C5H9N3

b) Circle the amine functional groups in histamine

NH2, N and HN

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

The “salt” end.

2) a) Give the chemical formula for this compound

C16H21N3

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

They share a sequence of N-C-N atoms and a 2 Carbon chain with Nitrogen at the end. Another similarity is how these sequences are placed. Also, the antihistamine has a flat 6-ring, similar to the flat 5-ring of histamine.

The antihistamine would block histamine action by binding more tightly to histamine receptor sites on cells than histamine.

3)

• Aspirin – Physiological Response
• Morphine – Physiological Response
• Antibiotic – Inhibit the Growth of Substances
• Estrogen – Physiological Response
• Amphetamine – Inhibit the Growth of Substances
• Penicillin – Inhibit the Growth of Substances

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

There are dietary supplement labels the contents and ingredients, and the amount of each inside every supplement. Also, you are advised to listen to your health care provider (e.g. doctor) to decide what amount of supplement you should be taking, instead of jut following the suggesting serving size.

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

From the Ministry of Health: https://www.moh.gov.sg/content/moh_web/healthprofessionalsportal/tcmpractitioners.html

The Health Sciences Authority (HSA) regulates all Chinese Proprietary Medicines in the tablet, capsule, etc. form. Before they can be sold in Singapore, they must comply with quality and safety criteria. HSA will also license dealers of these products.

Date: 15 March 2017

Location: Outside LT24

Duration: 1 hour

Attendance: Full

Topics Discussed: How we are going to split the work for our blog, and what content we should put inside.

Tasks to be done: Ben and Zi Kang to focus on the Chemical Concept of Polymers, while Joel, Melvin and Timothy to focus on Implications on Society.

Date: 22 March 2017

Location: Outside LT24

Duration: 1 hour

Attendance: Full

Topics Discussed: Finalization of blog contents/format

Tasks to be done: All members to brainstorm ideas for the videos for further discussion the next week.

Date: 29 March 2017

Location: SPMS Tutorial Room

Duration: 2 hours

Attendance: Full

Topics Discussed: What software to use when creating the video, content that should be put into the video and how we should create the video. Then we proceeded to start creating/recording the video

Tasks to be done: For all members to finish the recording and creation of the video at home, before the next week.

Date: 5 April 2017

Location: Outside LT24

Duration: 1 hour

Attendance: Full

Topics Discussed: Compilation and editing of video elements, as well as final check-through, and uploading of videos to YouTube.

Tasks to be done: Submission of Video by Ben when the links are open.

Our group will be focusing on Polymers as our chosen topic. A polymer is a large molecule or a macromolecule formed by joining many repeated subunits. They may be naturally found in plants and animals known as the natural polymers or may be man-made called the synthetic polymers. Different polymers have a number of unique physical and chemical properties due to which they find usage in everyday life.

Polymers make up of many materials in living organisms, including proteins, cellulose and nucleic acids. Moreover, they constitute the basis of such minerals as diamond, quartz and man-made materials as concrete, glass, paper etc.

Polymers make up so many things that we can find in our surroundings, one of them is our DNA where it is a polymer. Using general terms, polymers are often named as plastic. With the use of the material plastic, it is able to create many different things and types such as a shopping bag. The polymer for a shopping bag is significantly different from the polymer used to make a PVC which is different from that to make polystyrene.

Polymers are used daily in our lives, such as polystyrene which is one of the most common plastic, actively used in the packaging industry. Bottles, toys, containers etc are some of the daily-used products made up of polystyrene, where it is used as an insulator. PVC is commonly used in clothing and furniture and has been popular for the construction of doors and windows as well.

