1b)

1c)

2a) C16H21N3
b) The ethylamine moiety of the antihistamine is able to interact with the histamine receptor competitively and block the site of histamine binding.

3) Drugs that produces a psychological response : Aspirin, Morphine, Estrogen, Amphetamine

   Drugs that inhibit growth of substance that cause infection :(Keflex) antibiotics, Penicillin

4a) The herbal supplement manufacturers should be details of the supplement on the packaging.

b) The legislation available in Singapore is the HSA Medicine Act and guidelines for traditional materials that regulates herbal medicine. In 1995, a traditional medicine unit was set up in the MOH. Under TCM Practitioners Act, in 2002, act 34 was passed to allow government to approve or reject applications for TCM clinic’s registration.

Gasoline is a fuel that is distilled from the crude oil. Gasoline consists of organic compounds which exists in the form of various structures and include linear and even cyclic structures such as aromatic or alkane cyclic hydrocarbons. While the composition of gasoline may vary, a common gasoline structure is provided below. In the diagram provided, gasoline is depicted to have 8 carbon atoms and 8 hydrogen atoms.The density of gasoline ranges from 0.71 to 0.77kg/m3.

Gasoline plays an important role in our world today. In the United States of America alone, there is a consumption of 140.43 billion gallons of gasoline in the year of 2015.  Gasoline is mainly used to fuel internal combustion for engines of cars, motorcycles, light trucks, boats and other transport vehicle. 28% of the total energy consumption in the United States of America is due to the transportation. Out of that 28% of total energy consumption for transportation, gasoline contributes up to 56%, making gasoline the most commonly used transportation fuel in the U.S.A.

This blog covers the chemistry concept of gasoline which includes a brief introduction of gasoline and concepts of gasoline in great details. The concepts which will be covered is as shown below:

1) The combustion of gasoline

2) Production of gasoline

3) Ignition of car engine and preignition

4) Knocking and octane rating

5) Ways to improve octane rating

We will also be discussing the implications of gasoline on our environment.

Chemical Concept of Gasoline

In this section, we will be discussing 5 chemical concepts of gasoline.

Concept 1: Combustion of Gasoline

Gasoline is not a simple hydrocarbon when compared to less complexed hydrocarbons such as methane with four hydrogen atoms and one carbon atom. This may cause complications due to incomplete combustion of gasoline. Under complete combustion of a simple hydrocarbon with oxygen, the hydrogen atoms combine with oxygen to form water (H2O) while the carbon atoms form carbon dioxide (CO2) with oxygen. The equation for a complete combustion of gasoline is provided below.

Under incomplete combustion, for example, when a limited supply of oxygen is present, carbon monoxide (CO)  and carbon (C) may be produced instead. A general equation for incomplete combustion of a hydrocarbon is provided below:

hydrocarbon + oxygen    →    carbon monoxide + carbon + water

The production of gasoline involves a process known as fractional distillation and this phenomena is dependent on the differing boiling points of different hydrocarbons. This process is further discussed in the paragraph below.

Concept 2: Production of gasoline:

The production of gasoline begins with the fractional distillation of crude oil. The process of fractional distillation separates the crude oil into different components based on the different boiling points of each component. Hydrocarbons with longer carbon chains will have higher boiling points and hence, will remain at the bottom of the distillation column as compared to hydrocarbons with shorter carbon chains. Gasoline has an average of 4-12 Carbon atoms have a relatively low boiling point of 40 – 200 degrees celsius as compared to other components of crude oil. Hence, upon heating the crude oil such that it reaches the boiling point of gasoline, gasoline changes into gaseous form. When this gasoline in gaseous form cools below its boiling point, it condenses into liquids and subsequently, drawn off the distilling column. This process of fractional distillation of crude oil to obtain gasoline can be illustrated using the picture above.

Concept 3: Ignition of Car Engine and Preignition

In order to ignite the car engine, gasoline vapour and air are first drawn into a cylinder. As the both components are drawn into the cylinder, they will be compressed by a piston. The compression will eventually lead to the ignition by spark. Normal combustion occurs as the fuel-air mixture is ignited by the spark plug. The flame produced will travel across the combustion chamber immediately and smoothly until the fuel is used up.

