculation questions by practising using formulas and memorising them.
To ensure that you are fully preparing for your exams, try practising past-paper questions under exam conditions. In other words, try answering the questions in the time normally set for the exams. In this way, you will get used to working fast and with a time limit.
Scoring maximum marks from the questions on the exam paper will depend on how well you follow the instructions asked.
If you are asked to explain your answer, or to describe, this means that it requires more information than just listing.
Also, look at the marks assigned to each part of a question. More likely, the length of your answer to a one mark question should be significantly less than that required for a five mark question. ALL THE BEST IN YOUR CHEMISTRY EXAMS!