An analytical chemist wants to measure the concentration of lead in drinking water in their building. They dilute 1mL of the sample to 100mL of ultrapure water, then acidified (acidification does not affect concentration. It is just a step to make sure the metals are dissolved in the water) and quantified the metal concentration by Inductively coupled plasma - optical emission spectrometry. The result of the diluted sample measured 0.5ppm Pb. Which of the following represents the concentration of the undiluted sample? Is this water safe to drink? (select one or more) a. 50 ppb
b. 50 ppm
c. 2 x 10-4 M
d. 2 x 10-4 % mass
e. 5 ppm
f. 5 ppb
g. 5 x 10-4 M
h. 5 x 10-4 % mass
i. Yes
j. No