# Unit 10B Reg Chem Review

```Unit 10B Review
Reg Chem
2012-13
11
• When a solution sits out over a long period
of time and water evaporates the
concentration of the solution __________.
Increases.
As the volume of solution decreases,
the molarity (concentration) increases
12
• List an example of a solution that would
naturally dilute.
Ice in pop
13
• What does solution concentration
describe?
Molarity: amount of solute dissolved
in a given amount of solvent
14
• What do we use to describe solution
concentration in chemistry?
Molarity
15
• If a solution is “strong” it is
concentrated
• If a solution is “weak” it is
dilute
16
• What does it mean to dilute a solution?
What equation do we use for dilutions?
To lower its
concentration “water it
down” Yet keep the
number of moles the
same
M1V1 = M2V2
17
• What is the molarity of a sodium chloride
solution that contains 1.73 moles in 3.94 L
of solution?
mol 1.73mol
M

 0.439 M
L
3.94 L
18
• What is the molarity of sodium hydroxide
solution that contains 23.5 g NaOH in
500.0 mL of solution?
1mol
0.588mol
23.5 gNaOHx

 1.18M
40.00 g 0.5000 L
19
• How many grams of potassium nitrate are in 275
mL of 1.25 M solution?
x
1.25M 
 0.344mol
0.275L
KNO3
101.11g
x
 34.8 g
1mol
KNO3
20
• How many mL of 3.25 M hydrochloric acid
would contain 16.0 grams of solute?
1mol
16.0 gHClx
 0.439mol
36.46 g
3.25M 
0.439mol
 135mL
x
21
• You have 12.0 M HCl in your stock room,
how would you prepare 600.0 mL of 2.50
M HCl solution?
(12.0 M)(x) = (2.50 M)(600.0 mL)
X=125 mL
Measure out 125 mL of
mL of distilled water.
22
• How would you correctly prepare 500.0
mL of a 3.0 M solution of NaOH from solid
solute?
x
3.0M 
 1.5mol
0.5000 L
NaOH
Measure out 60 g of NaOH (s)
Add water to the 500.0 mL line
40.00 g
x
 60 g
1mol
23
• How would you prepare 500 mL of 3.0 M
NaOH from 12.0 M concentrated stock
solution?
(12.0 M)(X) = (3.0 M)(500 mL)
X=125 mL
Measure out 125 mL of
stock solution. Add it to 375
mL of distilled water
26
• An excess of zinc is added to 125 mL of
0.100 M HCl solution. What mass of zinc
chloride is formed?
Zn + 2HCl  ZnCl2 + H2
x
0.100M 
0.125L
```