Category Archives: The Impact of Chemistry on Society

My Work, Research

CM8001: AE9 Answers

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1a) C5H9­N3

1b)

1c) The amine functional group makes the compound water-soluble as it is polar.

2a) C16N3H21

b) Both are amines. The histamine in question 1 is primary, while this histamine is secondary.

3) Drugs that produces a physiological response in the body : Aspirin, morphine, estrogen, amphetamine. Drugs that inhibit the growth of substances that causes infections: (Keflex) Antibiotic, penicillin.

4a) Herbal supplement are regulated by FDA not as drugs but as dietary supplements. In June 2012, FDA sued New Jersey-based Quality Formulation Laboratories as they produced protein powder mixes and other supplements in a facility infested with rodents, rodent feces and urine, according to government records. FDA inspectors found a rodent apparently cut in half next to a scoop, according to a 2008 inspection report. (http://www.chicagotribune.com/lifestyles/health/ct-met-supplement-inspections-20120630-story.html)

4b) In Singapore, there are certain acts to deal with herbal or alternative medicines such as the Traditional Chinese Medicine Practitioners Act and Health Products Act. The Traditional Chinese Medicine Practitioners Act is an act to provide for the registration of traditional Chinese medicine practitioners and for purposes connected therewith. (http://statutes.agc.gov.sg/aol/search/display/view.w3p;page=0;query=DocId%3A51647f4d-2ca6-4557-95da-bda6099f2345%20Depth%3A0%20ValidTime%3A31%2F12%2F2001%20TransactionTime%3A31%2F12%2F2001%20Status%3Ainforce;rec=0;whole=yes) The health products Act is an act to regulate the manufacture, import, supply, presentation and advertisement of health products and of active ingredients used in the manufacture of health products and provide for matters connected therewith. (http://statutes.agc.gov.sg/aol/search/display/view.w3p;page=0;query=DocId%3A1aeaf39a-c2b6-4c46-9b90-a1a8141e3f5f%20Depth%3A0%20ValidTime%3A10%2F08%2F2010%20TransactionTime%3A31%2F12%2F2008%20Status%3Ainforce;rec=0;whole=yes)

Research

CM8001: AE7 Answers

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1) The styrofoam holding the peanuts have a lot of air spaces between the groups of polymers as the polymer is made as a foam. Acetone dissolves the Styrofoam, removing the air spaces and thus making the styrofoam much denser.

2a) LDPE cannot be used in this application because it does not have the required strength as compared to HDPE.

2b) The molecules of HDPE must line up in a way that produces the required strength. Thus, using a thin liner of HDPE allows sufficient flexibility.

3) When stretched, the molecules align parallel to each other in the direction of the fool. This change in the structure in not reversible and if it continues, the plastic breaks. The same does not apply to paper since the molecules in paper are held more rigidly thus preventing it from aligning with each other.

4a) Not soluble in body fluids, easy to implant it in the human body, stable over time of use and non toxic.

4b) Contact lens are made from poly(methylmethacrylate) (PMMA). The materials should be permeable to oxygen, comfortable to wear, nontoxic and inexpensive.

4c) Hard contact lenses are usually made of PMMA while soft contact lenses are made of silicone. Soft contact lenses are more comfortable as PMMA is more rigid and does not allow gas to permete while silicone are more flexible and allows for oxygen to reach the eye.

Research

CM8001: AE 6 Answers

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1a) Coal plants release huge amounts of water vapor during the combustion process of the coal. Water vapour when cooled becomes visible as fog.

1b) pH of rainfall in the park is pH 6 as the pH scale is logarithmic.

