AE9: Molecules & Drugs

 

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Source: https://www.tumblr.com/search/easy%20drugs%20easy%20life

1. In allergy sufferer, histamine causes runny noses, red eyes, and other symptoms.

a. Give the chemical formula for this compound.

b. Circle the amine functional groups in histamine.

c. Which part (or parts) of the molecule make the compound water-soluble?

Answer:
a. C5H9N2
b.
c. N atoms have negative dipole moments which can form hydrogen bonds with H+ of H20 molecules

 

2. Antihistamines are widely used drugs for treating symptoms of allergies caused by reactions to histamine compounds. This class of drug competes with histamine, occupying receptor sites on cells normally occupied by histamine.

a. Give the chemical formula for this compound.

b. What similarities do you see between this structure and that of histamine (shown in the previous question 1) that would allow the antihistamine to compete with histamine?

Answer:
a. C16H21N3
b. Two-carbon chain with an N at the end and a three atom sequence N-C-N.

 

3. Consider this statement. ‘Drugs can be broadly classed into two groups: those that produce a physiological response in the body and those that inhibit the growth of substances that cause infections.” Into which class does each of these drugs fall?

Answer:

Physiological response

-aspirin

-morphine

-estrogen

-amphetamine

Inhibit growth of substances

-(Keflex) antibiotic

-Penicillin

 

 

 

4. Herbal or alternative medicines are not regulated in the same way as prescription or OTC medicines. In particular, the issues of concern are identification and quantification of the active ingredient, quality control in manufacture, and side effects when the herbal remedy is used in conjunction with another alternative or prescription medicine.

a. What do you think is the evidence from herbal supplement manufacturers that address these issues?

b. Do you know anything about Singapore’s legislation on the topic?

Answer:
a. Products like herbs are sometimes tainted with germs, pesticides, or toxic heavy metals. Other supplements do not contain what’s listed on the label. This is because some herbal manufacturers mix or substitute products with cheaper alternatives. As such, the purity of these medicines become obscured as testing becomes less reliable.
b. We know that there is currently not much strict enforcement of legislation but regardless dealers have the responsibility to ensure that their health supplements do abide with safety and quality standards.

AE 7: The World of Polymers and Plastics

Source: https://i.ytimg.com/vi/YcLS_FF6wfs/maxresdefault.jpg

1. When Styrofoam packing peanuts are immersed in acetone, they dissolve. If the acetone is allowed to evaporate, a solid remains. The Solid still consists of Styrofoam, but now it is solid and much denser. Explain.

Answer: Styrofoam is composed of 98% air. When polystyrene dissolves in acetone, the air in the foam is released, thus compacting the Styrofoam into a solid which is much denser.

2. Consider Spectra, Allied-Signal Corporation’s HDPE fiber, used as liners for surgical gloves. Although the Spectra liner has a very high resistance to being cut, the polymer allows a surgeon to maintain a delicate sense of touch. The interesting thing is that Spectra is linear HDPE, which is usually associated with being rigid and not very flexible.

a. Suggest a reason why branched LDPE cannot be used in this application.

b. Offer a molecular level reason for why linear HDPE is successful in this application.

Answer:

a. Branched LDPE are softer and more flexible but have lower tensile strength, thus, during a surgery, it may break easily exposing surgeons to viruses or bacteria present.

b. The polymer chains in HDPE, on the other hand, are more linear. They pack closer together, resulting in greater intermolecular forces and a more “crystalline” structure. HDPE has greater tensile strength than LDPE.

3. When you try to stretch a piece of plastic bag, the length of the piece of plastic being pulled increases dramatically and the thickness decreases. Does the same thing happen when you pull on a piece of paper? Why or why not? Explain on a molecular level.

Answer: No it does not happen to paper. For plastic bags, the molecules are packed together with high degree of branching, thus creating a less strong intermolecular forces which results in lower tensile strength and increased ductility. This happens in the opposite manner for paper whereby paper has a low ductility characteristic.

4. A Teflon ear bone, fallopian tube, or heart valve? A Gore-Tex implant for the face or to repair a hernia? Some polymers are biocompatible and now used to replace or repair body parts.

a. List four properties that would be desirable for polymers used within the human body.

b. Other polymers may be used outside your body, but in close contact with it. For example, no surgeon is needed for you to use your contact lenses—you insert, remove, clean, and store them yourself. From which polymers are contact lenses made? What properties are desirable in these materials? Either a call to an optometrist or a search on the Web may provide some answers.

c. What is the difference in the material used in “hard” and “soft” contact lenses? How do the differences in properties affect the ease of wearing of contact lenses?

Answer:

a. The properties are (1) stable over time of intended use, (2) non-toxic, (3) inert and (4) light. Other factors to consider are low cost, lack of solubility in body fluids, and the ease of implantation.

b. Polymethyl methacrylate (PMMA), one of the earliest polymers used for rigid gas permeable lenses. Silicone-acrylate materials now are more commonly used under trade names such as Kolfocon. Desirable properties include being nontoxic, permeable to oxygen, comfortable to wear, and inexpensive. Also desirable is the ability to conform to the shape of the eye and to be easily cleaned.

c. Hard contact lenses are typically made of PMMA, a rigid non-gas permeable plastic. The soft contact lenses that replaced them are made of silicone, which is flexible and allows oxygen to reach the eye. Because of these properties, the soft lenses tend to be more comfortable.

