CM8001 -Application exercise 9 – 5/04/17

1. In allergy sufferers, histamine causes runny noses, red eyes, and other symptoms. Here is its structural formula. 

a. C5H9N3


c. Amine groups as they form hydrogen bonds with water.


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 that would allow antihistamines to compete with histamine. 

When you get injured or when your immune system detects a potentially dangerous foreign  substance, certain white blood cells and tissue cells release histamines that seek out and attach to other cells that have a histamine receptor.

Allergies occur when your immune system erroneously thinks an innocuous foreign substance, such as pollen or pet dander, is dangerous. Histamines jump to action, causing a range of symptoms associated with allergies (sneezing, itchy eyes, chest congestion, wheezing, etc.).

Hence, antihistamines are typically used to ease allergy symptoms by competing with histamine to bind to histamine receptors, this prevents histamine from further eliciting the physiological changes, easing allergy symptoms.

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? 

(a) aspirin (b) morphine (c) Keflex antibiotic (d) estrogen (e) amphetamine (f)penicillin

Produce physiological response: A, B, D, E

Inhibit growth of substances that cause infections: C, F


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? 

Supported by many research studies done by TCM practitioners, the product does not contain prohibited ingredients and does not make claims to treat diseases. Packaging contains sufficient evidence and information for consumers to read when purchasing or using.

Some compounds in the products are also tested by healthcare professionals. They showed that herbal medicines do not interact with Western medicine.

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

They can be sold without license but dealers are advised to comply to guidelines for health/herbal supplements set by the Health Sciences Authority. For example, it should not contain any prohibited substances, claims are accurate and truthful, product label of ingredients for consumer to read and it should be printed in a clear and legible manner.




CM8001 – Application Exercise 7 – 24/03/17

1. When Styrofoam packing peanuts are immersed in acetone (the primary component in some nail-polish removers), 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. Hint: Remember that Styrofoam is made with foaming agents.

Styrofoam is made from random orientation addition polymers. When immersed in acetone, the polymers are rearranged into a crystalline structure with H to T arrangement so it is 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.

Not enough effective inter-molecular bonding due to less surface area, material not as strong and may be cut through.

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

HDPE is more spread out, has more surface area for london dispersion forces to attract each other polymer more strongly, and it is thus more resistant to being cut – Stronger inter-molecular forces.

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.

No. Atoms in paper are unable to slide over one another and stretch when a force is applied, due to the type of inter-molecular forces – covalent bonding restriction. It cannot stretch and will break immediately after a great force is applied.

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

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

2) Non-Toxic
4) Fast & Flexible

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 restore 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.

The properties of an ideal polymer for contact lenses include:
Water absorbing that has water current to transmit oxygen to eye through lens.
The difference in material depends on the type of polymer being used. The polymers are different because it contains nitrogen atoms in its structure unlike PMMA which does not contain nitrogen. Polyacrylamide is similar to the polymers used to make acrylic fibres for fabrics. When the polyacrylamide chains are cross-linked, the material absorbs water. Substances such as this are called hydrophilic.

The differences in properties can keep the lens soft and flexible. However, the high water content also makes the lens more fragile and reduces clarity of vision.

CM8001 – Application Exercise 6 – 16/03/17

1.Mammoth Cave National Park in Kentucky is in close proximity to the coal-fired electric utility plants in the Ohio Valley. Noting this, this 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?
Burning of coal will result in forming smoke, dust and particulate matter that block out sunlight. Sulphur emission from burning coal form tiny droplets which form aerosols. Aerosols reflect sunlight instead of absorbing, this reduces 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.
SO dissolves in rainwater to form acid. Natural rain has pH of 5.3 so the SO2 released from the burning of coal would make the rain more acidic with a  pH of 4.3 


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

a. Hang your laundry to dry it.
Bases from detergent evaporate, neutralize acid

b. Walk, bike, or take public transportation to work.
Less NOx emissions from cars/vehicles

c. Avoid running dishwashers and washing machines with small loads.

Less hot, less places for N2 and N02 to react to form NO

e. Buy locally grown produce and locally produced food.

Reduce the need to import food hence reducing the need for transportation so less pollutants are emitted.


3a. Give names and chemical formulas for five acids and five bases.


Hydrobromic acid (HBr)

Phosphoric acid (H3PO4)

Sodium hydroxide (NaOH)

Potassium hydroxide (KOH)

Magnesium hydroxide (Mg(OH)2)


b. Name three observable properties generally associated with acids and bases.

Acids: Conduct electricity in aqueous solution, taste sour, turn blue litmus paper red

Bases: Conduct electricity in aqueous solution, taste bitter, turn red litmus paper blue


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?

Half of the acid deposition in eastern Canada came from American sources while the other half from its own country. Within Canada, there were domestic agreements starting with a declaration signed by the federal government and the seven provinces in establishing the Eastern Canada Acid Rain Program.  The goal was to limit deposition of sulphate precipitations to less than 20kg per hectare each year. Provinces agreed to cap SO2 emissions at 2.3 million tonnes in order to achieve the 20kg limit. To address the other half  of deposition of sulphates, Canada and U.S signed a bilateral agreement called the Canada-US air quality agreement to solve the transboundary air pollution problem. Both countries had to work together to reduce SO2 and NOx emissions. Since the 20 kg/ha/yr deposition target under the Eastern Canada Acid Rain Program could only protect moderately sensitive lakes, a new program was established – The Canada-Wide Acid Rain Strategy for Post-2000. All 26 federal, provincial and territorial Ministers of Energy and Environment had to commit to reducing  SO2 emissions in order to protect lakes and forests and improve human health. They strive to achieve a deposition level of 8kg/ha/year.

