What chemical would only be present in 10 per mL? A mL of water has ~10^22 water molecules in it. Dilute substances are usually measured in ppm (parts per mill

What chemical would only be present in 10 per mL? A mL of water has ~10^22 water molecules in it. Dilute substances are usually measured in ppm (parts per million). Even 1 ppm would have 10^16 molecules. I think your orders of magnitude are way off here.