Chemical Concept

Introduction

• A polymer consists of long chain molecules, each molecule made up of repeated units connected together.
• Polymers are synthesized by many small molecules joining together into very large molecules called macromolecules. The small units called monomers, are unsaturated organic molecules.
• Polymers can be synthesised in 2 kinds of reactions: addition polymerisation and condensation polymerisation.
• In addition polymerisation, the reaction involves the formation of free radicals to initiate the polymerisation.
• Condensation polymerisation usually involves the interaction between the side functional groups, leading to the formation of by-products.
• When two or more different monomers unite together to polymerize, their result is called a copolymer and its process is called copolymerization. Fig 1 shows the possible type of co-polymers.

Fig 1: Types of co-polymers

Molecular Arrangement of Polymers chains

Fig 2: Arrangement of polymer chains

• Controlling the cooling rate of polymer melt can result in different arrangement of the polymer chains
• When quenching is used( i,e rapid cooling), an amorphous arrangement of molecules is obtained since the polymer chains do not have enough time to rearrange the chains.
• Due to the lack of arrangement, light can pass through amorphous material without being refracted, hence Amorphous polymers are generally transparent.
• On the other hand, with slow cooling, a high degree of crystallinity can be achieved. Polymers with high degree of crystallinity appears translucent and opaque since light is refracted by the regular array of crystal.

Characteristics of Polymers

Every polymer has very distinct characteristics, but most polymers have the following general attributes.

• Polymers can be very resistant to chemicals.
• Polymers can be both thermal and electrical insulators.
• Polymers are very light in weight with significant degrees of strength.
• Polymers can be processed in various ways.
• Polymers are materials with a seemingly limitless range of characteristics and colors.
• Polymers are usually made of petroleum, but not always.

References: https://plastics.americanchemistry.com/plastics/The-Basics/

Implications on Society

Introduction

Polymers are found in every corner of our modern living world and brings about immense convenience and advantages to our lives. However, there are some negative impacts of their presence. Plastic, a commonly used polymer, occupy huge volumes in landfills and pose a serious problems for all the countries in the world. Large amounts of them have been found in the oceans as well. The plastic fragments had most likely leached into the drains during rain, transported into the rivers and ultimately into the seas and oceans.

Polymers are dumped in various landfills in many countries. In the landfills, the polymers take a very long time to biodegrade. That is because of the lack of oxygen and moisture in the layers below the surface. Biodegradable polymers can be defined as polymers that can be degraded directly by the action of the enzymes under normal conditions like in room temperature or under aerobic conditions. The main degrading organisms are bacteria, fungi, archaea and even insects.

Since the polymers will be degraded one day and its components returned to the environment, precautions must be taken to not use toxic materials whilst production. We should always consider the environmental impacts from the production of the polymer to the degradation process.

Explanation

Polyvinyl chloride (PVC), one of the most commonly used plastics in the world, exceeds 35 million tonnes of usage in the world per year. It has vast applications, ranging from cables and flooring to pipes and fittings. PVC degrades easily under the action of light and heat and releases toxic substances.  In the industries, plasticizers which are based on phthalate are used to make PVC more flexible. This substance posed chronic toxicity to animals and has teratogenic effects. It also poses body growth problems and causes reproduction complications in humans. The small fragments of PVC can evaporate and rise to the stratosphere to destroy the ozone layer. During disposal, if PVC were to be incinerated, toxic products such as dioxins are produced and this poses another threat to human health.

Another common polymer is polycarbonate (PC). They are a naturally transparent amorphous thermoplastic. The advantage of using PC is that it allows for the internal transmission of light to be nearly in the same capacity as glass. PC polymers are common used to product plastic lenses in eyewear or protective gears due to its transparency. During the production of PC plastic, a chemical known as bisphenol A is used as one of its monomers. It has been shown that this chemical is toxic and poses carcinogenic effects and neurotoxicity in animals. During decomposition of the resin, these toxic monomers can be released into the environment.

Biopolymers generally have little impact on the environment. They are the polymers produced by living organisms and have been around for millions of years. The only implication it might bring about is during degradation under anaerobic conditions. This process generates biomass, methane, carbon dioxide, water and some other small molecules. The issue presented is with the methane as it contributes to the greenhouse gases. Biopolymers will act as a contaminant upon mixing with other polymers during recycling. Biopolymers are not recyclable and usually degrade during recycling processes.