Nevertheless, premature firing known as pre-ignition might also take place as the car engine is ignited. Pre-ignition takes place as compression leads to fuel ignition before the spark occurs. Due to preignition, this condition will lead to lower energy efficiency and higher fuel consumption. The reason pre-ignition happens is the piston is not in its optimal location as the combusted gas expands.

Concept 4: Knocking and Octane Rating

Knocking takes place as violent and unregulated pressure that are several times larger than usual pressure builds up in the engines. Knocking normally takes place after the fuel is ignited by the spark, causing the uncombusted mixture of fuel and air to combust at supersonic speed with an abnormal rise in pressure.As the result, knocking generates an irritating metallic sound. Besides, knocking also results in the loss of power, overheating and eventually leads to engine damage as knocking becomes more serious.

In the last century, the chemical composition was identified to be one of the factors leading to knocking.As the consequence, octane rating was applied to designate the gasoline’s resistance against knocking. Isooctane is assigned an octane rating of 100 as smooth ignition of engine takes place as isooctane is used as the fuel. On the other hand, heptane is assigned an octane rating of 0 as severe knocking of engine occurs when heptane is used as the fuel.

Each particular kind of gasoline is assigned to an octane number which is positive in value. For certain type of gasoline, the octane rating might exceed 100! For an instance, if the gasoline has an octane rating of 95, this illustrates that the gasoline possesses the same knocking characteristics as a mixture of 95% isooctane and 5% heptane.

Concept 5: Ways to increase Octane Rating

Octane rating is defined as a fuel’s ability to resist ‘knock’ and hence a the higher the octane rating, the greater the fuel is in resisting ‘knock’. As knocking reduces energy efficiency and causes serious damage to the vehicle engine, hence there is vigorous research to improve octane rating. Hitherto, there are a few methods implemented or used to be applicable in order to improve the octane rating:

1. “Re-form” of Hydrocarbon

Comparing a linear hydrocarbon and a more branched hydrocarbon, the latter has a more compact structure. As the result, this compact structure imparts a more controllable combustion.” Re-forming” of hydrocarbon from a linear hydrocarbon to a more compact structure can be done by passing the linear hydrocarbon over rare and expensive metal catalyst, such as platinum, palladium and rhodium.

2.    Addition of Anti-knocking Agent

In the previous century, teraethyllead (TEL)  used to be added into the gasoline as the anti-knocking agent. Anti-knocking agent helps to reduce knocking besides acting as a lubricant on the pistons. However, through a research done in the late 1970s, it was found out that lead emission from the car exhaust fumes had adverse effects on the IQ of the children living in the cities. The presence of lead also indicates that catalytic converter cannot be used to cut down noxious emission. Following the findings,  most of the developed countries have come to a decision to ban TEL due to the harm caused by TEL.

3. Addition of more aromatics into the gasoline pool

Due to the addition of more aromatics into the gasoline pool, this as the result, increase the crude oil requirement for every litre of fuel. In addition, aromatics are generally carcinogenic and toxic. The addition of more aromatics into the gasoline also implies that the public’s exposure towards toxic aromatics are also increased. However, as the quantity of aromatics added is minute, hence, this measure is not viewed as a significant problem. This method is implemented in the Europe countries.

4. Use of Oxygenated Gasoline

Fuels with oxygen-containing additives are known as oxygenated gasoline The examples of oxygen-containing additives includes ethanol and methyl tertiary-butyl ether (MTBE). As these additives contain oxygen, the oxygenated gasolines combust more completely, thus producing less carbon monoxide as compared to their non-oxygenated counterparts. The details related to the oxygen-containing additives are shown below:

1. Ethanol

The addition of ethanol to the gasoline pool is a common practice in countries such as Brazil.

1. b)  MTBE

Among all measures mentioned to increase octane number, the gasoline added with MTBE has the highest octane rating. Addition of MTBE in the gasoline pool is done commonly in the USA. However, concerns have been raised recently about the addition of MTBE into the gasoline pool as MTBE appears to be leaking into the drinking water in parts of the USA, notably California. The use of MTBE as the fuel additive is being phased out in certain states.

