### Whiteboard Practice - Belle Vernon Area School District

```Solutions Review
Play as a slideshow!
Calculate the molarity of a 0.175 L sugar
solution that was prepared with 0.15 moles of
sugar?
• M = mol/L
• M = 0.15 mol/0.175 L
• M = 0.86 M
Solutions are ________________ mixtures
made up of very small particles.
• Homogeneous
Determine the volume of 0.235 M sugar solution
that can be prepared with 0.470 moles of sugar.
• M = mol/L
• 0.235 M = 0.470 mol/ x L ***cross-multiply
• 0.235 x = 0.470
• X = 2.00 L
Explain why solutions are classified as mixtures
• The two parts, solute and solvent, are only
physically combined, not chemically
combined. Also, you can easily separate them
with a physical change, such as evaporating
off the solvent. Finally, they can combine in
different ratios, they do not have a fixed ratio
like compounds (example, water is always 2 H
and one O, but salt water can have varying
percent of salt in it).
A salt solution is to be added to a marine
aquarium. Calculate the molarity of a salt
solution that is prepared by adding water to
18.65 g of NaCl to give a final volume of 250.0
ml.
• M = mol/L
• 18.65 g x 1 mol/ 58.44 g = 0.3191 mol
• M = 0.3191 mol/0.2500 L
• M = 1.277 M
Pure gold is 24 carat. 14-carat gold contains 14
parts gold and 10 parts other metals. 14-carat
gold is said to be a(n) ___________,
which is a
alloy
type of solution. An example of a gaseous
air
solution is ________________,
oxygen
up mostly of ______________
and nitrogen
when dry. The most common solutions are
______________
solutions.
aqueous
Calculate the volume of a 3.15 M NaOH (aq)
solution that should be used to prepare 250. ml
of 0.150 M NaOH (aq).
• M1V1 = M2V2
• 3.15 M x V1 = 0.150 M x 250. mL
• V1 = 11.9 mL
Because of the _______________
_______________, you can see the light beams
from car headlights in a fog.
• Tyndall Effect
You have 3.0 L of 3.0 M HCl. What volume of 2.0
M HCl can you make?
• M1V1 = M2V2
• 3.0 M x 3.0 L = 2.0 M x V2
• V2 = 4.5 L
3.5 L of solvent was added to 2.0 L of a 0.88 M
solution. What is the new molarity of the
solution?
• M1V1 = M2V2
• 0.88 M x 2.0 L = M2 x 5.5 L
• M2 = 0.32 M
Multiple choice: To increase the rate of solution
of a solid in water,
• a. increase the pressure over the water.
• b. decrease the pressure over the water.
• c. crush the particles of the solid.
• d. chill the water.
You need 450 mL of 0.15 M NaOH. All you have
available is a 2.0 M stock solution of NaOH.
What volume of solvent will you add to the
volume required of the stock solution to make
• M1V1 = M2V2
• 0.15 M x 450 mL = 2.0 M x V2
• V2 = 33.75 mL stock solution
• 450 – 33.75 = 416.25 mL solvent
• If 15 grams of iodine are dissolved in 1000 mL
of alcohol, the alcohol is the (solute, solvent)
and the solution is said to be a(n)
tincture
_______________.
• A substance that dissolves other materials is a
(solute, solvent). The substance being
dissolved is a (solute, solvent).
You have 6.0 L of 5.0 M NaCl stock solution. You
take 800 mL of that stock solution, and add 500 mL
of solvent.
-How many moles of NaCl would be present in the
new solution?
-What is the molarity of new solution?
• M = mol/L
• 5.0 M = x mol/ 0.800 L
• X = 4.0 mol
• M1V1 = M2 V 2
• 5.0 M x 800 mL = M2 x 1300 mL
• M2 = 3.08 M
• In (solutions, suspensions) the substances
separate after standing a while. The
substances (can also, can not) be separated by
filtration.
Find the volume of a 0.75 M solution if it
contains 39 grams of KOH.
• 39 g x 1 mol/56.1 g = 0.695 mol
• M = mol/L
• 0.75 M = 0.695 mol/x L ***cross-multiply***
• X = 0.927 L
• Smoke is an example of a _____________ of
solid dirt and dust particles in air.
• colloid
How many grams of hydrochloric acid (HCl) are
present in 3.0 L of a 0.750 M solution?
• M = mol/L
• 0.750 M = x mol/ 3.0 L
• X = 2.25 mol
• 2.25 mol x 36.45 g/ 1 mol = 82.0 g
• A(n) ________________’s particles are
between those of a solution and a suspension.
• colloid
110.0 mL of 3.00 M sulfuric acid has 25.0 mL of
water added to it. What is the resulting
concentration of the solution ?
• M1V1 = M2V2
• 3.00 M x 110.0 mL = M2 x 135.0 mL
• M2 = 2.44 M
• How does a solution behave differently from a
suspension when a beam of light is shined
through it?
• A beam of light will go right through a solution
and you will not see it. A suspension exhibits
the Tyndall Effect where you will be able to
see the beam of light.
Acetic acid is purchased as a solution in 17.0 M
concentrations. Explain how you would
prepare 500.0 mL of a 5.00 M solution.
• M1V1 = M2V2
• 17 M x V1 = 5.00 M x 500.0 mL
• V1 = 147.1 mL
• Put 147.1 mL into a 500 mL volumetric flask.
Then add water until the solution is 500 mL
total (to the line).
• What is the solute in a brass alloy containing
75% copper and 25% zinc?
• Zinc (it has a smaller percentage)
• Substances that conduct electricity when
electrolytes
dissolved are said to be ______________,
while substances that do NOT conduct
electricity when dissolved are said to be
Non-electrolytes
__________________.
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