References

1. http://www.intechopen.com/books/polymer-science/polymers-and-the-environment
2. http://www.pvc.org/en/p/how-is-pvc-used
3. https://www.creativemechanisms.com/blog/everything-you-need-to-know-about-polycarbonate-pc

a) What is the connection between coal-fired plants and poor visibility?

Coal-fired plants release sulfur dioxide, creating sulfate particles that are responsible 60 to 85 percent of the poor visibility in the eastern parks.

b) The NPCA reported “the average rainfall in the 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, so if the rainfall in this park is 10 times more acidic, the pH range must be 4-5.

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

Hanging laundry to dry requires less energy than using a clothes dryer. For an electric dryer, cutting down on energy use cuts down on the need for power companies to produce electricity by burning coal, reducing SO3 emissions

b. walk, bike, or take public transportation to work

Any of these options reduce the amount of gasoline used cutting down on NO emissions and thus contributing less to the acidity of rain.

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

Using dishwashers and washing machines with large loads reduces the energy per unit load, therefore needing power companies to produce less electricity by burning coal, reducing SO3 emissions

d. Add additional insulation on hot water heater and pipes

Adding insulation on hot water heater pipes reduces heat loss, as well the need for power companies to produce electricity to generate more heat by burning coal, reducing SO3 emissions

e. Buy locally grown produce and locally produced food.

Buying locally grown produce and locally produced food reduce the amount of gasoline used for food import and therefore cutting down on NO emissions and thus contributing less to the acidity of rain.

3. a) Gives names and chemical formulas for five acids and five bases.

Possibilities of acids include nitric acid (HNO3), hydrochloric acid (HCl), sulfuric acid (H2SO4), sulfurous acid(H2SO3) and phosphoric acid (H3PO4). Possibilities of bases include sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH4OH), magnesium hydroxide (Mg(OH)2) and calcium hydroxide (Ca(OH)2).

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

In general, acids turn blue litmus paper red, are corrosive to metals such as iron and aluminium, and release carbon dioxide from a carbonate. These properties may not be observed if the acid is not sufficiently concentrated. Bases turn red litmus paper blue, have a slippery feel in water, and are caustic to the skin.

4. The concerns of acid rain vary across the globe. Many countries in the 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?

The Indonesian forest fires that took place from August through October 1997 released large amounts of gaseous and particulate pollutants into the atmosphere. The particulate emissions produced a plume that was easily visible by satellite and significantly affected regional air quality in Southeast Asia. This prolonged haze episode provided an unprecedented oppurtunity to examine the effects of biomass burning on regional atmospheric chemistry. A comprehensive study assessed the influence of biomass burning impacted air masses on precipitation chemistry in Singapore. Major inorganic and organic ions were determined in 104 rain samples collected using an automated wet-only sampler from July through December 1997. Mean pH values ranged from 3.79 to 6.20 with volume-weighted mean of 4.35. There was a substantially large number of rain events with elevated concentrations of these ions during the biomass burning period. The relatively high concentrations of sulphate, nitrate and ammonium ions observed during the biomass burning period are attributed to a long residence time of air masses, leading to progressive gas to particle conversion of biomass burning emission components. The decrease on pH of precipitation in response to the increased concentrations of acids is only marginal, which is ascribed to neutralization of acidity by ammonia and calcium carbonate.

One of the method used is purification with iodine, however people with thyroid issues and expecting ladies should not use this method due to the adverse health effects on this group of people. This method would remove bacteria in the water effectively but results in a taste in the water.

An alternative method is to boil the water, this process would kill most of the micro-organism that is harmful but requires time and does not remove chemical contaminants. A drawback of this method is the release of soot and carbon dioxide to the environment.

A filtering device can also be used. Filtration is chemical free and is more effective in removing microorganism not purified by boiling or iodine treatment. Compared to the two other methods, filtration is more expensive but reusable method and can be done in a relatively short time.

