Topic 1.7 Introductory organic chemistry

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Topic 1.7Introductory organic chemistry
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About organic chemistry hazard and risk in
organic chemistry

• Objectives - To be able to
• appreciate the difference between hazard and risk
  
• understand the hazards associated with organic
  compounds and why it is necessary to carry out
  risk assessments when dealing with potentially
  hazardous materials
• suggest ways that risk can be reduced and
  reactions can be carried out safely

Starter - Sketch the labels for the following
hazards Corrosive, harmful, toxic, flammable,
dangerous to the environment What colour are
these labels?

• Crowe2008

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What captions appear on these labels?
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(No Transcript)
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What is chemistry?
Chemistry is the science concerned with the
composition, structure, and properties of matter,
as well as the changes it undergoes during
chemical reactions.
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Areas of chemical study
Inorganic chemistry, the study of inorganic matter
Organic chemistry, the study of organic matter
Physical chemistry, the energy related studies
of chemical systems
Analytical chemistry, the analysis of material
samples to gain an understanding of their
chemical composition and structure.
Biochemistry, the study of substances found in
biological organisms
Plus many other sub-divisions
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The core principles of chemistry

• Chemical Ideas
• Understanding and explaining the ways in which
  different chemicals react with one another.

• How Chemists Work
• Seeing how chemical theory and knowledge has been
  developed and extended over time.
• Building your own practical skills.

• Chemistry in Action
• Use and abuse of chemicals.
• Recycling sustainability.
• Ethics Economics

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Organic Chemistry
This is the study of the compounds of carbon,
except for carbon monoxide, carbon dioxide and
the carbonates.
Why are there so many carbon compounds? What is
unusual about the way that carbon can form bonds?

• Carbon is in Group 4 and so can form four
  covalent bonds
• It can also form double and triple bonds
• It forms chains and rings of carbon atoms joined
  together
• Such chains and rings of carbon atoms are the
  basis for whole families of organic molecules,
  such as
• hydrocarbons, carbohydrates, proteins, amino
  acids etc.

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Hazard Risk in organic chemistry
Hazard the potential to do harm Suggest some
hazards in the laboratory
1. Hazards presented by the substances themselves
2. Hazards arising from the activities performed
in the laboratory heating, pouring, spilling,
etc.
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Hazard Risk in organic chemistry
Risk the chance that a particular hazard
will actually cause harm.
Risk is affected by a number of things, in
particular the nature of the hazard and the level
of exposure involved..
Affected by

• Expertise of person
• Quantities being used
• Conditions in which it is used
• Protective clothing equipment used

A hazardous substance can be safe to use if the
risks are minimised
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• How science works managing hazard, calculating
  risk
• See active book p97
• Write the five steps needed to make a risk
  assessment

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Ways of reducing risk

• Working on a smaller scale
• What is the advantage here if
• The substance produces harmful fumes?
• The reaction is exothermic?
• The substance needs to be poured from one
  container into another?

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Ways of reducing risk
2. Taking specific precautions or using
alternative techniques depending on the
properties of the hazardous substances
used. e.g. concentrated acids and alkalis are
corrosive, whereas their diluted solutions are
irritants. Many reactions can be performed using
diluted reagents, however there are certain
reactions where the concentrated chemical must be
used, what precautions could you take to minimise
the risk?
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Ways of reducing risk
3. Careful use of fume cupboards and personal
protection, considerably reduce the risk of
carrying out reactions using hazardous
chemicals (a) What are the benefits of carrying
out a reaction in a fume cupboard? (b) Make a
list of personal protection items that you could
use while performing an experiment.
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Ways of reducing risk
4. Changing the conditions under which a
reaction takes place How would lowering the
temperature of a reacting mixture reduce risk?
Less chance of overheating Less chance of harmful
fumes being released
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Ways of reducing risk

• 5. Using alternative methods with less harmful
  substances
• Sometimes it is possible to substitute a
  hazardous chemical with one that is less
  hazardous. However, In many cases the replacement
  chemicals are less effective (e.g. slower
  reaction, lower yield of product). Suggest why
  these methods are still used?
• The risk is lower and so the disadvantages are
  worthwhile.

See active book pp98/99 HSW pesticides and
comparative risks
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Summary Questions

1. What is the difference between hazard and risk?
2. Why are chemical and explosives laboratories
   relatively safe places to work?
3. What ethical issues would you need to consider
   when deciding whether to use natural or synthetic
   pesticides on a large scale?