Multiple ChoiceAmphetamines in urine can be confirmed by mass spectrometry at a concentration of 500 ng/mL. Assuming a urine density of 1.025 g/mL, what is this concentration in parts per million (ppm)?154views
Multiple ChoiceWhat is the concentration of 0.5 g KCl in 3000 g of water in parts per million (ppm)?404views