It originates both inside and outside of Singapore. There is definitely acid deposition in Singapore due to our high amount of vehicles producing NOx and power stations, refineries, other industries such as oil fuel companies releasing SO2 into the environment. However, acid deposition in Singapore is worsened when there is excessive burning of forests in Indonesia. The wind patterns can bring in the acid deposition resulting in haze within Singapore.






CM8001 – Application Exercise 5 – 22/02/17

1.How can you purify your water when you are hiking? Name two or three possibilities. Compare these methods in terms of cost and effectiveness. Are any of these methods similar to those used to purify municipal water supplies? Explain.
1) Boiling Water in a pot over a fire
2) Filtration
3) Tablets (Water Purification) Eg. Chlorine / Iodine

However, these cost saving methods does not remove toxic substances & cryptosporidium.

These methods are similar to those being used to purify mineral water but without more toxic substances + contamination + testing of the substances are done before it is discharged to public.

2.Explain why desalination techniques, despite proven technological effectiveness, are not used more widely to produce potable drinking water.
It requires a huge amount of energy to distill very little amount of pure water. In addition, there are still a lot more of impurities in water such as bacterial and organisms and unwanted chemicals, as a result, the water has to go through treatment.
As such, the water treatment cost will become costly and high pressure equipment requires a lot of energy.

3.Water quality in a chemical engineering building on campus was continuously monitored because testing indicated water from drinking fountains in the building had dissolved lead levels above those established by NEA.

a. What is the likely major source of the lead in the drinking water?
Corroded pipe, rust.

b. Do the research activities carried out in this chemistry building account for the elevated lead levels found in the drinking water? Explain.

No. Waste water pipes and water supply pipes are independent. Also, before water is discharged to public for drinking, levels of contaminants will be checked.

4. Some vitamins are water-soluble, whereas others are fat soluble. Would you expect either or both to be polar compounds. Explain.

Water-soluble vitamins have polar groups hence they are polar, they can undergo hydrogen bonding with water.
Fat-soluble vitamins are non-polar, they can only dissolve in non-polar solvents.


CM8001 – Application Exercise 4 – 15/02/17

1. Understanding Earth’s energy balance is essential to understanding the issue of global warming. For example, the solar energy striking Earth’s surface averages 168 watts per square meter (W/m^2), but the energy leaving Earth’s surface averages 390 W/m^2). Why isn’t Earth cooling rapidly?

Some heat energy trapped by clouds and atmosphere, even though it is reflected off earth’s ground surface.

2. Decide and explain whether the statement is correct or incorrect. Explain.

Incorrect.The extreme winter is a result of global warming which should be a cause of concern as more extreme winters will have devastating consequences on traffic/temperature/crops etc.

3. One of the first radar devices developed during World War II used microwave radiation of a specific wave range that triggers the rotation of water molecules. Why was the design not successful?

The radiation warms up drinking water/liquid items unnecessarily. Food gets cooked/ might explode (eggs) due to the heat energy.

4. Now that you have studies air quality (Unit 1), stratospheric ozone depletion (Unit 2), and global warming (Unit 3), which do you believe poses the most serious problem for you in the short run (pick one and explain)? In the long run (Pick one and explain why)?
Short run – Air quality as it affects health directly like respiratory issues. Also affects road/air traffic vision.
Long run – Ozone depletion as it is a cause of global warming as well. Causes serious medical issues in the long run like skin cancer due to increased and more intensive exposure.

CM8001 – Application Exercise 3 – 08/02/17

Question 1: From personal experience, state whether these processes are endothermic or exothermic. Give a reason for each.

A. Exothermic, gives out heat

B. Endothermic, takes heat in to evaporate

C. Endothermic, takes in heat to melt

Question 2
Chemical explosions are very exothermic reactions. Describe the relative bond strengths in the reactants and products that would make for a good explosion.

Bond breaking that occurs in an reactant would be Endothermic, whereas bond formation that occurs in an reactants would be Exothermic.

To produce a good explosion, the bond strength of the products should be much stronger as compared to the reactants.

y are released.


Question 3:
How might you explain the difference between temperature and heat to a friend? Use some practical, everyday examples?
An object with no heat energy still has a temperature of 0K (Kelvin). Temperature is a measure of heat inside a medium.
Heat is measure of temperature transfer from warm to cold area.
An oven set at 200°C provides heat energy to food to raise its temperature to 200°C

– In a situation of a unfortunate event where a person burn his skins from a cup of hot water, the area of the skin where the hot water touches will experience burning sensation. This is due to the presence of heat / heat content. As heat is a form of energy, it flows from a point of higher temperature to a lower temperature
( If you put your hand into hot water, you will feel hot, this is due to the presence of heat)
*Cold water – lack of heat, feels cold.


Question 4:
A premium gasoline available at most stations has an octane rating of 98. What does that tell you about:

The knocking characteristics of this gasoline?
a) 98% is octane and 2% heptane

Whether the fuel contains oxygenates?
b) might contain premium gasoline and expensive due to addition of oxygenates which are costly. The octane rating is also relatively high so it is possible that it is enhanced.
Might not contains oxygenates usually for gasoline with octane ratings exceeding 100.


Group 7 Topic!