CM8001 Group 9 Pollution Rises, Acid Rain Falls Tue, 29 May 2018 17:21:22 +0000 en-US hourly 1 Application Exercise 9 Thu, 05 Apr 2018 06:53:37 +0000
  • In allergy sufferers, 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

    (      runny-noses-red-eyes-symp-chapter-10-problem-9q-solution-9780077418465-exc)

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

    The N-H Bonds

    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. Here is the      structure for a particular antihistamine

    (a) Give the chemical formula for this compound


    (b) What similarities do you see between this structure and that of histamine that          would allow the antihistamine to compete with histamine?

     Both compounds have presence of N-C-N bonds

    3. Consider this statement. “Drugs can be broadly classes 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?

    Physiological response in the body: Aspirin, morphine, estrogen,     amphetamine 

    Inhibit growth of substances that cause infections: (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 manufactureres that address these issues?

    But since they became widely available in 1994, the FDA and some independent researchers have found problems with some dietary supplements. Products like herbs are sometimes tainted with germs, pesticides, or toxic heavy metals. Other supplements do not contain what’s listed on the label. Still others contain more or less than the amount of the herb listed on the label. And many have ingredients that aren’t listed on the label at all.

    This problem extends beyond the supplement makers and sellers. Some herbal suppliers (those who grow, harvest, or sell the crops) may mix or even substitute their crops with less expensive or more readily available plants. There’s also the problem of accidental contamination, when one plant grows in with others, as well as cases of mistaken identity (when one plant looks like another). Given the global market, all of these problems can make it harder for a company to be sure that what they thought they were buying to make supplements is actually the herb they wanted.

    In 2013 researchers in Toronto published a report in which they sampled and analyzed 44 herbal supplements. The supplements were sold in both the US and Canada, and labeled as containing single herbs. Using DNA bar coding analysis, less than half the supplements (48%) contained any of the herb listed on the label. More than half of the supplements contained something that wasn’t on the label (substitutions or fillers). Even among the samples that contained the herb on the label, many also contained fillers or contaminants.

    (b) Do you know anything about Singapore’s Legislation on the topic.

    Singapore’s legislation encourage product to label its basic supplemental facts:

    (1) Name of health supplement product

    (2) Names and quantities of active ingredients

    (3) Product indications and intended purpose

    (4) Recommended daily dosage

    (5) Instructions on proper usage

    (6) Pack size

    (7) Batch No

    (8) Expiry Date

    (9) Names on inactive ingredients

    (10) Name and address of manufacturer and packer

    (11) Name and address of dealers

    (12) Precautionary label and statement when necessary. 

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    Application Exercise 22nd March 2017 Wed, 22 Mar 2017 06:44:32 +0000
  • 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.Gas of the foaming agent is given out when acetone dissolves the polymer. the polymer then collapses and become denser.
  • 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 flexible.a. Suggest a reason why branched LDPE cannot be used in this application.

    LDPE cannot be used in this application as it does not have the required strength.

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

    The molecules of HDPE must line up in a way that produces the required strength. Using a thin liner of HDPE allows sufficient flexibility.

  • Why you try to stretch a piece of plastic bag, the length of the piece of plastic bag 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.When the piece of plastic is stretched, the strip narrows and “necks down”. The molecules become aligned parallel to each other and in the direction of the pull. This alteration of the 3D structure is not reversible, and if the pulling continues, the plastic breaks. When the same pulling force is applied a piece of paper, the paper tears rather than stretching to any significant extent. The cellulose molecules in paper are held far more rigidly in place, and are not free to become aligned.
  • 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.

    The benefits for polymers intended for use in the body should far outweigh any risks. The two main properties are (1) stable over time of intended use and (2) non-toxic. Other factors to consider are low cost, lack of solubility in body fluids, lack of reactivity in body fluids, and the ease of implantation.

    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.

    Several different types of contact lenses are on the market and each uses a different type of polymer. Polymethyl methacrylate (PMMA), one of the earliest polymers used for rigid gas permeable lenses, is structurally similar to Lucite and plexiglas. Silicone-acrylate materials now are more commonly used under trade names such as Kolfocon. Newer rigid gas permeable (RGP) polymers contain fluorine: fluoro-silicone-acrylate polymers and fluoro-silicones. Polymacon (38% water) is typical of the polymers used for soft lenses and is a polymer of 2-hydroxyethyl methacrylate (HEMA). Other methacrylates include hioxifilcon (48% water) and methafilcon (55% water) or even lidofilcon (70% water). Manufacturers’ websites are good sources of information. 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 (if not disposable).

    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?

    As mentioned in the previous part, 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.

