Answer:
0.0025 lbs lead in 5 lb of soil
Step-by-step explanation:
The lead is found at a concentration of 500 ppm (parts per million). We can write this as:
(500 lb Pb)/(1,000,000 lb soil) or (500 lb Pb)/(10^6 lb soil))
5 pounds of soil would therefore contain:
(5 lb soil)*(500 lb Pb)/(10^6 lb soil))
The units "lb soil" from cancel, leaving only pounds of lead.
(5 lb soil)*(500 lb Pb)/(10^6 lb soil))
(5)*(500 lb Pb)/(10^6)) = 0.0025 lbs lead