1. Chemical Solution Preparation
Biotechnology I
Chemical Solution Preparation
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2. Essential Questions What are the components of a solution?
How are molar solutions made?
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3. What is a Solution
Solution:
A solution is a homogeneous mixture of two or more substances (solvent and solute). A solution may exist in any phase (solid, liquid, or gas).
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4. Solution Composition
Solutions are composed of at least two components.
Solute-The substance that is dissolved in the solution (usually what is measured out).
Example – glucose, NaCl
Solvent: The substance in a solution that does the dissolving.
Example: water – universal solvent
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5. Types of Solutions
Liquids: solution and its components are either dissolved, suspended, or in a liquid phase.
Gas: mixture of various gases. Example: Air
Solids: mixture of various solids. Example: concrete
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6. Types of Solutions Cont.
Homogeneous solution:
Solution composed of only one phase
Heterogeneous solution:
Solution composed of more than one phase
Which of these is a homogeneous solution?
1 or 2 1
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7. Units Important in Solution Preparation
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8. Definition of Mole
A unit of measurement or 6.023x1023 somethings used in chemical quantity expressions
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9. Why a Mole?
Because molecules that make up biological and chemical solutions are so small, we have to work with an extremely large amount of them. Rather than use really big numbers, the value of the mole was created. 1 mole = x 1023 molecules
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10. Molar Mass When using chemicals, molar mass is used.
Molar Mass (MM): The number of grams in 1 mole
Ex. NaCl = g/mole
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11. Molar Mass determination
Determined
Chemical label on stock bottle
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12. Molar Mass determination
Looking at chemical formula and a periodic table
Ex. NaCL (chemical formula for sodium chloride)
Na has a atomic mass of g/mole
Cl has a atomic mass of g/ mole
Molar Mass determined by adding the atomic masses
= g/mole
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13. Practice Problem
Calculate the molar mass for each of the chemicals using the periodic table
CaCL2.2H2O (calcium chloride dihydrate)
NaH2PO4.H2O (sodium phosphate, monobasic)
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14. In order to convert between mass and volume the density of a substance needs to be known.
Many times this can be found on a stock chemical label.
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15. Density Calculation Triangle Trick
Density = Mass / volume
Mass = Density X Volume
Volume = Mass / Volume
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16. What volume will 2.0g of NaCl occupy, if the density of NaCl is 2.165g/ml? First what is the formula for going from mass to volume, tell your neighbor.
0.924ml
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17. What volume will 4.5g of NaCl occupy, if the density of NaCl is 2.165g/ml?
2.08ml
What mass will 1.6ml of NaCl occupy, if the density of NaCl is 2.165g/ml?
3.46g
What volume will 0.5g of gel agarose powder occupy, if its density is 1.20g/ml?
0.417ml
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18. Make solution of given strength, must determine the number of moles.
Make solution of given strength, must determine the number of moles.
Since mass is easily measured, moles can be determined by knowing the molar mass.
The MM can be found on a stock chemical label or calculated with periodic table and chemical formula.
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19. If a solution calls for 0.08moles of Iodine and the molar mass of 253.3g/mol, how much should you weigh out?
20.26g
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20. How many moles are in 3.0g of TAE if the molar mass is 101.2g/mol?
0.0296mol
If you needed 0.025moles of EDTA what mass would you use if the molar mass is 292.1g/mol?
7.30g
If you needed moles of NaOH what mass would you use if the molar mass is 40g/mol?
0.48g
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21. Making Solutions: What Volumes to Make
Choosing the appropriate volume to make: You must consider the amount needed vs. ability to accurately measure out the amount needed. Think-Pair-Share: What could limit how we measure out chemicals?
Sensitivity of scales accuracy of pipets
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22. Solution Preparation Equipment
Here are some of the more common pieces of equipment you will use to make solutions
Volumetric Flasks
Graduated cylinder
Magnetic stir plate and bar
Milligram Scales
Pipets
Beakers
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23. SOP for Making Solutions
Using dry chemicals.
1. Determine concentration and volume of solution needed.
2. Calculate amount of solute needed from solution specifications.
3. Weight out calculated amount on weigh boat.
4. Add to a beaker
5. Add small amount of solvent (at RT) to beaker until solute is dissolved
6. Pour into a graduated cylinder
7. Bring to the appropriate volume with the solvent
8. Place parafilm over top of graduated cylinder and invert to mix
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24. Making Solutions: Cautions
Mixing order:
Always add Acids or Bases to water.
Never add water to Acids or Bases
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25. IAN Assignment
Complete density and molar concentration calculation worksheet in your IANs
Get stamp when completed.
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