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    Application Exercises 15th March 2017 Wed, 15 Mar 2017 06:54:41 +0000
  • Mammoth Cave National Park in Kentucky is in close proximity to the coal-fired electric utility in the 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?Coal-fired plants release sulphur dioxide, creating sulphate particles theatre responsible for 60 – 85% of poor visibility in eastern parks.b. The NCPA 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.Normal rain has a pH range of 5 – 6. If the rainfall in the park is 10 times more acidic, the pH range must be in the range of 4 – 5.
  • Here are some 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.Requires less energy than using a clothes dryer. For an electric dryer cutting down on energy use cut down on the needs of power companies to produce electricity by burning coal.b. Walk, bike, or take public transport to work.

    Amount of NO emitted in the air is reduced. Hence, reducing acid rain.

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

    By washing dishes in the traditional way and using washing machine to wash the full load instead of small loads for a few times help to reduce the need of electricity, hence reducing the need of power-supply plant to burn coal which may contain sulfur.

    d. Add additional insulation on hot water heaters and pipes.

    Improve energy efficiency.

    e. Buy locally grown produce and locally produced food.

    There will be less need to import overseas grown and produced food. Thus, reducing the needs for transportation of goods and reducing NO.

  • a. Give names and chemical formulas for five acids and five bases.
    5 acids: Hydrochloric acid (HCl), Nitric acid  (HNO3) ,Carbonic acid (H3CO2), Hydrogen Bromide (HBr),Sulfuric acid (H2SO4)
    5 bases: Sodium hydroxide (NaOH),Ammonia ( NH3 ),Calcium hydroxide ( Ca(OH)2  ), Lithium hydroxide (LiOH), Potassium Hydroxide (KOH)b. Name three observable properties generally associated with acids and bases.Acids: taste sour, turn blue litmus paper red, corrosive to metals such as iron and aluminium
    Bases: soapy feeling, taste bitter, turn red litmus paper blue
  • 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?Power plants in Singapore (coal, oil and gas) release sulphur into the atmosphere, which is extremely poisonous. Sulphur can mix into the clouds and dissolve into the rain, which produces acid rain. It is very dangerous as it corrodes many rocks and materials which is also harmful to lakes and rivers.Corrode buildings overtime in Singapore and cause drinking water to be acidic. Acid deposition in soil will harm trees and plants, leading to loss of habitat for some animals.Can be originated from both within Singapore borders or pollutants from other countries can be transported by wind and cause acid rain

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    Application Exercises 22nd Feb 2017 Wed, 22 Feb 2017 07:06:24 +0000
  • How can you purify your water when you’re are hiking? Name 2 or 3 possibilities. Compare these methods in terms of cost and effectiveness. Are any of these methods similar to those used to purify municipal water supplies?

    Boiling water can be used as it is the most certain way of killing microorganisms. Potable Aqua Iodine and clear plastic bottle in sunlight to let UV rays kill bacteria can also be used. Boiling water is a cheaper alternative. Potable Aqua Iodine is the fastest way but have to be purchased from outdoor activity stores. Chlorine tablets are used as well.
  • Explain why desalination techniques, despite proven technological effectiveness, are not used more widely to produce potable drinking water.

    The 2 most common desalination techniques are distillation and reverse osmosis. Both of these require energy to remove salts from seawater or brackish water, and thus inherently are expensive. For example, membrane distillation requires about 14kwh of energy to produce 1000 gallons of desalinated water. Hence, high amount of energy and electricity is used. If a less expensive option is available, such as hauling fresh water from a distance, then this option is used.
  • Water quality in a chemical engineering building on campus was continuously monitored because of 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?The likely source of lead is from solder in the pipe joints or from lead pipes themselves.

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


    Research activities should not contribute to the lead in the drinking water, assuming that any lead compounds are not dumped down the drain.Although many undergraduate chemistry experiments used to use lead compounds, most now have been redesigned to avoid it and other toxic metal ions. Recall that substances dumped into a sewage treatment system may end up downstream in someone else’s drinking water.

