Question 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.
- What is the connection between coal-fired plants and poor visibility?
- 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.
Answer:
- Coal-fired plants releases sulfur dioxide. This results in sulfate particles to be present in the atmospheric air near the plant, and thus contributing to the poor visibility at the park.
- Generally, rainfall is of pH range of 5-6. Therefore, given that the average rainfall in Mammoth Cave National Park is 10 times more acidic than natural, its rainfall should be in the pH range of 4-5.
Question 2. Here are examples of what an individual might do to reduce acid rain. For each, explain connection to producing acid rain.
- Hang your laundry to dry it.
- Walk, bike, or take public transportation to work.
- Avoid running dishwashers and washing machines with small loads.
- Add additional insulation on hot water heater and pipes.
- Buy locally grown produce and locally produced food.
Answer:
- Hanging your laundry to dry uses less energy as compared to using an electrical dryer to dry it.
- Walking, biking or taking public transport can reduce the amount of gasoline used.
- It uses less energy running dishwashers and washing machines only when they are fully loaded as opposed to running them in small loads.
- Adding additional insulation on hot water heaters and pipes can prevent heat loss and conserve energy. Therefore, electrical energy generated from the burning of coal in power plants can be conserved.
- Buying from locally grown produce and locally grown feed will greatly reduce the amount of gasoline used in transporting externally-grown produce. Therefore, less NO emission will be produced, contributing less to the acidity of the rain.
Question 3a. Give names and chemical formulas for five acids and five bases.
Answer:
Five acids:
- Nitric acid, HNO3
- Hydrochloric acid, HCl
- Sulfuric acid, H2SO4
- Phosphoric acid, H3PO4
- Carbonic acid, H2CO3
Five Bases:
- Sodium hydroxide, NaOH
- Potassium hydroxide, KOH
- Ammonium hydroxide, Nh4OH
- Magnesium hydroxide, Mg(OH)2
- Calcium hydroxide, Ca(OH)2
Question 3b. Name three observable properties generally associated with acids and bases.
Answer:
Properties of Acid:
- Taste sour
- Turn litmus paper red
- Release carbon dioxide from a carbonate.
Properties of Base:
- Taste bitter
- Turn litmus paper blue
- Slippery feel in water
Question 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?
- http://www.ec,gc,ca/
- http://www.ukawmn.ucl.ac.uk/
- http://www.grida.no/
- http://www.nea.com.sg /
Answer: One issue that Singapore is facing is the impact of biomass burning on rainwater acidity and composition. Large scale forest fires in Indonesia, to clear land and make way for new harvest, are being set from August to October every year. This process releases large amount of gaseous and particulate pollutants into the atmosphere, and adversely affected the air quality in Southeast Asia region. A study done in 1997 revealed that major inorganic and organic ions (SO42-, NO3– and NH4+) were detected in the collected rain samples, and the acidity of this rain were between the pH values of 3.79 to 6.20. The decrease in pH of precipitation in response to the increased concentration of acids is marginal, due to the neutralisation of acidity by NH3 and CaCO3.