Lab: Solution Preparation Protocol
Revised 12/16/10
Name _______________________________________Date _____________ Period _________ Score ______
MATERIALS NEEDED:
electronic balance, funnel, 3 weighing boats, 10ml graduated cylinder, 100ml graduated cylinder, 500 ml
graduated cylinder, 100ml volumetric flask, orange topped bottles, sodium chloride, Sucrose (sugar), 500x fast
blast DNA stain, 10x Tris/Glycine/SDS Buffer , and 50x TAE Buffer.
INTRODUCTION
In biotechnology we will be making and using many different concentrations of solutions. Many of these
solutions will be made from powdered chemicals. To create these solutions we will need to know the molar
mass of the substance and figure out the number of grams to add to the solvent. See the example below:
Example 1
Create a 1.00 L of a 0.50 M KCl solution.
Molarity (M) = Number of Moles of Solute
Solution Volume (Liter/s)
1. Calculate the molar mass of potassium chloride.
Potassium + chloride = 39.10 g/mole + 35.45 g/mole = 74.55 g/mole
2. Calculate the amount of KCl need to prepare 1.00 L of a 0.50 M solution.
Mass of Solute = Solution Volume (Liters) x Molarity (mole/liter) x Molar Mass (g/mole)
Solute needed = 1 liter x 0.50 M x 74.55 g/mole = 37.28 g
3. Calculate the number of moles of potassium chloride in the given solution.
37.3 g ÷ 74.55 = 0.5 moles
Example 2
Create a Solution 250 ml of 10 % Sugar water.
Weight/Volume % =
weight of solute x 100
100 mL of solution
4. Calculate the mass of sugar needed
Grams of solute = Volume of solution x W/V %
Grams of sugar = 250 mL x 10%
Grams of sugar = 25 g
5. Explain how you will make the solution
 Mass out 25 grams of sugar in weigh boat.
 Pour into volumetric flask.
 Fill to 250 ml mark with water.
Dilution
Scientists often make a solution of a higher concentration than is needed for a procedure called a stock solution.
These stock solutions are diluted to lower concentrations for use in laboratory protocols. To dilute a solution
scientists add more solvent (usually water) without the addition of more solute. This lowers the overall
concentration of the solution. Because the amount of solute remains the same for both solutions, the amount of
solute is the same for both solutions. Therefore, the number of moles before dilution = the number of moles
after dilution.
Molarity (M) x Volume (Liters) = Number of Moles of Solute in solution 1
Molarity (M) x Volume (Liters) = Number of Moles of Solute in solution 2
Because the # of moles is equal, we can set the two equations equal to each other.
Molarity1 x Volume1 x = Molarity2 x Volume2
M1V1 = M2V2
or more generally
C1V1 = C2V2
Example 3
You have made 53.3 mL a stock solution of 1.5 molar solution of potassium chloride. Your laboratory protocol
requires a 0.8 molar potassium chloride solution for the procedure. Prepare the 0.8 molar solution needed by
dilution.
M1V1 = M2V2
1.5 M x 53.3 mL = .5 M x V2
1.5 M x 53.3 mL = V2
.8 M
99.938 ml = V2
Example 4
You have a stock solution of 95% ethanol. Your laboratory protocol requires 25 mL a solution of 20% ethanol
for the procedure. How would you prepare the 25ml 20% ethanol solution needed by dilution?
1. Calculate the volume of stock solution needed:
M1V1 = M2V2
95% x V1 = 20% x 25 mL
V1 = 20% x 25 mL
95%
V1 = 5.26mL
2. Determine the amount of water to add to the solution to make the 25 mL needed.
25ml - 5.26ml = 19.74ml
3. Make the solution.
X = 5.26 ml of 95% ETOH + 19.74 ml H2O
Procedure
A. Create a Solution 100 ml of 10 % Sugar water. m/v
1. Calculate the mass of sugar needed
2. Explain how you will make the solution
B. Create a Solution 100 ml of 40 % Sugar water. m/v
1. Calculate the mass of sugar needed
2. Explain how you will make the solution
C. Create 100 ml 1.5M sodium chloride Solution for a stock solution.
1. Calculate the molar mass of sodium chloride.
2. Calculate the amount of NaCl need to prepare 100 mL of a 1.50 M solution.
3. Calculate the number of moles of sodium chloride in the given solution.
4. Explain how you will make the solution.
D. Using the 1.50 M sodium chloride stock solution, prepare 50 mL a solution of .6 M sodium chloride.
1. Calculate the volume of stock solution needed:
2. Determine the amount of water to add to the solution to make the 50 mL needed.
3. Explain how you will make the solution.
E. Using 50x TAE Buffer stock solution, prepare 300 mL a solution of 1x TAE Buffer.
1. Calculate the volume of stock solution needed:
2. Determine the amount of water to add to the solution to make the 300 mL needed.
3. Explain how you will make the solution.
F. Using 10x Tris/Glycine/SDS Buffer stock solution, prepare 200 mL a solution of 1x Tris/Glycine/SDS
Buffer.
1. Calculate the volume of stock solution needed:
2. Determine the amount of water to add to the solution to make the 200 mL needed.
3. Explain how you will make the solution.
G. Using 500x Fast Blast DNA Stain stock solution, prepare 20 mL a solution of 25x Fast Blast DNA
Stain.
1. Calculate the volume of stock solution needed:
2. Determine the amount of water to add to the solution to make the 20 mL needed.
3. Explain how you will make the solution.
SOLUTION CALCULATIONS PRACTICE PROBLEMS
1. How many micrograms of DNA are needed to make 100 uL of 100ug/mL solution?
2. How would you prepare 100mL of an aqueous solution of AgNO3 of strength 0.1 g AgNO3/mL?
3. How many milligrams of NaCl are present in 50mL of a solution that is 2 mg/mL NaCl?
4. How would you prepare 5 mL of proteinase K at a concentration of 100ug/mL?
5. How much solute is required to prepare 1 L of a 1 M solution of copper sulfate solution? CuSO4
6. How much solute is required to prepare a 1 L solution of NaCl of molarity 2.5?
7. How much solute is required to prepare 300 mL of a 0.800M solution of calcium chloride?
8. How would you make 100 mL of a 10% by volume solution of ethanol in water? v/v
9. How would you prepare 500 mL of a 5% solution of NaCl? w/v
10. How much solute is required to make 600mL of a 0.4 M solution of Tris buffer? (FW of Tris base is 121.10)