Answer:
3.10 × 10⁻⁴ mg
Step-by-step explanation:
In the Minnesota Department of Health set a health risk limit for benzene in groundwater of 10.0 μg/L. Suppose an analytical chemist receives a sample of groundwater with a measured volume of 31.0 mL. Calculate the maximum mass in milligrams of benzene which the chemist could measure in this sample and still certify that the groundwater from which it came met Minnesota Department of Health standards. Be sure your answer has the correct number of significant digits.
Step 1: Given data
- Concentration limit (C): 10.0 μg/L
- Volume of the sample (V): 31.0 mL
Step 2: Convert "V" to L
We will use the conversion factor 1 L = 1000 mL.
31.0 mL × 1 L/1000 mL = 0.0310 L
Step 3: Calculate the maximum mass of benzene (m)
We will use the following expression.
m = C × V = 10.0 μg/L × 0.0310 L = 0.310 μg.
Step 4: Convert "m" to mg
We will use the conversion factor 1 mg = 1000 μg.
0.310 μg × 1 mg/1000 μg = 3.10 × 10⁻⁴ mg