Implications to Society

Due to widespread uses of gasoline in our transportation network, it has caused many implications to our society such as: Environmental Impacts, Toxicity, Flammability

Environmental Impact

According to US Energy Information Administration, a gallon of gasoline combusts to produce 8.74 kilograms of carbon dioxide. Given that  26 percent of 2014 greenhouse gas emissions in the US comes from transportation, and 90% of the fuel is petroleum based including gasoline and diesel, combustion of gasoline is a major source of anthropogenic carbon dioxide, which exacerbates climate change.   

Combustion of gasoline in engines also requires high temperature and pressure, resulting in the production of nitrogen oxides, contributing to the production of photochemical smog. The use of leaded petroleum in the past has also resulted in the decrease in efficacy of the catalytic converter, resulting in a greater production of nitrous oxides. During 1962, the “Great Smog” that enveloped London resulted in 4000 more people dying in that week as compared to that period of time during the previous year.

Toxicity

Use of leaded gasoline has resulted in an increase in ambient lead concentration, resulting in higher lead concentration in the blood through inhalation, ingestion of contaminated dust, water and food. Lead accumulated in the body have profound effects on children, affecting development of brain and nervous system. Adults are not spared the harmful effects of lead either, resulting in heightened risk of high blood pressure and kidney damage.

Even with the phasing out of leaded gasoline, unleaded gasoline also contains hazardous chemicals which are present in different compositions. National Institute for Occupational Safety and Health has classified gasoline as a carcinogen. Gasoline contains benzene, xylene, toluene and its additives are ethanol, methanol and methyl tertiary butyl ether. These chemicals are moderately to mildly toxic at acute doses. These toxins are not normally absorbed into our body system, but due to the volatility of the chemicals we can be exposed through breathing in the toxins, or ingesting them.

Flammability

Gasoline, like other hydrocarbons, are flammable and when mixed in air, can rapidly combust and burn. Hence any leakage of gasoline, due to its volatile nature, is a fire hazard which has to be handled with particular care when transporting and storing the liquid. Hence petrol stations often have their gasoline pump equipped with anti-spillage nozzles to prevent spillage, and erect signs to warn people not to expose any naked flame in the station.

Citations:

Innes, J. L. (2000). Biomass Burning and Climate: An Introduction. Advances in Global Change Research Biomass Burning and Its Inter-Relationships with the Climate System, 1-13. doi:10.1007/0-306-47959-1_1

BBC – GCSE Bitesize: Combustion. (n.d.). Retrieved March 22, 2017, from http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/carbon_chemistry/carbon_fuelsrev2.shtml

U.S. Energy Information Administration – EIA – Independent Statistics and Analysis. (n.d.). Retrieved March 22, 2017, from https://www.eia.gov/tools/faqs/faq.php?id=307&t=11

Kahn Ribeiro, S., S. Kobayashi, M. Beuthe, J. Gasca, D. Greene, D. S. Lee, Y. Muromachi, P. J. Newton, S. Plotkin, D. Sperling, R. Wit, P. J. Zhou (2007). Transport and its infrastructure. In Climate Change 2007: Mitigation.

Colbeck, I & Mackenzie, AR 1994, Air pollution by photochemical oxidants, Air Quality Monographs Vol 1, Elsevier, Netherlands.

Tracton, S. (2012, December 20). The killer London smog event of December, 1952. Retrieved March 22, 2017, from https://www.washingtonpost.com/blogs/capital-weather-gang/post/the-killer-london-smog-event-of-december-1952-a-reminder-of-deadly-smog-events-in-us/2012/12/19/452c66bc-498e-11e2-b6f0-e851e741d196_blog.html?utm_term=.c375c69463df

Lead poisoning and health. (n.d.). Retrieved March 22, 2017, from http://www.who.int/mediacentre/factsheets/fs379/en/

Reese, E., & Kimbrough, R. D. (1993). Acute toxicity of gasoline and some additives. Environmental Health Perspectives, 101(Suppl 6), 115-131. doi:10.1289/ehp.93101s6115

