MC test: Environmental impact of some medications

Multiple choice test on D.6 Environmental impact of some medications

Use the following 'quiz' to test your knowledge and understanding of this sub-topic. As this relates to a sub-topic on the options you may need access to the IB data booklet.

If you get an answer wrong, read through the explanation carefully to learn from your mistakes.

Lead-212 is used to target tumours. It has a half-life of 10.64 hours. What fraction of a sample of Pb-212 will have decomposed after 42.56 hours?

42.56 (4 x 10.64) hours is four half-lives so the amount remaining will be 1/16, so 15/16 will have decomposed.

 

Which are classified as low-level radioactive waste?

I. spent fuel rods from nuclear reactors

II. syringes used to injected solutions of radioactive isotopes into patients for diagnostic purposes

III. rubber gloves used to handle radioactive material

Spent fuel rods contain highly ionizing radioisotopes that tend to have long half-lives so are classified as high-level radioactive waste.

 

Which will always be true when an isotope of an element emits alpha or beta radiation ?

A different element will always be formed as the atomic number changes. If it emits alpha radiation then the mass number decreases but if it emits beta radiation the mass number stays the same.

 

Which may be caused by ionization from radioactive waste?

I. genetic mutations

II. foetal damage

III. leukaemia (malignancy of blood cells)

All three of these (together with an increase in thyroid cancer due to the release of radioactive iodine) have been shown to increase after exposure to ionizing radiation.

 

Which can be formed if chlorinated solvents are combusted and the incineration does not take place at very high temperatures?

Dioxins are extremely poisonous and can be formed when chlorinated hydrocarbons are combusted at low temperatures.

 

Which is the correct expression for atom economy?

The atom economy is not the percentage yield, which is based on the actual mass of the desired product(s) obtained. It is based on the mass of all the atoms in the desired product(s) divided by the total mass of all atoms present in all the products( which is is also equal to the mass of all the atoms present in the reactants) according to the stoichiometric equation, expressed as a percentage.

 

Which is the most environmentally friendly solvent to use in extraction processes?

Supercritical carbon dioxide operates at a lower temperature than other solvents (therefore uses less energy and products and reactants are less likely to be decomposed thermally), and is less harmful to the environment. It does not contribute to the greenhouse effect as it is sourced from the atmosphere so there is no net increase in carbon dioxide in the atmosphere.

 

The diesterification of morphine to produce diamorphine can be brought about using ethanoic acid, CH3COOH, ethanoyl chloride, CH3COCl or ethanoic anhydride, (CH3CO)2O as the acetylating agent. Other than diamorphine, the respective products are water, hydrochloric acid and ethanoic acid. Which acetylating agent produces the reaction with the highest atom economy?

Since water has the lowest molar mass of the three possible products (other than diamorphine) the percentage of diamorphine in the products using molar masses will be greatest when water is the product.

 

Which are important to take into account when considering the 'greenness' of a solvent?

I. the energy and materials used to mIB Docs (2) Teamfacture the solvent

II. the amount of waste solvent that cannot be recycled

III. the toxicity of the solvent

All three factors are important. As well as the toxicity of the waste solvent on the environment, the hazards caused by inhaling the vapour by the workforce during its use should also be considered.

 

One example of the use of green chemistry is the use of shikimic acid as a precursor to a particular drug? Which drug uses shikimic acid as its precursor?

Shikimic acid can be obtained from the Chinese star anise plant but is now obtained commercially in a more environmentally friendly way using bioengineering. It is used to make Tamiflu (oseltamivir).

 

 

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