A drug vial contains 500 mg of a drug in 2 ml of solution. What is its percent strength?

To determine the percent strength of the solution, you need to use the formula for percent concentration, which is calculated as the amount of drug in grams divided by the total volume of the solution in milliliters, multiplied by 100 to express it as a percentage.

1. Start with the amount of the drug in the vial, which is 500 mg. Convert this to grams since percent strength is typically expressed in grams. Thus, 500 mg = 0.5 grams.

2. The total volume of the solution is given as 2 ml.

3. Using the formula for percent strength:

[

\text{Percent Strength} = \left( \frac{\text{Amount of Drug (g)}}{\text{Total Volume (ml)}} \right) \times 100

]

4. Substitute the values into the formula:

[

\text{Percent Strength} = \left( \frac{0.5 \text{ g}}{2 \text{ ml}} \right) \times 100

]

[

= \left( 0.25 \right) \times 100

]

[

= 25\