1a) C5H9N3

1b)  NH2 from this histamine structure

1c) The nitrogen in Amine (NH2) makes it water-soluble

2a)  C16H21N3

2b) Because of the similar aromatic rings in both of these structures,  allowing anti-histamine to compete with histamine

3) Aspirin, morphine, amphetamine, estrogen falls under produce a physiological response in the body while penicillin and Keflex antibiotic under inhibit growth of substances that cause infections

4a) The herbal supplement manufacturers need to be honest in their product by putting labels to support their claim that the products are safe for consumption, explaining the functions of the ingredients listed, whether or not these ingredients may or not be suitable to certain groups of people that might get allergic reactions from it.

4b) In Singapore, under Herbal/alternative it says that it is not subject to approvals licensing or registration before sold locally, they need not be licensed by HSA, dealers are accountable for ensuring information is truthful. Under OTC medicines/ prescription, they are subject to checks and product registration before sold and must be licensed by HSA. The difference in regulations may be due to herbal medicines containing typically ingredients from natural source

Image reference:

 https://www.reddit.com/r/Drugs/comments/sn54c/i_thought_you_guys_would_like_this_wallpaper/

http://www.celestialroots.com/histamine.php

1. Foaming agent will transform molten polystyrene into Styrofoam to have a porous cellular structure. In acetone, Styrofoam will dissolve in it and due to its porous structure, it will allow large volume of acetone to be dissolved. Hence when acetone has evaporated, the foaming agent is removed giving polystyrene to return to its unaltered form, rigid and translucent. Therefore, Styrofoam will become denser and solid. Image below depicts the porous property of Styrofoam.

Image source: http://www.foardpanel.com/open-vs-closed-cell-foams/

2a.The reason why branched LDPE cannot be used due to the fact that molecularly it is branched. This means that there is alot of pores within the branched LDPE. This means that it is not resistant against physical force such as cutting forces etc.

2b. the molecular reason as to why the linear HDPE is successful in this application is due to the fact that it is linear and molecularly it means that more fibres can be fit into the material per unit area. this means that the fibres are tightly packed and have high resistance towards physical forces.

Image source: electronicpackaging.asmedigitalcollection.asme.org/data/journals/jepae4/930123/ep_136_03_031002_f002.png

3.

When the plastic bag (made of long-chain polymer molecules) is pulled, the randomly dispersed molecules align in the direction of the pull. Hence, the plastic becomes larger and thickness decreases, a phenomenon known as necking. The same thing does not happen to paper. Paper is not ductile – it does not deform elastically due to its atomic structure

4a) Hydrophilic, Easy to mould, Allows oxygen to pass through, Bio-Compatible

(b) Hard contacts is made up of polymethylmethacrylate (PMMA), soft contacts lens are made up of hydogels.

 Contacts are transparent, unreactive to chemicals on eye surface and tough.

(c) Hard contacts absorb oxygen while soft contacts don`t. Hard lenses have microscopically porous nature to transmit oxygen to cornea, hence are known to be ” gas permeable”. Hence,  soft contacts rely more on “oxygen-rich” tears to provide oxygen to the eyes compared to hard contacts.

Soft contacts are made up of hydrogel, hence, making it easier to absorb water to keep lens soft and supple, however, it makes eyes dry out easily. Hard lens won`t pull away the moisture, hence providing moisture to the eyes.

Image source: http://www.ag-eyecare.com/services/contact-lenses/

1. The connection between the coal fired plant and poor visibility is that due to the combustion of coal in these plants, particulate matter are produced as well as the sulfur oxides. sulfur oxide will react with water in the air to produce sulfuric acid. the sulfuric acid will then form tiny droplets that do not absorb sunlight but reflect it and result in poor visibility. This is more prominent in the summer whereby there is more sunlight which accelerate the photo chemical leading to the smog.

https://skittledip.files.wordpress.com/2012/09/img_5065.jpg

1B. The estimated pH of the rain in the area will be 4.5.

https://s-media-cache-ak0.pinimg.com/originals/cf/35/11/cf351112cbbffd315414c1357adf0093.jpg

2. If the clothes are not hung dry or if the dishwasher and washing machine are ran with small loads or if there is insufficient insulation for hot water heater, more electricity will be consumed. This will result in the usage of more coal burning plants to produce the electricity. This will result in the production of sulfur oxides which will lead to acid rain.

https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Coal_fired_power_plant_diagram.svg/1280px-Coal_fired_power_plant_diagram.svg.png

When we walk or cycle or take public transport, there are less cars on the road. This will lead to the lower production of nitrogen oxide which is implicated in acid rain production. Thus the usage of less vehicles will reduce the chances of acid rain. When we buy locally produced food and products. There is less transportation involve in the process. This also results in reduction of nitrogen oxides.

https://cdn.shutterstock.com/shutterstock/videos/15014551/thumb/9.jpg?i10c=img.resize(height:160)

3. Sulfuric acid H2SO4, Hydrochloric acid HCl, Nitric acid HNO3, Phosphoric acid H3PO4, Ethanoic acid CH3COOH

Sodium, lithium, calcium, ammonium and potassium hydroxide NaOH, LiOH, Ca2OH, NH4OH, KOH

for acid, it is sour and change blue litmus paper red. It has pH less then 7

for bases, it is bitter, slippery to feel and changes red litmus blue.

