1. Chemical Solution Preparation
Biotechnology I
Chemical Solution Preparation
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2. Essential Questions What are the components of a solution
How is a solution’s density defined?
How is solution concentration defined?
What are common concentration units used for making chemical solutions?
How is concentration calculated?
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3. Solution: What is a 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 dissolved in the solution (usually what is measured out).
Example – glucose, NaCl
Solvent: The substance that does the dissolving.
Example: water – universal solvent
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5. 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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6. Units Important in Solution Preparation
Common units
Volume –L, mL, mL
Mass – kg, g, mg, mg
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7. Definition of Mole
A unit of measurement or 6.023x1023 somethings used in chemical quantity expressions
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8. 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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9. 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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10. Molar Mass Determination
Obtained from chemical label on stock bottle
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11. 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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12. In order to convert between mass and volume the density of a substance needs to be known.
Many times found on a stock chemical label.
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13. Density Calculation Triangle Trick
Density = Mass / volume
Mass = Density X Volume
Volume = Mass / Density
To use the triangle trick, cover
up the unit you want to calculate
and then perform the mathematical operation either multiplication or division
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14. Solution Concentration- Units of Measurement
Biotechnology I

15. Concentration
Concentration: The amount of substance in a defined space or volume
Defined space or volume
Amount of substance

16. Common Concentration Units: Percent (%)
Two types commonly used in Biotechnology:

17. SOP for Making w/v % Solution
Convert (w/v) % to a decimal
Convert volume to mL
Multiple the decimal x the total volume to determine how much solute to weigh out
Dissolve solute in small amount of water
Bring to final total volume with water in graduated cylinder
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18. Common Concentration Units- Molarity
SOP for Making a Molar solution
Determine final volume needed and convert unit to L
Determine final concentration and convert to Molarity
Determine the molar mass of the solute either determined from periodic table or taken from chemical stock bottle
To determine mass use the following calculation
g of powder = Molar Mass X Concentration ( in M) X Volume (in L)

19. Solution Preparation Equipment
Here are some of the more common pieces of equipment you will use to make solutions
Graduated cylinder
Balance
Magnetic stir plate and bar
Pipets
Beakers
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20. Making Solutions: Cautions
Mixing order:
Always add Acids or Bases to water.
Never add water to Acids or Bases
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