Based on the above example convert 5.71 ppb into the units presented below.  
kg/μL

• A. 5.71x10^-9 kg/μL
• B. 5.71x10^-3 kg/μL
• C. 5.71x10^-15 kg/μL
• D. 5.71x10³ kg/μL

Answer: (C)

Verified step by step guidance

1. Understand that ppb (parts per billion) is a unit of concentration that represents the mass of a substance per billion parts of the solution. In this case, 5.71 ppb means 5.71 grams of substance per 1 billion grams of solution.
2. Convert the ppb value to a more manageable unit. Since 1 ppb is equivalent to 1 microgram per liter (μg/L), 5.71 ppb is equivalent to 5.71 μg/L.
3. Convert micrograms to kilograms. Since 1 μg = 1x10^-9 kg, multiply 5.71 μg by 1x10^-9 to convert it to kilograms, resulting in 5.71x10^-9 kg/L.
4. Convert liters to microliters. Since 1 L = 1x10^6 μL, divide the concentration in kg/L by 1x10^6 to convert it to kg/μL.
5. Combine the conversions: 5.71x10^-9 kg/L divided by 1x10^6 μL/L results in 5.71x10^-15 kg/μL, which matches the correct answer provided.