Question 40a6a

May 20, 2017

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 $64 \times 4 = 256$ milligrams

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

May 20, 2017

$256.00$ $\text{mg}$

Explanation:

The average concentration of $\text{PCB}$s in the body tissue of a human is $4.00$ $\text{ppm}$.

Let's convert the units of the concentration from $\text{ppm}$ to $\text{mg}$ / $\text{kg}$:

⇒ 1 $\text{ppm}$ $= 1$ $\text{mg}$ / $\text{kg}$

⇒ 4.00 $\text{ppm}$ $= 4.00$ $\text{mg}$ / $\text{kg}$

We need to find the mass of $\text{PCB}$s found in a $64$ $\text{kg}$ 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 $64$ $\text{kg}$:

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

⇒ 256.00 $\text{mg}$ $= x$

∴ x = 256.00# $\text{mg}$

Therefore, the mass of $\text{PCB}$s present in a $64$ $\text{kg}$ person's body is $256.00$ $\text{mg}$.