Month: February 2017

1. Ways to purify water while hiking:
   a. Heating the collected water and collecting the condensed waterBoiling helps to remove microorganisms by killing them however it cannot remove any chemical contamination of the water. Boiling cause environmental pollution as it can release carbon monoxide and soot to the environment.

   b. Purify water using iodine.
   Like boiling, iodine helps to remove microorganisms but cannot remove any chemical contamination. It takes a shorter time compared to boiling however tablets are more costly. Additionally, it is not advisable to take this in the long run as there are adverse health effects for pregnant women and people with thyroid conditions.

   c. Filtering water with a filtering device.

   Filtration can remove many microorganisms that cannot be removed by iodine or boiling. It also takes the fastest amount of time. However it is more costly thank heating or using iodine.

2. Desalination techniques such as reverse osmosis and distillation are expensive even though they are effective.
3. a) Sources include corrosion of lead pipes, solder drinking fountains and water tanks.b) It does not contribute to the elevated lead levels as the drinking and research waste pipes should be separated hence the by products do not go into the water source.
4. Water soluble vitamins are polar whereas fat soluble vitamins are non polar. To dissolve in water, the molecules have to be polar to favour hydrogen bonding with water molecules. Whereas, for fat soluble vitamins, they have to be non polar to form hydrophobic interactions with the fat molecules to dissolve in them.

1. The atmosphere retains the heat so it still trapped in our surroundings. Molecules such as CO2 and H2O trap heat in our atmosphere.
2. Global warming has to do with the temperature change not climate change. Having cooler seasons like winter does not mean that the region is getting cooler.  Climate describes the typical and average weather a region will have over a period of time. Most of the time, climate is used for statistics about earth’s temperature and whether it’s getting warmer or colder.
3. It heated up the air around the machine, causes diseases in the operators of the radar and the absorption of the microwave through water would interfere in detecting other objects.
4.  It will not be dependent on the geography. Most people are concerned about the air quality in the short run. The ozone depletion is too distant for people to be as concerned.

1a. The reaction is exothermic as heat is given off when the charcoal burns.

1b. The reaction is endothermic as water absorbs heat from the skin allowing it to evaporate and thus cooling the skin.

1c. The reaction is endothermic as ice absorbs the necessary heat which allows it to melt.

2. For a good explosion to occur, the bond energies of the products have to be larger than those of the reactants. This will lead to a negative energy change. The larger the energy change, the more exothermic the reaction will be.

3. Temperature indicates the direction of the heat flow whereas energy is a form of energy. Heat flows from an object at high temperature to one with lower temperature. An example would be a cup of hot water. Spilling a cup of hot water on yourself would hurt much more than spilling a drop of hot water on yourself even if both the cup and the drop of water are of the same temperature.

4a. The gasoline has the same characteristic as amixture made up of 98% of isooctane and 2% of n-heptane.  As a ‘premium’ gasoline, it has a higher octane rating than other blends sold at gasoline stations and is more resistant than these lower octane rating blends.

4b. Rating does not provide any information with regard to whether the fuel contains oxygenates.