Gasoline. (n.d.). Retrieved March 22, 2017, from http://www.chemistryexplained.com/Fe-Ge/Gasoline.html

Refining Oil. (n.d.). Retrieved March 22, 2017, from http://chemistry.elmhurst.edu/vchembook/513refining.html

Brain, M. (2002, February 06). How Gasoline Works. Retrieved March 22, 2017, from http://science.howstuffworks.com/gasoline1.htm

U.S. Energy Information Administration – EIA – Independent Statistics and Analysis. (n.d.). Retrieved March 22, 2017, from https://www.eia.gov/tools/faqs/faq.cfm?id=23&t=10

Energy Use for Transportation. (n.d.). Retrieved March 22, 2017, from https://www.eia.gov/energyexplained/?page=us_energy_transportation

Gasoline – Energy Explained, Your Guide To Understanding Energy – Energy Information Administration. (n.d.). Retrieved March 22, 2017, from https://www.eia.gov/energyexplained/index.cfm?page=gasoline_home

FirmGreen Fuels Facts. (n.d.). Retrieved March 22, 2017, from http://www.firmgreen.com/fuel/fuel_facts.htm

Lancaster, M. (2002). GREEN CHEMISTRY: An Introductory text. Cambridge, UK: The Royal Society of Chemistry.

Middlecamp, C., Mury, M., Anderson, K., Bentley, A., Cann, M., Ellis, J., & Roberts, K. P. ( 2015). Chemistry in Context: Applying Chemistry to Society (8th Edition ed.). New york: McGraw-Hill Education.

Meeting’s Log:

1st Meeting

Date: 8th March 2017 (Wednesday)

Time: 1430-1600

Duration : 1 hour 30 minutes

Location: Level B1, the Hive, Nanyang Technological University

Participants: Ng Pei Rou, Ang Shihe, Marie Hong Hui Min, Ernest Lim Jun Wei, Maharah Binte Abdul Mahid

Topic Discussed:

• Job allocation of the blog post is discussed.

• The chapter that is assigned is Chapter 4- Energy From Combustion. From this chapter, the topic that is selected is The Chemistry of Gasoline.

Actions To Be Taken:

• Ernest Lim will be in charge of the introduction.

• Marie, Pei Rou and Maharah will be in charge of the chemical concepts.

• Shihe will be in charge of the implication

• For the next meeting,  refinement and synergy of content will be done online via Skype and Google Docs.

• Next meeting: 18th March 2017 (Saturday), at 2115-2315

2nd meeting

Date: 18th March 2017 (Saturday)

Time: 2115 – 2315

Duration: 2 hours

Location: Skype

Participants: Ng Pei Rou, Ang Shihe, Marie Hong Hui Min, Ernest Lim Jun Wei, Maharah Binte Abdul Mahid

Topics discussed:

• Refinement and synergy of blog post content.

• Reviewing of the blog post is done by commenting in the Google Docs.

Actions to be taken:

• Second review of the blog post will be done on 22nd March 2017 (Wednesday), after the CM8001 lecture.

Review of The Actions Taken During last Minute:

• All the allocated tasks are completed.

3rd meeting

Date: 22nd March 2017 (Wednesday)

Time: 1500 – 1630

Duration: 3 hours

Location: Lecture Theatre 23, Nanyang Technological University

Participants: Ng Pei Rou, Ang Shihe, Marie Hong Hui Min, Ernest Lim Jun Wei, Maharah Binte Abdul Mahid

Topics discussed:

• Review for the second time of the blog post on Google Docs.

• Job allocation for two video assignments is discussed.

Actions to be taken:

• Video 1, which explains the chemical concepts is allocated to Pei Rou, Marie and  Maharah.

• Video 2, which explain the impact, is allocated to Ernest and Shihe.

4th meeting

Date: 29th March 2017 (Wednesday)

Time: 1330 – 1730

Duration: 4 hours

Location: Outside LT20

Participants: Ng Pei Rou, Ang Shi He, Marie Hong Hui Min, Ernest Lim Jun Wei, Maharah Binte Abdul Mahid

Topics discussed:

• Review of both video contents.

• Recording and editing of both videos.

• Submission of blog post and two videos.

