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Multiple Choice
When lead levels in blood exceed 0.80 ppm (parts per million) the level is considered dangerous. 0.80 ppm means that 1 million g of blood would contain 0.80 g of Pb. Given that the density of blood is 1.060 kg/cm3, how many grams of Pb would be found in 400.00 mL of blood at 0.620 ppm?
A
0.891 g Pb
B
0.522 g Pb
C
0.263 g Pb
D
0.059 g Pb
Verified step by step guidance
1
First, understand that ppm (parts per million) is a way to express very dilute concentrations of substances. In this context, 0.620 ppm means 0.620 grams of lead (Pb) per 1,000,000 grams of blood.
Convert the volume of blood from milliliters to cubic centimeters, knowing that 1 mL = 1 cm³. Therefore, 400.00 mL of blood is equivalent to 400.00 cm³.
Use the density of blood to convert the volume of blood to mass. The density is given as 1.060 kg/cm³, which means 1 cm³ of blood has a mass of 1.060 kg. Convert this to grams (1 kg = 1000 g) to find the mass of 400.00 cm³ of blood.
Calculate the mass of lead in the blood using the concentration in ppm. Multiply the mass of the blood (in grams) by the concentration of lead (0.620 ppm) and divide by 1,000,000 to find the mass of lead in grams.
Finally, compare the calculated mass of lead to the given options to determine which one matches the calculated value.