3a)

Acids Bases
HCL (Hydrochloric acid) NaOH (Sodium Hydroxide)
H2SO4 (Sulfuric Acid) Ca(OH)2 (Calcium Hydroxide)
HNO3 (Nitric Acid) NH4OH (Ammonium Hydroxide)
H2CO3 (Carbonic Acid) Mg(OH)2 (Magnesium Hydroxide)
HBr (Hyrdrobromic Acid) CsOH (Cesium hydroxide)

3b)

Acids
Turns blue litmus paper red.
Reacts with carbonates to form CO2.
pH<7
Bases
Soapy Feel
Turns red litmus paper blue.
pH>7

4) Acid deposition is problematic especially in the region of eastern Canada because waters and soils in those region lacks natural alkalinity and therefore cannot neutralize  acid naturally. Canada has since cap Sulfur Dioxide to 2.3 million tonnes in the seven eastern most provinces and has also negotiated with the United States to cut sulfur and  and nitrogen oxides emission. In Singapore, acid rain is generally not a concern due to the good air quality that Singapore enjoys. However, acid rain may be more of a concern during the hazy seasons. The haze problem in Singapore normally originates from Indonesia as the government are incapable of monitoring their own citizens to prevent them from illegally adopting the slash and burn practices thereby causing air problems to countries all around them. Therefore we can say that the acid deposition originate, if any, originates from outside of Singapore.

Research

CM8001: AE 5 Answers

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1. Tie a plastic ziplock bag on to a big leaf with direct sunlight. It is definitely cost effective but it may take a longer period of time. It is similar to distillation method as water vapour produced from the respiration of the leaf will condensed on the cooler surface of the plastic, and water droplets will form upon the loss of energy from the vapour molecule, resulting in the change in phase. This water droplet will then accumulate within the plastic ziplock bag as purified water. We can also use water purification tablets which are chlorine dioxide tablets to make potable water.

2. Cost is high to build the plant. Additionally, the cost is also relatively high to produce a small amount of water. Large amount of land is also needed so countries that cannot afford to provide such land space may not be able to use desalination technique to purify water. Desalination technique is also not suitable for landlocked countries.

3a. Corrosion of plumbing system from pipes and erosion of natural deposits.

3b. There could be a possibility of that happening but the chances are low as such chemical plants will have strict regulations to prevent such contamination to occur.

4. Fat soluble vitamins have few or no polar groups while water soluble vitamins have more polar groups than non polar groups which can form hydrogen bonds with  water molecules.

Research

CM8001: AE4 Answers

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  1. The energy that leaves the Earth’s surface as radiation is absorbed via the greenhouse gases present in the atmosphere. Thus, the energy is retained within the atmospheric layer instead of actually leaving the Earth as “loss of energy”.
  2. Global warming will make winters colder. The worsened global warming will increase the precipitation because the atmosphere can hold more moisture. There will be an increase in cold air and water vapour, and therefore, an increase in snow; the statement is incorrect.
  3. Our group’s assumption is that the absorption of microwave radiation by water in the atmosphere interferes with the detection of intended objects, or that it was necessary to shield the radar to protect people around it from harmful microwaves that could interact with the water in their bodies.
  4. Air quality is the most vital. Although all are important in the long run, we can feel the effects on our health immediately, like the scenario in Beijing at the moment. Global warming and ozone depletion take time to worsen.
Research

CM8001: AE 3 Answers

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1a. Charcoal briquette burning is an exothermic reaction. It produces heat, from personal experience.

1b. Endothermic reaction, as heat is absorbed for water molecules to gain energy and eventually gain sufficient energy to leave the water surface as a gas molecule, which is water vapour. Thats why we feel cool when we sweat.

1c. Endothermic reaction, it requires heat is absorbed for ice molecules to gain kinetic energy and eventually gain sufficient energy to become a water molecule.

2. The starting reactants have much more energy than the products. Exothermic reactions need only release energy to the surroundings by converting chemical potential energy into kinetic energy. Therefore, for a good explosive, the bonds of the reactant is much stronger that the product ones.

3. Heat is why you feel hot or cold, and temperature is just the measurement of the average kinetic energy of the molecules. The room feels warmer, due to the heat energy in the room – the temperature is 25 degrees celsius.

4a. The quality of the gasoline is higher, the higher the rating the lower the knocking. Less impurities inside. It has 98 percent of isooctane and 2 percent of heptane.

4b. higher rating means more oxygenates. so it has a relatively high percentage of oxygenates. Thus, more complete combustion, and less pollutants.