Review of The Actions Taken During Last Minute:

• All the allocated tasks are completed.

2a. Low density polyethylene(LDPE) is made from ethylene and has an increased amount in branched bonds when compared to HDPE. The Branched arrangement of LDPE results in weak intermolecular bonds within LDPE and results in lower tensile strength, that is, the resistance against forces that pulls apart a material. Hence it does not provide the required density and strength for surgical gloves that will allow the Spectra liner to be highly resistant to being cut or torn.

2b. Linear arrangement of HDPE provides the required density and strength so that the Spectra liner will be highly resistant to being cut. However, to give its required flexibility, the use of a thinner layer of the HDPE will provide the characteristic.

3.When the piece of plastic is stretched, the strip narrows and “necks down”. The molecules become aligned and parallel to each other and follows the direction of the pulling force. The change in the structure is irreversible, and if the pulling persists, the plastic breaks. As the same pulling force is applied to a piece of paper, the paper tears rather than stretching. The cellulose molecules in paper are held more rigidly in place, and it is not possible to become aligned and be parallel to each other.

4a. The four properties of polymers are, non-toxic, stable over time of intended use, lack of reactivity in body fluids, and ease of implementation.

b. Rigid gas permeable lenses are made up of Polymethyl methacrylate (PMMA) while soft contact lenses are made up of Polymacon and polymer of 2-hydroxyethyl methacrylate (HEMA). The desirable properties of these materials are, non-toxic, permeable to oxygen, comfortable to wear, inexpensive. It can also be easily washed and due to its flexible property, it allows contact lenses to fit into the shape of a person’s eye easily.

c. Hard contact lenses are made up of PMMA while soft contact lenses are made up of silicone. The difference of material used allows soft contact lenses to be more comfortable to wear since it has a better fit to the eye and allows oxygen to reach the eye.

b) The average pH of rain should be neutral at pH = 7. Therefore, since the average rainfall in Mammoth Cave National Park is 10 times more acidic than natural, the difference in pH will thus be equals to 1. (log(10)). Hence, the estimated pH of rainfall in the park would be 7-1=6.

2a)Hanging laundry to dry instead of using a dryer reduces electricity consumption.By reducing the demand for electricity consumption, electricity production may eventually be reduced as well. As electricity mainly originates from coal burning which produces sulfur dioxide, a contributor to acid rain, the consequent reduction in sulfur dioxide production may thus reduce the production of acid rain.

2b)Walking, cycling or taking public transport instead of driving a personal vehicle will reduce the amount of cars on the road. This will reduce the amount of NOx gas produced from engines in the car. The NOx gas produced contributes to acid rain and reducing the gas will hence reduce acid rain.

2c) Running dishwasher and washing machine with a larger load means that there is a lower frequency of using the dishwasger and washing machine. This will reduce the energy usage in general and reduce the amount of fuel burnt to provide the energy. Therefore lower amount of SOx gas produced in the process and reduces acid rain.

2d) Adding additional insulation on hot water heater and pipes helps to reduce heat loss to the surround and thus lesser energy is required to heat the system up. Lower energy consumption will lead to lower coal burning and lower SOx gas formed.

2e) Buying local product means that there is a lower demand for overseas goods. This means that there is a lower need for airplanes and ships to deliver products across countries. This reduces the amount of NOx gas produced from the engines of airplanes and ship which will contributes to acid rain.

3a)

3b) Acids react with metals to liberate hydrogen. Acids conduct electricity. Acids changes blue litmus paper red. Base conducts electricity. Base changes red litmus paper blue. Base reacts with acid to neutralise their properties, forming water as a product.

4)In general, there is a drop in air quality in Singapore due to various factors such as industrial activities. Recently, Singapore’s air quality standards have fallen below WHO guidelines for three city-related pollutants, which includes pollutants such as sulphur dioxide, ozone and PM10.

One of the issues related to the acid rain in Singapore is the possible wipeout of native species in Singapore. Due to acid rain, the streams in nature reserve become more acidic, thus making the streams become less habitable for aquatic species.

