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

Question

my answer was 0.9g
my formula 0.09/1000=90
90/100= 0.9
which answer should of been 90mg

Answer 1

Your formula is correct, but your conversion is not.

9% w/v means 9 grams of active ingredient per 100 mL of solution.

So if you have 1 L of solution (1000 mL), you would have 9 grams of active ingredient.

If you have 100 mL of solution, you would have 0.9 grams of active ingredient.

Therefore, the answer is 0.9g of active ingredients in a 9% w/v solution.