Bio Sciences: Chemicals
Biological and
Chemical Solution
Preparation
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Bellwork
One area the stockroom I audited could be
improved would by?
One area the stockroom I audited did well
was?
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Objectives
1.
2.
3.
4.
Explain what a solution is and its
components
Explain what a mole is.
Preform solution calculations
Explain the two (2) methods for making
a solution
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Terminology
Moles: A unit of measurement or 6.023x1023 somethings used in
chemical substance quantity expressions
Molar Mass: The number of grams in 1 mole
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).
Solvent: The substance in a solution that does the dissolving. Water
is the universal solvent but other solvent are commonly used in the
lab.
Solute: The substance that is dissolved in the solution
Homogenous: Solution composed of only one phase
Heterogeneous: Solution composed of more than one phase
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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).
Solutions are composed of at least two (2)
components.
Solute:
The substance that is dissolved in the solution
(usually what is measured out)
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What is a Solution cont.
Solvent:
The substance in a solution that does the
dissolving. Water is the universal solvent
but other solvent are commonly used in
the lab.
Many times isopropyl alcohol, methanol, acetone,
and ethanol are used in high school labs as
solvent.
In industry there are many organic solvents
commonly used
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Types of Solutions
Liquids:
The solution and its components are either
dissolve, suspended, or in a liquid phase. Liquid
solutions are what we will focus on.
Gas:
A mixture of various gases. Air is a good
example.
Solids:
A mixture of various solids. Concrete is a good
example
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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
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Units Important in Solution
Preparation

Name these units with
your partner and be
prepared to share
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The Mole
No not what's on your skin!
Before you get scared, what is a dozen? 12
2 000
What is a ton?
A mole is just a number of something's as well. It
is a very big number.
Mole:
A unit of measurement or 6.023x1023 somethings
used in chemical substance quantity expressions
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The Mole cont.
Because molecules that make up biological
and chemical solutions are so small in order
for us to measure them we have to work with
an extremely large amount of them.
Rather than use really big number, the value of the
mole was created.
1 mole = 602 300 000 000 000 000 000 somethings
When using chemicals molar mass is used.
Molar Mass (MM): The number of grams in 1 mole
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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.
Make sure units match up, usually the volume
unit for solids is in cm3, but we will use ml
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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.
1
Vol.  mass 
density
1ml
Vol.  2.0 g 
2.165 g
0.924ml
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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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In order to make solutions of specific strengths, the
number of moles must be known. Since we can easily
measure mass and then convert to moles that is how
moles are measured out.
For this conversion the molar mass (MM) must be known.
Many times the MM can be found on a stock chemical
label.
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Lets practice converting from moles to grams. If
a solution calls for 0.08moles of Iodine and the
molar mass of 253.3g/mol, how much should you
weigh out?
What is the formula to convert form moles to
grams?
20.26g
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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
7.30g
292.1g/mol?
If you needed 0.012 moles of NaOH
what mass would you use if the molar
0.48g
mass is 40g/mol?
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Making Solutions:
What Volumes to Make
Choosing the appropriate volume to make:
You must consider the amount needed vs.
ability to accurately make (measure out) the
amount needed.
Think-Pair-Share: What could limit how
we measure out biological and chemicals?
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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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Making Solutions:
1st Method
Using dry biologicals and chemicals.
1. Determine concentration and volume of solution
needed.
2. Calculate amount of solute needed from solution
specifications.
3. Weight out calculated amount in appropriate
volumetric flask or on weight boat.
4. Add small amount of solvent (at 25˚C) to
volumetric flask unit solute is dissolved
5. Fill with solvent drop-wise to graduated mark on
volumetric flask, insure solution is at 25˚C.
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Making Solutions:
2st Method
Same procedures as first method, but
solute is pre-dissolved in a beaker before
being added to volumetric flask.
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Making Solutions:
Cautions
Mixing order:
Always add Acids or Bases to water.
Never add water to Acids or Bases
Try not to calculate the volume of solvent
to be added, just the total volume of
solution and the add solvent until that is
reached
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Closure
Parking Lot
Use a post-it note to place questions or
concerns you have regarding todays lesson
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