Problem 114 - Chemistry The Molecular Science

Question

In April 2010 the main pipe of the Deepwater Horizon oil-drilling platform burst, spewing crude oil into the Gulf of Mexico. On April \(25,2010,\) the spilled crude oil that reached the surface of the Gulf formed an oil slick \(120 \mathrm{nm}\) thick covering an area of \(1.5 \times 10^{3} \mathrm{~km}^{2}\). Calculate the number of barrels of crude oil in this slick; 1 barrel \(=42\) gal.

Step-by-Step Solution

Answer

Approximately 1132 barrels of crude oil were in the oil slick.

Step 1: Convert Area Units

First, convert the area of the oil slick from square kilometers to square meters. We know that:\[1 \text{ km}^2 = 10^6 \text{ m}^2\]Therefore, the area of the oil slick is:\[1.5 \times 10^{3} \text{ km}^2 = 1.5 \times 10^{3} \times 10^{6} \text{ m}^2 = 1.5 \times 10^{9} \text{ m}^2\]

Step 2: Convert Thickness Units

Next, convert the thickness of the oil slick from nanometers (nm) to meters. We know that:\[1 \text{ nm} = 10^{-9} \text{ m}\]Therefore, the thickness of the oil slick is:\[120 \text{ nm} = 120 \times 10^{-9} \text{ m} = 1.2 \times 10^{-7} \text{ m}\]

Step 3: Calculate Volume of Oil in Cubic Meters

Now, calculate the volume of oil by multiplying the area by the thickness:\[\text{Volume} = \text{Area} \times \text{Thickness}\]\[\text{Volume} = 1.5 \times 10^{9} \text{ m}^2 \times 1.2 \times 10^{-7} \text{ m}\]Perform the multiplication:\[\text{Volume} = 1.8 \times 10^{2} \text{ m}^3\]

Step 4: Convert Cubic Meters to Gallons

We need to convert the volume from cubic meters to gallons. We know:\[1 \text{ cubic meter} = 264.172 \text{ gallons}\]So, the volume in gallons is:\[1.8 \times 10^{2} \text{ m}^3 \times 264.172 \text{ gallons/m}^3 = 47551.56 \text{ gallons}\]

Step 5: Convert Gallons to Barrels

Finally, convert the volume from gallons to barrels. We know:\[1 \text{ barrel} = 42 \text{ gallons}\]So, the volume in barrels is:\[\frac{47551.56 \text{ gallons}}{42 \text{ gallons/barrel}} \approx 1132.18 \text{ barrels}\]

Step 6: Conclusion

Thus, the number of barrels of crude oil in the slick is approximately 1132 barrels.

Key Concepts

Understanding Unit Conversion

Unit conversion is a fundamental skill in many scientific disciplines, including environmental chemistry. It involves changing measurements from one unit to another, often using conversion factors. In the context of an oil spill, it’s crucial to convert measurements to a common unit to perform calculations accurately. For example, the area of the oil slick can be measured in square kilometers (km²), but for precise calculations, it may be more practical to convert this to square meters (m²). This is because a square kilometer is a much larger unit and might make the numbers cumbersome to work with directly.

• 1 km² is equal to 1,000,000 m².
• Understanding that 1 nanometer equals 10^-9 meters also helps in understanding thickness on a relatively microscopic scale.

By using these conversions, you ensure that every part of your calculation is using compatible units, making your final result understandable and precise.
Knowledge of unit conversion allows you to bridge the gap between various scales such as length, area, and volume with ease.

Volume Calculation for Oil Spills

Volume calculation is another critical component when assessing the impact of environmental events like oil spills. The volume of an oil spill is typically derived from the product of the spill's surface area and thickness. This can initially seem abstract, but let's break it down. Imagine you have a thin sheet of oil spreading over a large area. To understand how much oil there actually is, we multiply:

• The area where the oil is spread, which is given in m²
• The thickness of the oil layer, which is given in meters

To calculate the volume of oil on the surface:

• You take the converted area and multiply it by the converted thickness.
• The result gives you the volume in cubic meters (m³).

This simple multiplication gives us insight into the quantity of oil present. By converting this volume into a more familiar unit like gallons or barrels, we make the results more meaningful for those interpreting the data.

Environmental Chemistry and Its Relevance

Environmental chemistry is the study of chemical processes occurring in the environment, including those that are the result of human activity. Oil spills are a significant concern within this field because they bring about chemical and physical changes in the environment. The release of crude oil into the seas affects marine life, coastlines, and can lead to far-reaching ecological damage. Understanding these chemical processes helps us:

• Assess the immediate and long-term impacts of spills.
• Design effective response strategies to minimize harm.

In the case of an oil spill, knowledge of the quantity and spread of oil enables scientists and engineers to:

• Predict the movement of the spill using currents and weather patterns.
• Implement clean-up measures like skimmers, which remove oil from the water's surface.

The convergence of unit conversion and volume calculation in environmental chemistry provides a framework for effectively managing and mitigating these environmental hazards.