4. The issues that arise in Singapore is haze. The acid deposition is outside our borders. The various countries that are responsible for the issues are those that have large industrialized zones that produces nitrogen or sulfur oxide.

1. Water should be purified prior to consumption to prevent the spread of disease causing microorganism that is present in the water.There are several ways to do it while hiking. The first way to do it will be through the use of chlorine tablets. While it is very cost effective and effective in terms of water treatment, however, it tends to leave a bad aftertaste in the water. The second method that can be used is distillation. The water is heated up till boiling point whereby it will then evaporate and the water vapor will condense on the plastic sheet above it and can be collected as potable water. This method can be cheap and cost effective but it requires sufficient amount of heat to allow the water to evaporate. This methods are usually combined to treat water in municipal water supplies, and thus they are similar in terms of the idea used to treat the water
2. Desalination is not used large scale to produce potable water as it requires high amount of energies to remove the salts from the water. This leads to high cost as compared to other water treatment such as chemical treatment. Further more it requires large facilities to carry it out and it is also extremely time consuming and complicated.
3. The major source of the lead comes from the lead leaching out of the pipe. the research activities carried out in the chemistry building should not contribute to the elevated lead levels as chemical waste from the labs are not to be disposed into the sink as chemical waste should be separately handled with care and dignity deserving of a research institute.
4. I will expect the water soluble vitamins to be polar molecules as water is a polar molecule and it takes like to dissolve like and thus for water soluble vitamins to dissolve in water, it has to be polar. However for fat soluble vitamins, I will expect it to be non polar. This is because fats in the body is non polar and based on the above theory, fat soluble vitamin should be non polar.

1. The Earth is not cooling rapidly due to the heat energy being trapped by the greenhouse gases that are present in the atmosphere and the clouds such as carbon dioxide, methane and water vapor.
2. The statement is incorrect. This is a common misconception that global warming will only result in the increase in temperature on the earth surface. Global warming, is more scientifically known as the effect on temperature change due to the activities carried out by humans. The effects of global warming can be defined as any extreme weather conditions that can directly or indirectly result from human activities and this means that hot areas becomes hotter while cold areas becomes colder.
3. This is not functional because microwaves will be absorbed by water vapor present in the air and this will result in the loss of the microwaves and it will not function as a radar. The picture below shows that water absorption spectrum increases as the wavelength of the waves increases.
4.  We believe that in the short run the air quality is of a more serious concern this is because that bad air quality has a more direct impact on us in the short run while for the long run scenario, we believe the ozone depletion is of a more serious concern as the health implication of ozone depletion is more severe as compared to global warming. Furthermore, the effects of global warming is more easily adapted to by us that that of the ozone depletion. Lastly ozone depletion cannot be fixed easily due to the equilibrium nature of the ozone layer while the causes of global warming can be more easily rectified.

1b. Sweating is a process where heat is taken into the sweat and our body will feel cool. This reaction is endothermic since heat is taken in.

1c. When ice melts, it’s physical properties change from a solid state to a liquid state. This process requires heat to break the bond within the solid molecules therefore it is an endothermic reaction.

2. To yield a good explosion, a large amount of energy in the form of heat is released. The net energy difference between the products and reactants must be a large negative value(exothermic reaction). Thus, energy of the products is a negative small value while the reactants’ energy is a positive large value. From this, the relative bond strength of products is weak since the bond energy to break the bond is low while the reactants have strong bond as the bond energy is high.

3. Heat is a form of energy and it can be felt whereas temperature is a relative measurement. An example would be fever where the person’s body will feel warm and this relates to heat. Temperature is known when a thermometer (an instrument to measure temperature system) is used.

4a. This gasoline has an octane rating of 98 which refers to knocking characteristic of 98% isooctane and 2% heptane.

4b. Oxygenates are compounds added into fuel to reduce knocking and carbon monoxide emission. Each oxygenates compound has its own octane rating. Given the octane rating of gasoline just by itself does not tell whether the fuel comprises of oxygenates.

Can we really send ozone up?

Interesting perspectives from different groups

When will the ozone hole stop expanding???
At the end of humanity???

Makes me concern about the ozone hole and how we can play a part in stopping the hole from expanding.

However, ozone cannot be sent into the atmosphere as it would take a large amount of energy to send the ozone to the ozone layer. A large quantity of ozone will also need to be sent into the atmosphere which is not cost effective. In fact, it would cost less to stop destroying the ozone layer/screen.

Ozone molecule: