# Numerical: How will you make a 0.35 M glucose solution? Also, prepare a 0.12 M solution of glucose from the above stock.

##### 2 Answers

We first work out the molar mass of glucose,

#### Explanation:

So for one liter we need

If you want a given volume

(the method is called reverse ratio)

Use glucose's molar mass and the target solution's molarity.

#### Explanation:

To make calculations easier, you can always assume your stock solution to have a volume of **1.0 L**.

Since the molarity of the stock solution must be equal to **0.35 M**, the sample must contain **0.35 moles** of glucose.

Determine how many grams of glucose would contain this many moles by using the compound's molar mass

So, to prepare a **0.35-M**, **1.0-L** stock solution of glucose you must dissolve **63 g** of glucose in enough water to make the total volume equal to one liter.

To prepare a **0.12 M** solution from the stock solution, you need to determine exactly what volume of the stock solution would contain **the same number of moles** of glucose as the stock solution.

This is where the equation for dilution calculations comes in handy.

In your case, you have

So, to make a **0.12-M** solution out of your stock sample, add enough water to get the total volume of the solution to **2.9 L**, i.e. add 1.9 L of water.