Session 6
Mammoth Cave National Park in Kentucky is in close proximity to the coal-fired electricity utility plants in Ohio Valley. Noting this, the National Parks Conversation Association (NPCA) reported that this national park had the poorest visibility of any in the country.
a) What is the connection between coal-fired plants and poor visibility?
Coal plants release huge amounts of water vapour along with the combustion process. Water-vapour when cooled becomes visible as fog. Hence, the connection is higher in areas that have cooler night time temperatures, leading to more fog produced.
b) The NPCA reported “the average rainfall in Mammoth Cave National Park is 10 times more acidic than natural. ” From this information and that is in your text, estimate the pH of rainfall in the park.
Average natural rainfall should be pH7. Since the rainfall in the park is 10 times more acidic, then pH should be 6.
2) Here are some examples of what an individual might do to reduce acid rain. For each, explain the connection to producing acid rain.
a) Hang your laundry to dry it.
It reduces the use of electric dryer and cuts down need for power companies. Hence, reducing the emission of SOx and NOx.
b) Walk, bike, or take public transportation to work.
It reduce the use of gasoline, cutting down the energy and gas such as NOx.
c) Avoid running dishwashers and washing machine with small loads.
Larger loads are more efficient in terms of energy consumption.
d) Add additional insulation on hot water heaters and pipes.
Decreases heat loss from water, thus requiring less energy to heat the water.
e) Buy locally grown produce and locally produced food.
They have low cost of transportation and it reduces the fuel burnt.
3)
a) Give names and chemical formulas for five acids and five bases.
b) Name the three observable properties generally associated with acids and bases.
a) Five acids
Hydrochloric Acid, HCl
Sulfuric Acid, H2SO4
Sulfurous Acid, H2SO3
Nitric Acid, HNO3
Phosphorus Acid, H3PO4
Five bases
Sodium Hydroxide, NaOH
Potassium Hydroxide, KOH
Calcium Hydroxide, CaOH
Ammonia, NH3
Magnesium Hydroxide, MgOH
b) Acid properties
– Turns blue litmus paper red
– pH indicator 1-6.9
– Phenolpthalein – colourless
Base properties
– Turns red litmus paper blur
– pH indicator 7.1-14
-Phenolpthalein – pink
4) The concerns of acid rain vary across the globe. Many countries in North America and Europe have websites dealing with acid rain. Either search to locate one (“Canada, acid rain” ) or use these websites in Canada, the UK, or Europe. What are the issues in the country you selected? Does the acid deposition originate outside the borders of the country?
Acid deposition is a problem in eastern Canada their waters sucha s streams, river and lakes and soil in this region lack natural alkalinity such as a lime base. Hence it cannot neutralise acid naturally. Some provinces are hardest hit because their water and soil systems cannot fight the damaging consequences of high levels of acid deposition. More than half of Canada consists of susceptible hard rock (i.e., granite) areas that cannot neutralize the effects of acid deposition. Hence, acid deposition do originate outside the borders of the country.
Reference: http://ec.gc.ca/Air/default.asp?lang=En&n=AA1521C2-1
Session 3
1) Understanding Earth’s energy balance is essential to understanding the issue of global warming. For example, the solar energy striking Earth’s surface averages 168 watts per square meter (W/m2), but the energy leaving Earth’s surface averages 390 W/m2. Why isn’t Earth cooling rapidly?
Answer:
Although the solar energy leaving the Earth’s surface is about twice the amount of energy striking the Earth’s surface, the Earth isn’t cooling rapidly as the greenhouse gases re-emit and absorb the heat in all directions which spread downwards and ultimately comes back into contact with the Earth’s surface. Hence, the energy radiated by the surface is preserved in the atmosphere.
2) Do you think the statement made by the cartoon is justified? Explain.
Answer:
The given cartoon highlights a major misconception about Global Warming. This misconception arises when the difference between ‘climate’ and ‘weather’ is not well understood. ‘Weather’ describes the atmosphere of a specific place for a short period of time. It changes day to day and is highly unpredictable. Whereas ‘climate’ refers to the atmospheric conditions in a large place over a long period of time. Global warming is a phenomenon that is concerned with the climate as a whole and not the everyday weather. Hence, short periods of cold weather cannot be taken as an evidence against climate change. It is possible to have hot and cold extremes. However, when the weather patterns are averaged over a long time, a clear warming trend is observed. Hence the statement “This winter has lowered my concerns about global warming…” is not justified.
3) One of the first radar devices developed during World War II used microwave radiation of a specific wave range that triggers rotation of water molecules. Why was the design not successful?
Answer:
A radar works by first sending out a signal which is then bounced off an object, and then detected by a receiver. In the case of a microwave radiation radar, the microwave radiation is required to bounce off the object in order for the radar to successfully detect the object. However, the air around us consists of water vapour. Upon contact with the microwave radiation, the water molecules will absorb the microwave radiation, and no return signal can be detected. The water molecules prevents the microwave radiation from reaching the object and bouncing back. Hence, the radar is unsuccessful.
4) Now that you have studied air quality (Unit 1), stratospheric ozone depletion (Unit 2), and global warming (Unit 3), which do you believe poses the most serious problem for you in the short run. In the long run?
Answer:
In short run, our group believes that air pollution poses the most serious problem as it’s effects were direct and widespread.
As air pollution is able to be easily transported, it will result in a domino effect on the global population. One example is the recent haze caused by burning of forests in Indonesia which affected its neighbouring countries, including Singapore whereby the people have to wear mask to filter the air they breathe. Furthermore, air pollution affects humans’ health. According to the World Health Organization, air pollution led to a rise in mortality rates, with up to around 7 million peoples deaths. These evidence showed that the problem of air pollution is devastating and it is critical to address such a crisis.
However, the effects of global warming and stratospheric ozone depletion were not immediate. Since global warming is caused by air pollution, addressing the root of the problem, would be more effective. For global warming to occur, it takes time for an extensive amount of greenhouse gas to accumulate and not only that, its effects such as increase in average global temperatures, polar ice caps melt and sea level rise occurs gradually. Hence the problem only aggravates after a significant time period.
Stratospheric ozone depletion would pose the most serious problem in the long run. Ozone depletion is due to the use of CFCs destroying the ozone layer. Furthermore, many of the CFCs are able to penetrate the stratosphere in about 5 years, hence, the effects of ozone depletion would take a much longer time as compared to daily and direct air pollution effects. Also, the CFCs can persist for 120 years in the atmosphere. which means that once CFCs is being emitted, it would affect the ozone for up to 120 years. Given our limitations in technological capabilities, repairing the ozone would be almost an impossible task. The stratospheric ozone layer also protects all life-forms on Earth. Without it, we might have to find another planet to live on, which so far, none of them proves to be able to support life.