first task is to prepare 250 ml of 3 M glucose. Then You are preparing a solution and the recipe calls for 25 ml of 10% glucose. How much of the 3M glucose stock would you need to add to so that you are adding the same molar amount of glucose?

Question

first task is to prepare 250 ml of 3 M glucose. Then You are preparing a solution and the recipe calls for 25 ml of 10% glucose.  How much of the 3M glucose stock would you need to add to so that you are adding the same molar amount of glucose?

DrBob222 · Answer

You make 3M glucose with 135 g glucose in 250 mL soln. (Check it: That is (135/180) x (1/0.250) = 3 M

25 mL of a 10% soln is how many grams. That is 10g x (25/100) = 2.5 g glucose.

So the question is how much of the 3M stuff to take to obtain 2.5g. That is
250 mL x (2.5/135) = 4.62 mL.
Check my work.