Tag Archives: chemistry

CM8001 – Application Exercise 8 (05/04/2017)

Q1

a)C5H9N3

c) Amine functional group will form hydrogen bomb. with water molecules to make it water soluble.

Q2)
a) C16H21N3
b) They have in common a substituted ethylamine moiety (-CH2-CH2-N-) as an integral part of their molecule

Q3) Drugs that give physiological response in the body
-aspirin
-esterogen
-morphine
-ampethamine

Drugs that inhibits the growth of substances that cause infection
-penicillin
-(keflex) antibiotic

Q4)
a) All drugs are regulated in the US by the FDA. Herbal/traditional/chinese medicines are treated like supplements than drugs. As such, they’re not placed under the same tight and strict regulations medicines and drugs have to go through. This is why such supplement/traditional medicines do not need to go through clinical trials.

b) Health supplements like those are not subjected to approvals prior to import and sale in Singapore.

Meeting’s Log 11

Location: SouthSpine Benches
Time: 2.30pm – 3.30pm

Team members who attended:
Andrew, ChungKei, Elyza, Jerome and Michael.

Team members who did not attend: N/A

Topics discussed:
1. AE8

Tasks to be done before the next meeting:
Qns 1 – Andrew
Qns 2 – ChungKei
Qns 3 – Michael
Qns 4 – Jerome and Elyza

Problems: N/A

Plan of action:
Post answers online.

CM8001 – Application Exercise 7 (23/03/2017)

1) Styrofoam is almost 95% air (the foaming agent), and when dissolved in a solvent such as acetone, the reaction releases all the air that has been compressed in the styrofoam. What remains is only the styrene which makes it more solid and denser compared to its original form.

2a) Branched LDPE does not have a crystalline structure. It has a weaker intermolecular forces of attraction so the material is not as strong. Hence, it cannot have high resistance to being cut like HDPE.
2b) HDPE is linear giving a crystalline structure so that the attraction between molecules is stronger and has the necessary strength. At the same time, by using a thin layer as liners can reduce the rigidity so that it is more flexible yet the strength can be maintained which is important for surgical gloves.

3) When the piece of plastic is stretched, the strip narrows and neck down. The molecules become align parallel to each other and in the direction of the pull. This alteration of the three dimensional structure is not reversible, and if pulling continues, the plastic breaks.

When the same pulling force is applied to a piece of paper, the paper tear rather than stretching. The cellulose molecules in paper are hold far more rigid in place and are not free to aligned.

4a) They must not react with our bodily fluids, must be non-toxic to our bodies, have to be stable over time for the intended use and they would have to be easily implanted.
They would have to be non-toxic to the human body.

4b) Contact lenses are made up of either acrylamide, fluorosilicone acrylate or methyl methacrylate. Contact lenses that are made up of acrylamide are called soft lenses whilst contacts made from fluorosilicone acrylate or methyl methacrylate are called Rigid Gas Permeable (RGP) or Gas Permeable (GP) lenses. Soft lenses are desirable as the polyacrylamide lattice is polar hence highly hydrophilic. This is beneficial to those who frequently suffer with dry eyes that would make wearing contact lenses very uncomfortable. Flurosilicone acrylate was chosen as it has a high oxygen permeability and methyl methacrylate was chosen due to its ability to enhance optical quality and stability.

4c) The main difference is that soft contact lenses are made of silicone as compared to hard contact lenses which are made of PMMA, a non-gas permeable plastic. What this means is that the new property of the soft contact lenses allow oxygen to reach the human eye as compared to the hard contact lenses. the result is that soft contact lenses feel more comfortable for the human eye.

Meeting’s Log 9

Location: Tables outside LT 23
Time: 1.30pm – 2.30pm

Team members who attended:
Andrew, ChungKei, Elyza, Jerome and Michael.

Team members who did not attend: N/A

Topics discussed:
1. AE7

Tasks to be done before the next meeting:
Qns 1 – Jerome
Qns 2 – ChungKei
Qns 3 – Elyza
Qns 4 – Andrew and Michael
Think of idea for 2nd video.

