Question

Your problem: Show how you would make 2 liters of a 20% glucose solution.

Before you solve the problem organize you thoughts on paper in the following manner (Show all work!!):

What will my answer look like? What units will I be using?

What do I need to know before I can start solving this problem? Do I know what the word “solution” means? Do I know what “% solution” means?

What is known (given in the problem)??? How many liters will I make? What will be in the solution?

How should I set up the problem. Will an illustration help me??

How do I know when I am finished??? Do I have the correct units? Did I circle my final answer.

Answer 1

% solution is defined as grams of solute per 100 ml or 100 g of a solution. It can either be w/v or v/v
but this calculation which is performed below will be w/v % .
( x gm / 100 mL ) *100 = 20 %
x gm = 20 gm = 20 gm of glucose must be dissolved in 100mL of the solvent to make up 20% solution
But we should make 2L of solution,
20 gms -------- 100 mL
? gms ------------ 2000 mL or 2L
Cross multiply to get the answer which is (2000mL * 20 gms) / 100mL = 400 gms
So 400 gms of glucose should be dissolved in 2L of water to make 20% (w/v) solution