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

    Both can be polar compounds. Fat soluble vitamins, such as Vitamin A, are mostly non polar, hydrophobic molecules. As a result, they tend to be absorbed into fatty tissues and stored there. In contrast, water-soluble vitamins, such as Vitamin C, are polar, hydrophilic molecules that circulate in the blood and intracellular fluids, which are primarily aqueous. Water-soluble vitamins are therefore excreted much more rapidly from the body and must be replenished in our daily diet. A comparison of the chemical structures of Vitamin A and Vitamin C quickly reveals why one is hydrophobic and hydrophilic.
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    Application Exercises 15th Feb 2017 Wed, 15 Feb 2017 07:20:13 +0000
  • Understanding the 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/m2), but the energy leaving Earth’s surface averages 390 W/m2. Why isn’t Earth cooling rapidly?
    Some of the energy emitted from the Earth’s surface goes directly out to the space, while most of it doesn’t. The clouds and gases in the atmosphere reabsorb the emitted energy, causing some of it to be redistributed by convection. Condensation allows more energy to be released into the atmosphere. Greenhouse gases such as carbon dioxide, methane, nitrous oxide, ozone and water vapour reabsorbed most of the energy. To keep Earth a habitable temperature for survival, greenhouse gases frequently emit Sun’s energy back into the atmosphere. The energy that does not leave Earth’s surface is responsible for global warming. Even though the amount of energy emitted is more than double of the amount received, Earth does not cool rapidly because the atmosphere retains much of the emitted heat energy.
  • Decided explain where the statement is correct or incorrect. Explain.Incorrect.
    Experiencing winter does not necessarily mean global warming is resolved.
    Moreover, the cartoon suggested a harsh winter instead of a normal winter. The harsh winter may be suggest an increased concern for global warming.This is because, when global warming causes the ocean to heats up and melt the arctic ice. Releasing warm air in the process. Warm air destabilises the polar ice and will send cold blasts into the atmosphere.

    Thus, when global warming increases, it heats the ocean, causing freezing winters to be inevitable.

  • One of the first radar devices developed during World War 2 used microwave radiation of a specific wave range that triggers the rotation of water molecules. Why was the design not successful? 

    The absorption of microwave radiation by water in the atmosphere interferes with the detection of intended objects.

  • Now that you have studied 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 1 and explain why)?
    In the short run, air quality (Unit 1) poses the most serious problem. This is because all living things breathed in the air immediately and thus the effects of poor air quality will be felt right away. Air quality can be easily changed in the short run, by implementing different measures.In the long run, global warming (Unit 3) poses the most serious problem. It has more sustained effects in the long run. When measures to target global warming are implemented, the effects will not be shown immediately. It requires a longer time frame to minimise the effects of global warming. Furthermore, global warming cannot be resolved completely.


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    Application Exercises 8th Feb 2017 Fri, 10 Feb 2017 12:17:18 +0000
  • From personal experience, state whether these processes are endothermic or exothermic. Give a reason for each.
    a) A charcoal briquette burnns
    b) Water evaporates from your skin
    c) Ice melts
    a) Exothermic. Burning of charcoal releases heat to surroundings.
    b) Endothermic. Water needs to absorb the heat from the skin for evaporation to occur.
    c) Endothermic. Ice requires energy to be absorbed to break the lattice structure to melt.icecubemelting-554169
  • Chemical explosions are very exothermic reactions. Describe the relative bond strengths in the reactants and products that would make for good explanation.
  •               C2H6 + 3.5 O2  ——-> 2 CO2 + 3 H20
    The above equation states a complete ethane explosion.
    Given that the bond energies for reactants and products are :
    C-H bond : 411 kJ/mole
    O=O bond : 498 kJ/mole
    H-O bond  : 459 kJ/mole
    C=O bond  : 803 kJ/mole
    C-C bond : 346 kJ/mole
    The reactants will have energy level of 4555kJ/mole, while the products will have a higher energy level of
    This give an overall net energy of -493 kJ/mole, which indicates the explosion of ethane is an exothermic reaction.


    3. How might you explain the difference between temperature and heat to a friend? Use some practical everyday examples?

    Heat refers to the TOTAL energy of molecular motion inside a substance and exists as an energy that can be transferred from one to the other. While temperature is a measure of AVERAGE kinetic energy present in molecular motion of the substance and cannot be transfer.
    For example , a hot water bath of 37 degrees celsius is prepared by a person. When the person is inside the bath, we say that the heat energy of the hot water is transferred to the person’s body. While we can say that the temperature ,which is a measure of average kinetic energy of molecules in the water, is 37 degrees celsius.


             4. A premium gasoline available at most stations has an octane rating of 98. What does that tell you about :
                a) the knocking characteristics of this gasoline
                b) whether the fuel contains oxygenates

    a) This states that the gasoline contains 98% iso-octane and 2% heptane. It will be unlikely for the gasoline to cause much knocking to the engines.
    b) The octane rating does not tells us whether the fuel contains oxygenates.





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    Particulate Matter Wed, 25 Jan 2017 07:56:23 +0000 img_0987

    Particulate Matter is a mixture of solid particles and liquid droplets. It can be classified into 2 groups, PM2.5 and PM10. The difference between them is the measurement of particle size. PM2.5 refers to particles with size of less than 2.5 μm while PM10 refers to particles with size of less than 10 μm. Hence, with a smaller size, PM2.5 particles implicates heart diseases while PM10 particles affects the lungs.

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    Hello world! Tue, 24 Jan 2017 08:06:45 +0000 Welcome to Open Source Studio. This is your first post. Edit or delete it, then start blogging!

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