Problem:
The molecular weight of vincristine, a pharmaceutical drug, is 923.04 g/mol. It is supplied in 1 mg per vial. You want to treat your culture cells with a final concentration of 7 hM vincristine and will need 12 mL of cells for your experiment. You only want to add 21 mL of vincristine solution to your cells.
Question: What concentration should you make your stock solution of vincristine in order to make this 21 uL addition?