# Question #ca68c

##### 1 Answer

You'd have to use **5 mL** of **5 M** sucrose and **95 mL** of water.

A very useful tool to have when doind dilution calculations is the **dilution factor** - read more here:

http://socratic.org/questions/how-do-you-calculate-dilution-factor?source=search

The dilution factor will tell you by what factor you've diluted the original sample. In your case, you need to go from a concentration of **5 M** to a concentration of **0.25 M**.

You need the dilution factor to be equal to **20**, since a molarity of 0.25 M is *20 times smaller* than a molarity of 5 M.

The dilution factor is defined as the final volume of the solution divided by the initial volume of the sample

Check to see which of your solutions would give you a dilution factor of 20

This volume ratio is too high.

The volume ratio is till too high, move on to the next solution.

There it is. If you mix **5 mL** of a **5-M** sucrose solution with enough water to make the final volume equal to **100 mL** (with 95 mL of water, to be precise), you'd get **100 mL** of a **0.25-M** solution. solution