The other issues raised related to acid rain in Singapore is the damage of buildings and statues due to acid rain. Damage is done on the buildings and statues via chemical reactions such as corrosion and rusting. As the result, this will increase the cost of operation for maintenance purpose.

Based on the information provided by NEA, the pollutants which cause acid rain (eg. sulphur dioxide) are released mainly from industries and motor vehicles. Among all industries, the refinery industry contributes the most to sulphur dioxide emission (93.1%). In conclusion, the acid deposition originates mainly from Singapore itself.

2) Firstly, desalination techniques are energy intensive. Distillation requires a huge amount of heat energy to evaporate the seawater.As for reverse osmosis, this technique requires high pressure to be applied to the seawater through a semi-permeable membrane. These translates to large amount of investment in both energy usage and infrastructure required.

Secondly, desalination techniques also result in environmental concerns. This problem arises due to the problem of disposal of residue. Highly concentrated brine, which is a form of inorganic salt can result in environmental degradation, especially aquatic ecosystems if dilution of brine is not done properly before disposal.

Besides, in economic terms, desalination techniques also require high cost. Since there are other cheaper options available currently, for an instance, water catchment and groundwater source, the cheaper options are highly preferred over the costly desalination methods to reduce the overall production cost of potable water. Moreover, investment into the energy source to carry out desalination and the advanced equipment and to desalinate water require high expenses too.

3) a)Possible sources of lead can be due to contamination by lead fuel, batteries or hazardous waste sties that seeps into the underground water storage. The major source in this case is most likely water contaminated by rusting and corrosion of piping made of lead, resulting in lead dissolving into the drinking water.

b)It is unlikely for the research activity to affect the lead levels as the waste products should have been properly disposed in the lab. Even if the waste is not properly disposed, the water supply to the drinking fountains should be supplied by PUB and not directly pumped from the underground water storage in the location.

4)We expect only water-soluble vitamins to be polar compounds. Water is a polar compound and according to the ‘like dissolves like’ rule, polar compounds will be able to solubilize other polar compounds. Thus polar compounds are hydrophilic and are “Water-loving”. On the other hand, vitamins that are fat-soluble, are hydrophobic, also known as ‘water-hating’ compounds. This is due to their non-polar nature. As mentioned above, according to the ‘like dissolves like’ rule, fat being a non-polar compound will only be able to solubilize other non-polar compounds. Thus fat-soluble vitamins must be non-polar in order to be able to solubilize in fat. being non-polar, they will not be able to solubilize in water due to the opposing polarities.

1b. Endothermic. When water molecules evaporate to form water vapour, water vapour contains more energy. Furthermore, the skin feels cool as temperature decreases when water evaporates, hence it is endothermic.

1c. Endothermic. Heat is absorbed when ice melts, forming water molecules in liquid state which contains higher energy.

2. For a good explosion, a large amount of energy should be released. Hence the reaction should be very exothermic. Therefore the energy taken to break the bonds from the reactants should be much smaller than the energy released to form the bonds from the products, hence there will be a large net energy released. Thus, bond strength in the reactants should be low and the bond strength from the products should be strong.

3. Heat is the energy that flows from the hotter object to the cooler object. Temperature determines the flow of the energy as a hotter object will have a higher temperature and vice versa. In winter when your hands are cold, heat flows from the heat pack to your cold hands, this is because the temperature of the heat pack is higher than the temperature of your cold hands.

4a. An octane rating of 98 has a knocking characteristics of 98% isooctane and 2% heptane.

4b. No oxygenates are not present as if they are, the octane rating will be equal or higher than 109.

1. Different energy and wavelength of electromagnetic radiation
2. Ozone layer
3. Chlorofluorocarbons (CFCs) and how it damages the ozone layer in stratosphere
4. Chemical bonds, subatomic particles and isotopes
5. Structural formula of a chemical

Today’s lesson is about the use of ozone and how its is currently being depleted. In today’s discussion, we discussed about the why it is not feasible for us to create ozone and then ship it up into the stratosphere to curb with the problem of ozone depletion. There are several reasons why this is not feasible. The 1st reason is that this way doesn’t solve the root of the problem. The method is also not feasible because there is too much ozone to be form and to be ship up into the stratosphere.