 

AE 6: Neutralising the Threat of Acid Rain

Source: http://www.conserve-energy-future.com/wp-content/uploads/2013/04/Deforestation_ForestDamage.jpg

1. Mammoth Cave National Park in Kentucky is in close proximity to the coal-fired electric utility plants in Ohio Valley. Noting this, the National Parks Conservation Association (NPCA) reported that this national park had the poorest visibility of any in the country.

a) What is the connection between coal-fired plants and poor visibility.
b) The NPCA reported “the average rainfall in Mammoth Cave National Park is 10 times more acidic than natural.” From this information and that in your text, estimate the pH of rainfall in the park.

Answer:

a) Coal-fire plants produce sulphur dioxide creating sulfate particles which is responsible for the poor visibility.

b) Normal rain pH is about 5-6 pH. If the average rainfall in Mammoth Cave National Park is 10 times more acidic, this means that the pH of the rainfall is 4-5 pH.

2.Here are examples of what an individual might do to reduce acid rain. For each, explain the connection to producing acid rain.

a) Hang your laundry to dry it.
b) Walk, bike, or take public transportation to work.
c) Avoid running dishwashers and washing machines with small loads.
d) Add additional insulation on hot water heaters and pipes.
e) Buy locally grown produce and locally produced food.

Answer:

a) Water evaporates from the clothes which in turn produces water vapour. H2O combines with SOx and NOx in the air to produce H2SO4 and HNO3 (Acid rain).

b) Public transportation produces NOx from the exhaust which dissolves with H2O in the air to form HNO3 which in turn contribute to the possibility of acid rain.

c) The amount of electricity needed to run dishwashers and washing machines does not change with the amount of load. As such, more fuel is required to run the machines and in turn produces compounds which contribute to the formation of acid rain.

d) With additional insulation on hot water heaters and pipes, this increases the efficiency of the heat systems as there will be lesser heat loss to the surroundings. As such, lesser fuel is required to compensate for the negligible heat loss.

e) Buying local food, this amounts to lesser import by plane or ships. This results in less fuel burnt to run the planes and ships and thus, reducing the chance of acid rain formation.

3. a). Give names and chemical formulas for five acids and five bases.
     b). Name three observable properties generally associated with acids and bases.

Answer:
a)

Acid

Base
Hydrochloric Acid (HCl) Ammonia (NH3)
Sulphuric Acid (H2SO4) Sodium Hydroxide (NaOH)
Nitric Acid (HNO3) Magnesium Hydroxide (Mg(OH)2)
Phosphorus Acid (H2PO4) Ammonium Hydroxide (NH4OH)
Sulphurous Acid (H2SO3)

Calcium Hydroxide (Ca(OH)2)

b)
1. Acids turn blue litmus paper red.
2. Bases turn red litmus paper blue.
3. When acid reacts with an active metal, effervescence is observed and gas evolved will extinguish a lighted splint with a ‘pop’ sound.
4. Bases feel slippery and soapy.

4. The concerns of acid rain vary across the globe. Many countries in North America and Europe have websites dealing with acid rain. Either search to locate one (“Canada, acid rain”) or use these links to websites in Canada, the UK, or Europe. What are the issues in Singapore? Does the acid deposition originate outside or inside the Singapore’s borders?

Answer:

In the course of pursuit for industrialization to reach a level of development, many Asian nations emphasized on economic development, coupled with the high rate of population growth stemming from an already large population base, guarantees that SO2 and NOx emissions will increase significantly. This is because technology is emerging at a rapid rate, cutting the need for manpower and in turn, increasing the usage of machines.

As atmospheric contaminant are able to be transported over a long distance before it is being deposited, atmospheric pollution and acidification in Asia is a cause of concern to the Singapore Environment.

So many layers in the skies

Image result for different layers of ozone
Source: https://yayforcleanair.wordpress.com/ozone-depletion/

Today I learned that there are actually so many different types of ozone layers and that each of them has their unique properties and functions. It took me by surprise to realize that the Ozone itself can be a pollutant if they are on ground level. I thought it had a sole purpose of protecting us.

Ozone Screen or Ozone Layer?

The term “ozone layer” is often referred by people as a covering of ozone surrounding Earth but the term does not have a functional meaning to it as people may not necessarily know it actually serves the purpose of protecting the earth from harmful radiation. But apart from the function, what is the mechanism behind it’s protective “screening” ability?

Ozone can absorb highly energetic and harmful UV-B and UV-C light and hence break into oxygen atom and oxygen molecule, effectively absorbing the harmful radiation. The oxygen atom reacts with oxygen molecule to form ozone again making it ready to absorb UV radiation again, hence the cycle repeats it self.

 

The Oh-zone Layer

The ozone layer is depleting faster that it is replacing. Actions need to be taken in order for a more environmentally friendly world to live in. Meanwhile, manufacturing of new products to reduce ozone depletion are in place hopefully for a better future.ways-to-bring-down-ozone-layer-depletion

Protecting the Ozone Layer

The ozone layer is a deep layer in the stratosphere that has large amounts of ozone in it. The layer shields the entire Earth from much of the harmful ultraviolet radiation that comes from the sun.

Ozone is a special form of oxygen, made up of three oxygen atoms rather than the usual two oxygen atoms. It usually forms when some type of radiation or electrical discharge separates the two atoms in an oxygen molecule (O2), which can then individually recombine with other oxygen molecules to form ozone (O3).

Source: https://upload.wikimedia.org/wikipedia/commons/4/46/Future_ozone_layer_concentrations.gif

 

 

Ozone formation

The first step to ozone formation is via the ultraviolet radiation which breaks apart a molecule of oxygen (O2) into 2 oxygen atoms (2 O).

Secondly, each of these highly reactive oxygen atoms combines with an oxygen molecule to to produce an ozone molecule (O3)

ozone_4