PERCENT SOLUTIONS K. Bryan, I.  Gonzales, K. Kruger, M. Lowry, S. Thompson

Objective: To explain how to produce percent solutions.

Safety Considerations: To avoid accidental overdose, always label all containers

 100ml Graduated Cylinder- WW-SiO2 Distilled Water- WW-dH2O 100% Ethanol- WW-EtOH (Note-License Required For Purchase) 95% Ethanol- WW-007 (Note-Shaken, Not Stirred)

Procedure: 50 mL of 70% EtOH from 100% Ethanol*

(Note :Before you begin make sure you obtain pure water)

Step 1: Calculate the desired volume of starting solution needed to make the final percentage.

Example: A 70% EtOH solution from 100% EtOH

100%/50mL = 70%/x mL

100%*x = 50mL*70%

100%*x=3500mL%

x=35mL EtOH

Step 2: Calculate the desire amount of water to get a total volume of 50mL

50 mL - 35mL EtOH = 15 mL dH2O

Step 3: Measure 35mL of 100%EtOH and 15mL of dH2O using a 100mL graduated cylinder

Step 4: Mix the two liquids from step 3 together.

(*This would make an extra dry martini)

Procedure:  50 mL of 70% EtOH from 95% Ethanol*

Step 5: Repeat Steps #1 - 4.

Example: A 70% EtOH solution from 95% EtOH

95%/50mL = 70%/x mL

x=36.8 mL EtOH

Obtain the desired final volume (50mL) by adding the appropriate volume of dH2O (in this case, 13.2mL)
(*This would make a dry martini)