Compared to the methods used to purify municipal water supplies, the methods listed above are relatively simplified, for instance, water purified for municipal use go through rigorous processes which includes filtration, sterilisation, fluoridation etc. before it is released for public consumption.

2. Explain why desalination techniques, despite proven technological effectiveness, are not used more widely to produce potable drinking water. 

Desalination is not widely used as the method uses a lot of energy. Desalination plants around the world consume more than 200 million kilowatt-hours each day, with energy costs an estimated 55 percent of plants’ total operation and maintenance costs. It takes most reverse osmosis plants about three to 10 kilowatt-hours of energy to produce one cubic meter of freshwater from seawater.  Therefore, while desalination is an effective method to produce potable water, it is not widely used.

3. Water quality in a chemistry 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?

Solder found in the pipe joints or from lead pipe are likely the major source.

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 are unlikely to cause the elevated lead levels as most experiment would avoid using Lead (a toxic metal). Assuming that if any experiment involve the use of Lead, it is assumed that such toxic substance are not dumped into the drain, but handled with caution.

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

Only water-soluble vitamins would be expected to be polar molecules. Though a fat-soluble vitamin may contain polar bonds in portion of the molecule, the bulk of the molecule will be non-polar, this means the molecule will be non-polar since the dominant interaction is non-polar. Polar covalent bonds attract to water through hydrogen bonding and may allow the molecules to dissolve in water, while nonpolar covalent bonds favor interactions with the nonpolar chains in lipids.

• The emitted heat energy is mainly retained by the atmosphere thus the Earth does not cool rapidly even though the energy leaving Earth’s surface is almost twice of the energy that strike Earth’s surface.

2. Decide and explain where the stamen is correct or incorrect. Explain.

• The stamen is incorrect. The difference between weather and climate is the measure of time. Climate describe the average weather for a certain region in the long term of decades of year while weather describes the condition of the atmosphere over a short period of time. Having said that, particularly cold seasons like the winter will not mean that the Earth is getting cooler. Thus, using weather as a reference is not reliable. It would be more reliable to use climate for statistical data about the Earth’s temperature and warming/cooling trends.

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?

• Water in the atmosphere absorb the microwave radiation and this will interfere with the detection of the subject thus it was not successful.

4. 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 one and explain why)?

•  [Short Run] I believe that air quality will pose the most serious problem for us in the short run. This is because we live in Singapore, a bustling city where transportation and industries are booming. This causes a lot of emission and affects the air quality.

• [Long Run] The stratospheric ozone depletion will pose the most serious problem for us in the long run. It does not pose a direct and immediate effect because of the proximity of the ozone hole from Singapore. Over exposure to ultraviolet (UV) light can damage the skin or cause sunburn. In some cases, it leads to an increased risk of certain kind of skin cancer.

Question 1

A. A charcoal briquette burns

Exothermic. As it burns, heat is released.

B. Water evaporates from your skin

Endothermic. For evaporation to occur, water absorbs the necessary heat from the surroundings

C. Ice melts

Endothermic. Melting occurs when ice absorbs heat from the environment

Question 2

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

A: The bond energy of the product must be larger than the bond energy of the reactant to produce a very exothermic reaction. This is to form a very large net negative energy

Question 3

Q: How might you explain the difference between temperature and heat to a friend? Use some practical, everyday examples?

A: Let’s use hot water as an example. It would be preferable to have a single drop of water scald you as compared to an entire jug of water, even though the temperature remains constant. This is because temperature is just a measure of heat energy. A larger volume of hot water means that there is more heat and thus your burn will be more severe.

Question 4

A. The knocking characteristics of this gasoline?

An octane rating of 98 implies that the mixture contains 98% isooctane and 2% n-heptane. This means that it is more resistant to knocking than octane with lower rating.

B. Whether the fuel oxygenates

The octane rating does not reveal whether the fuel contains oxygenates. This information should be found around the pumps on labels.