Unit 6: Neutralizing the Threat of Acid Rain

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Questions for CM8001-AE 5

1.Mammoth Cave National Park in Kentucky is in close proximity to the coal-fired electric utility plants in the Ohio Valley. Noting this, this National Parks Conservation 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?

b. The NPCA reported ” the average rainfall in Mammoth Cave National Park is 10 times more acidic than natural.” From this information and that in your text, estimate the pH of rainfall in the park.

(A) Coal-fired plants release sulfur dioxide, resulting in sulfate particles forming in the air. Sulfates are the largest contributor to haze in the eastern U.S. due to the region’s large number of coal-fired power plants. Furthermore, sulfate particles grow rapidly to a size that is very efficient at scattering light in humid environments. This worsens the problem in the east and hence, sulfates are responsible for 60 to 85 percent of the poor visibility in eastern parks.

(B) Normally, clean rain has a pH value of between 5.0 and 5.5, which is slightly acidic. However, when rain combines with sulfur dioxide or nitrogen oxides (produced from coal-fired plants in this context), the rain becomes much more acidic. With the rainfall in the park being 10 times more acidic than natural, the estimated pH of the rainfall would be between 4.0 to 4.5 which is typical of acid rain.

2. Here are examples of  what an individual might do to reduce acid rain. For each, explain connection to producing acid rain.

a. Hang your laundry to dry it.

b. Walk, bike, or take public transportation to work.

c. Avoid running dishwashers and washing machines with small loads.

d. Add additional insulation on hot water heater and pipes.

e. Buy locally grown produce and locally produced food.

 

(A) When you hang your own laundry, we do not need to use the dryer. Hence, we save electricity which in turns cut down on energy usage. Power plants in Singapore can then cut down on the burning of coal to generate electricity, causing lesser sulfur dioxide to be released into the air.

(B) By walking, taking public transportation or using a bike to get to work, it reduces the amount of car usage.  As there are lesser car usage, it leads to lesser NO emissions and thus contributing less to the acidity of the rain.

(C) Similarly to part (A), by washing the dishes manually, it eliminates the need to use machines which requires energy to work. Hence, energy consumption is reduced and power plants do not need to burn as much coal to supply the required energy. As a result, lesser coals are burned and lesser sulfur dioxide is released into the air.

(D) By insulating hot water heater and pipes, it reduces energy consumption as Insulated pipes reduces heat loss and can raise water temperature 2°F–4°F hotter than non-insulated pipes. As a result, water is heated up faster and lesser energy is required to do the same task. As mentioned earlier in part (A) and (C), power plants do not need to burn as much coal to supply the required energy. As a result, lesser coals are burned and lesser sulfur dioxide is released into the air.

(E) Tremendous amount of fuel is used to transport foods long distances and combustion of fuels releases carbon dioxide, sulfur dioxide, particulate matter and other pollutants into the atmosphere, causing acid rain. Hence, by buying locally grown food, lesser fuel is used to transport food from overseas, resulting in a reduction in NO emission, thus contributing less to the acidity of the rain.

 

3.

a. Give names and chemical formulas for five acids and five bases.

Acids

  1. Hydrochloric acid (HCl)
  2. Sulfuric acid (H2SO4)
  3. Hydrobromic acid (HBr)
  4. Nitric acid (HNO3)
  5. Phosphoric acid (H3PO4)

Bases

  1. Sodium hydroxide (NaOH)
  2. Calcium hydroxide (Ca(OH)2)
  3. Potassium hydroxide (KOH)
  4. Ammonium hydroxide (NH4OH)
  5. Magnesium hydroxide (Mg(OH)2)

b. Name three observable properties generally associated with acids and bases.

Acids are typically corrosive and produces carbon dioxide when reacted with metals. It tastes sour and turns blue litmus paper red, due to the acidic pH.

Bases are usually soapy and caustic to skin. It turns red litmus paper blue due to the high pH(basic) and tastes bitter.

 

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 links to websites in Canada, the UK, or Europe. What are the issues in Singapore? Does the acid deposition originate outside or inside the Singapore’s borders?

URL: 

http://www.ec,gc,ca/

http://www.ukawmn.ucl.ac.uk/

http://www.grida.no/

http://www.nea.com.sg /

 

According to the NUS study, Acid rain in Singapore could force native species into extinction. Acid rain has caused the pH in rivers and ponds in Singapore to reduce to 4.4-4.7 pH. Creatures living in Singapore are currently under stressed and  may eventually not be able to cope with the environment and succumb to death. The increase in acidity is mainly caused by the expansion of industry plants  which has led to the rise of sulfur dioxide emission, driving the increase in acid rain.

Both sides of the border play a role in acid deposition in Singapore. Industrial plants, power plants and burning of fossil fuels in Singapore will result in acid deposition. On the other hand, the  recent haze issues caused by our neighboring countries has also contributed to the acid deposition. Aerosols found in haze adds to the formation of acid rain which eventually decreases the pH of water found in rivers and ponds in Singapore.

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