How many grams of drug does it take to make 500ml of a 1:20 solution?

To determine how many grams of drug are needed to create a 500 milliliter (ml) solution with a concentration of 1:20, it's essential to understand what this ratio means. A 1:20 solution indicates that there is 1 part drug for every 20 parts total solution.

First, let's calculate the total number of parts in a 1:20 solution. In that case, 1 part of the drug and 19 parts of a diluent (solvent) adds up to 20 parts in total.

Here is how to find the amount of drug needed for 500 ml of solution.

1. Determine the Drug Volume: With a total of 20 parts in the solution and 1 part being the drug, the drug will make up 1/20 of the total solution. To find out how much volume (or weight, since density is usually assumed to be uniform in such calculations) of the drug corresponds to 500 ml, you calculate:

[

\frac{500 \text{ ml}}{20} = 25 \text{ ml of drug}

]

2. Convert Volume to Grams: Assuming the drug has a density of