Question 1: Explain in your own words what atmospheric pollutants emitted by automobiles are and why they are a concern for environmental health.

Answer: Automotive atmospheric pollutants are harmful substances released into the air from vehicle exhaust, such as carbon monoxide, nitrogen oxides, hydrocarbons, and sulfur compounds. They contribute to air pollution, smog formation, acid rain, and health problems like respiratory issues.

Question 2: Name three primary pollutants commonly found in vehicle exhaust gases.

Answer: Carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons (HC), sulfur dioxide (SO2).

Question 3: What is the main chemical process responsible for the formation of nitrogen oxides in vehicle engines?

Answer: High-temperature combustion causes nitrogen and oxygen in the air to react, forming nitrogen oxides (NO and NO2).

Question 4: Fill in the blank: The primary sulfur compound emitted from diesel engines is __________.

Answer: sulfur dioxide (SO2)

Question 5: Multiple Choice: Which of the following is NOT a typical component of vehicle exhaust?

Answer: Ozone (O3)

Question 6: Describe one method used to reduce nitrogen oxides emissions from automobiles.

Answer: One common method is the use of catalytic converters, which facilitate chemical reactions that convert nitrogen oxides into nitrogen and oxygen gases, reducing NOx emissions. Selective Catalytic Reduction (SCR) systems use a reagent like urea to convert NOx into nitrogen and water.

Question 1: Calculate the mass of sulfur dioxide emitted if a diesel vehicle releases 0.05 kg of sulfur per 100 km, assuming complete oxidation. (Atomic masses: S=32 g/mol, O=16 g/mol).

Answer: Sulfure dioxide (SO2) molar mass = 32 + (16×2) = 64 g/mol. Mass of S = 0.05 kg = 50 g. Moles of S = 50 g / 32 g/mol ≈ 1.5625 mol. Since 1 mol S produces 1 mol SO2, mass of SO2 = 1.5625 mol × 64 g/mol ≈ 100 g.

Question 2: If a car emits 0.2 grams of nitrogen oxides per kilometer, how much NOx would it emit over a 150 km trip?

Answer: Total NOx emissions = 0.2 g/km × 150 km = 30 g.

Question 1: Describe two safety precautions that should be taken when testing vehicle emissions in a laboratory setting.

Answer: Wearing proper protective gear such as gloves and goggles, ensuring proper ventilation in the testing area, and handling chemicals like sulfur compounds with care to prevent inhalation or skin contact.

Question 2: Identify the main variables that should be controlled during an automotive emissions experiment.

Answer: Engine temperature, engine load, fuel type, and ambient air conditions such as temperature and humidity.

Question 1: A recent study found that in a city with high vehicle traffic, the average nitrogen oxides concentration in the air is 75 parts per billion (ppb). Explain how these NOx levels can contribute to smog formation and respiratory problems.

Answer: High levels of nitrogen oxides react with volatile organic compounds in the presence of sunlight to form ground-level ozone, a major component of smog. Elevated NOx can also irritate respiratory pathways, causing or worsening asthma and other lung diseases. Continuous exposure increases health risks and degrades air quality.

Question 2: Discuss one technological advancement that has helped reduce atmospheric pollutants from modern automobiles.

Answer: The development of catalytic converters has significantly reduced emissions by converting harmful gases like CO, NOx, and HC into less harmful substances such as nitrogen, carbon dioxide, and water. Additionally, advancements like electric vehicles eliminate tailpipe emissions altogether, greatly improving air quality.