Question #40a6a

2 Answers
May 20, 2017

Answer:

256 milligrams

Explanation:

If we convert 64kg to milligrams, there is 64, 000, 000 mg of person (a funny concept!) as there are 1 million milligrams in a kilogram.
So, if there are four parts for each million, and there are 64 million grams, then there will be #64xx4=256# milligrams

Hope this helps; let me know if I can do anything else:)

May 20, 2017

Answer:

#256.00# #"mg"#

Explanation:

The average concentration of #"PCB"#s in the body tissue of a human is #4.00# #"ppm"#.

Let's convert the units of the concentration from #"ppm"# to #"mg"# / #"kg"#:

#⇒ 1# #"ppm"# #= 1# #"mg"# / #"kg"#

#⇒ 4.00# #"ppm"# #= 4.00# #"mg"# / #"kg"#

We need to find the mass of #"PCB"#s found in a #64# #"kg"# human.

So let's set up a ratio using this information:

#⇒ frac(4.00 " mg")(1 " kg") = frac(x)(64 " kg")#

Multiply both sides by #64# #"kg"#:

#⇒ frac(4.00 " mg" × 64 " kg")(1 " kg") = frac(x × 64 " kg")(64 " kg")#

#⇒ 256.00# #"mg"# #= x#

#∴ x = 256.00# #"mg"#

Therefore, the mass of #"PCB"#s present in a #64# #"kg"# person's body is #256.00# #"mg"#.