Monthly Archives: February 2017

Research

CM8001: AE 5 Answers

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1. Tie a plastic ziplock bag on to a big leaf with direct sunlight. It is definitely cost effective but it may take a longer period of time. It is similar to distillation method as water vapour produced from the respiration of the leaf will condensed on the cooler surface of the plastic, and water droplets will form upon the loss of energy from the vapour molecule, resulting in the change in phase. This water droplet will then accumulate within the plastic ziplock bag as purified water. We can also use water purification tablets which are chlorine dioxide tablets to make potable water.

2. Cost is high to build the plant. Additionally, the cost is also relatively high to produce a small amount of water. Large amount of land is also needed so countries that cannot afford to provide such land space may not be able to use desalination technique to purify water. Desalination technique is also not suitable for landlocked countries.

3a. Corrosion of plumbing system from pipes and erosion of natural deposits.

3b. There could be a possibility of that happening but the chances are low as such chemical plants will have strict regulations to prevent such contamination to occur.

4. Fat soluble vitamins have few or no polar groups while water soluble vitamins have more polar groups than non polar groups which can form hydrogen bonds with  water molecules.

Research

CM8001: AE4 Answers

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  1. The energy that leaves the Earth’s surface as radiation is absorbed via the greenhouse gases present in the atmosphere. Thus, the energy is retained within the atmospheric layer instead of actually leaving the Earth as “loss of energy”.
  2. Global warming will make winters colder. The worsened global warming will increase the precipitation because the atmosphere can hold more moisture. There will be an increase in cold air and water vapour, and therefore, an increase in snow; the statement is incorrect.
  3. Our group’s assumption is that the absorption of microwave radiation by water in the atmosphere interferes with the detection of intended objects, or that it was necessary to shield the radar to protect people around it from harmful microwaves that could interact with the water in their bodies.
  4. Air quality is the most vital. Although all are important in the long run, we can feel the effects on our health immediately, like the scenario in Beijing at the moment. Global warming and ozone depletion take time to worsen.
Research

CM8001: AE 3 Answers

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1a. Charcoal briquette burning is an exothermic reaction. It produces heat, from personal experience.

1b. Endothermic reaction, as heat is absorbed for water molecules to gain energy and eventually gain sufficient energy to leave the water surface as a gas molecule, which is water vapour. Thats why we feel cool when we sweat.

1c. Endothermic reaction, it requires heat is absorbed for ice molecules to gain kinetic energy and eventually gain sufficient energy to become a water molecule.

2. The starting reactants have much more energy than the products. Exothermic reactions need only release energy to the surroundings by converting chemical potential energy into kinetic energy. Therefore, for a good explosive, the bonds of the reactant is much stronger that the product ones.

3. Heat is why you feel hot or cold, and temperature is just the measurement of the average kinetic energy of the molecules. The room feels warmer, due to the heat energy in the room – the temperature is 25 degrees celsius.

4a. The quality of the gasoline is higher, the higher the rating the lower the knocking. Less impurities inside. It has 98 percent of isooctane and 2 percent of heptane.

4b. higher rating means more oxygenates. so it has a relatively high percentage of oxygenates. Thus, more complete combustion, and less pollutants.