9% w/v solution has how many g of active ingredients?

Question

was a question i had on a test.
my answer is 0.9 which is not correct
should of been 90mg
what formula should of i used

Answer 1

To find the grams of active ingredient in a 9% w/v solution, you should use the following formula:

grams of active ingredient = (volume of solution in mL) × (percentage concentration / 100)

In this case, you need to know the volume of the solution to determine the grams of active ingredient. For example, if you have 100 mL of a 9% w/v solution:

grams of active ingredient = 100 mL × (9/100) = 9 grams

However, the 90 mg result you mention can be correct if you were given a specific volume of solution, such as 1 mL. In that case:

grams of active ingredient = 1 mL × (9/100) = 0.09 grams = 90 mg