Problems: N/A

Plan of action:
Post AE7 answers online.

Meeting’s Log 8

Location: Hive
Time: 3pm – 5pm

Team members who attended:
Andrew, ChungKei, Elyza, Jerome and Michael.

Team members who did not attend: N/A

Topics discussed:
1. Video 1 – Chemical Concepts

Tasks to be done before the next meeting:
– Finish editing the video and upload it to YouTube
– Think of new idea for 2nd Video.

Problems: N/A

Plan of action:
N/A

Meeting’s Log 7

Location: Tables outside LT 23
Time: 12.30pm – 1.30pm

Team members who attended:
Andrew, ChungKei, Elyza, Jerome and Michael.

Team members who did not attend: N/A

Topics discussed:
1. Review feedback on the blog from Prof Felipe
2. Video plans

Tasks to be done before the next meeting:
– Add Captions
– Extend Page on “Impact on Society”.

Problems: N/A

Plan of action:
Begin filming on Wednesday.

CM8001 – Application Exercise 6 (15/03/2017)

1a) Burning coal produces some amount of SO2, which reacts with oxygen and water in the air to form sulfuric acid. Molecules of sulfuric acid in the air form tiny droplets (aerosols) that reflects sunlight, thus reducing visibility (much like haze).

1b) Since pH is a logarithmic scale, 10 times increase in acidity translates to 1 point decrease in pH. pH of rainwater is around 5.3 naturally, hence the pH of rainwater in the park is estimated to be around 4.3.

2a) Electricity is needed to run electric dryer and burning of coals will be required to generate electricity. This process emits gases like sulfur dioxide. Sulfur dioxide going into the atmosphere will react with water to form acid rain. Hang clothes to dry will not need electricity.

2b) Large amount of NOx is emitted from vehicles, hence, contributing to acid rain when it reacts with water. By taking public transport, walking and bike will reduce the amount of NOx emission.
2c) Electricity is needed to run the dishwashers and washing machines. By accumulating more dishes, it reduces the usage of the machines, hence, less electricity is used which in term reduces the amount of sulfur dioxide produced from coal-fired electric power plant.

2d) Heating up the water requires burning of fossil fuels. By adding additional insulation, it reduces the amount of heat loss, keeping the temperature slightly higher compared to uninsulated pipes. Hence, less energy is required to heat up the water since temperature can be maintained. Less sulfur dioxide produces from power plants will reduce acid rain.

2e) By buying home grown food, this reduces the need to import food from other countries. This reduces the distance for the food to be transported especially if it is from other countries. Hence, less pollutants like CO2, SO2 and NOx will be produced during transportation and they are sources for formation of acid rain.

3a) Give the names and chemical formulas for five acids and bases

Hydrochloric Acid, HCl
Sulfuric Acid, H2SO4
Ethanoic Acid, CH3COOH
Phosphoric Acid, H3PO4
Fluoroantimonic Acid, HSbF6

Sodium Hydroxide, NaOH
Ammoniun Hydroxide, NH4OH
Barium Hydroxide, Ba(OH)2
Aluminium Hydroxide, Al(OH)3
Iron II Hydroxide, Fe2(OH)2

3b) Name three observable properties generally associated with acids and bases
Acids generally have a sour taste whereas bases generally taste bitter.
When red litmus paper is dipped into a base it turns red and when a blue litmus paper is dipped into an acid it turns blue
Bases have a soapy feel to it whilst strong acids can burn our hands due to their corrosiveness.

4) The acid depositions can be originated from inside and outside singapore’s borders, but mainly inside.

Singapore does actually experience acid rain to a certain extent. The lower pH record in some location suggest that acidic ions released are contributed by SOx and NOx from coal-burning from heavy industries, in places like Jurong Island and western part.

The acid deposition is also came from ship that used fuel with a much lower sulfur content and emits a lot of SOx.

While outside Singapore’s border, action from our neighbors such as indonesia whose forest caught fire will lead to contributing acid deposition. Other than that, other asian nation which also grow into industrialization can also contribute to large number of SOx emission.

Hence, the acid deposition here originates from both inside and outside Singapore’s borders.