Molarity

1
Chapter 8

• Molarity
• Part 1

2
Solutions

• Solute
• The substance that dissolves (the minor component
  of a solution).

KMnO4
3
Solutions

• Solvent
• The substance that the solute dissolves in (the
  major component of a solution).

4
Solution A homogeneous mixture of the solute
and solvent.
KMnO4 solution
5
Solutions
Dilute Concentrated
6
Concentration of a solution

• Molarity(M) is the moles of solute per liter of
  solution.

moles of solute
Molarity(M)
Liters of solution
7
Common Volume Units
1000 mL
8
Common Volume Units
1000 mL
9
Units of Molarity
10
Units of Molarity

• 2.0 M HCl

11
Units of Molarity

• 2.0 M HCl 2.0 moles HCl
• L solution

12
Units of Molarity

• 2.0 M HCl 2.0 moles HCl
• L solution
• 6.0 M HCl

13
Units of Molarity

• 2.0 M HCl 2.0 moles HCl
• L solution
• 6.0 M HCl 6.0 moles HCl
• dm3 solution

14
Molarity

• Calculate the molarity of an aqueous Ba(NO3)2
  solution containing 0.283 grams of barium nitrate
  in 0.931 L of solution.

15
Molarity

• Calculate the molarity of an aqueous Ba(NO3)2
  solution containing 0.283 grams of barium nitrate
  in 0.931 L of solution.

0.283 g Ba(NO3)2
0.931 L
16
Molarity

• Calculate the molarity of an aqueous Ba(NO3)2
  solution containing 0.283 grams of barium nitrate
  in 0.931 L of solution.

0.283 g Ba(NO3)2
mol
0.931 L
261.3 g
17
Molarity

• Calculate the molarity of an aqueous Ba(NO3)2
  solution containing 0.283 grams of barium nitrate
  in 0.931 L of solution.

0.283 g Ba(NO3)2
mol
0.00116 mol Ba(NO3)2/L 0.00116 M Ba(NO3)2
0.931 L
261.3 g
18
Molarity Calculation

• NaOH is used to open stopped sinks, to treat
• cellulose in the making of nylon, and to
• remove potato peels commercially.

19
If 4.0 g NaOH are used to make 500.0 mL of NaOH
solution, what is the molarity (M) of the
solution?
20
If 4.0 g NaOH are used to make 500.0 mL of NaOH
solution, what is the molarity (M) of the
solution?
4.0 g NaOH
500.0 mL
21
If 4.0 g NaOH are used to make 500.0 mL of NaOH
solution, what is the molarity (M) of the
solution?
4.0 g NaOH
mol
500.0 mL
40.0 g
22
If 4.0 g NaOH are used to make 500.0 mL of NaOH
solution, what is the molarity (M) of the
solution?
4.0 g NaOH
mol
mL
500.0 mL
40.0 g
0.001 L
23
If 4.0 g NaOH are used to make 500.0 mL of NaOH
solution, what is the molarity (M) of the
solution?
4.0 g NaOH
mol
mL
0.20 mol NaOH/L 0.20M NaOH
500.0 mL
40.0 g
0.001 L
24
Molarity Conversion Factors

• An NaOH solution has a molarity of 0.20M.
• Write this molarity in the form of conversion
  factors (ratios).

25
Molarity Conversion Factors

• 0.20 moles NaOH and L solution ____
• L solution 0.20 moles NaOH

26
How many grams of Na2SO4 are required to prepare
1000.0 mL of 1.0000 M Na2SO4 solution?
27
How many grams of Na2SO4 are required to prepare
1000.0 mL of 1.0000 M Na2SO4 solution?
1000.0 mL
28
How many grams of Na2SO4 are required to prepare
1000.0 mL of 1.0000 M Na2SO4 solution?
1000.0 mL 0.001 L
mL
29
How many grams of Na2SO4 are required to prepare
1000.0 mL of 1.0000 M Na2SO4 solution?
1000.0 mL 0.001 L 1.0000 mol Na2SO4
mL L
30
How many grams of Na2SO4 are required to prepare
1000.0 mL of 1.0000 M Na2SO4 solution?
1000.0 mL 0.001 L 1.0000 mol Na2SO4
142.04 g
mL L
mol
31
How many grams of Na2SO4 are required to prepare
1000.0 mL of 1.0000 M Na2SO4 solution?
1000.0 mL 0.001 L 1.0000 mol Na2SO4
142.04 g
mL L
mol
142.04 g Na2SO4
32
How to prepare 1000ml (1.000L) of a 1.0000M
solution of Na2SO4.
a
a
33
Diabetes is a serious medical issue facing our
country at this time.
34

• 23.6 million people in the United States (7.8 of
  the total population) have diabetes. Of these,
  5.7 million have undiagnosed diabetes.
• In 2007, about 1.6 million new cases of diabetes
  were diagnosed in people aged 20 years or older.
• If current trends continue, 1 in 3 Americans will
  develop diabetes sometime in their lifetime, and
  those with diabetes will lose, on average, 1015
  years of life.
• Diabetes is the leading cause of new cases of
  blindness, kidney failure, and nontraumatic
  lower-extremity amputations among adults.
• Diabetes was the sixth leading cause of death on
  U.S. death certificates in 2006. Overall, the
  risk for death among people with diabetes is
  about twice that of people without diabetes of
  similar age.
• In 19992000, 7 of U.S. adolescents aged 1219
  years had impaired fasting glucose (prediabetes),
  putting them at increased risk of developing type
  2 diabetes, heart disease, and stroke.

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Diabetes Is Preventable and Controllable

• Recent studies show that lifestyle changes can
  prevent or delay the onset of type 2 diabetes
  among people at high risk.
• For people with prediabetes, lifestyle changes,
  including a 57 weight loss and at least 150
  minutes of physical activity per week, can reduce
  the rate of onset of type 2 diabetes by 58.
• Disability and premature death are not inevitable
  consequences of diabetes. By working with their
  support network and health care providers, people
  with diabetes can prevent premature death and
  disability by controlling their blood glucose,
  blood pressure, and blood lipids and by receiving
  other preventive care in a timely manner.

36
Blood sugar is a term referring to the amount of
glucose (C6H12O6) present in the blood. A normal
blood glucose level is about 0.083g in 100.0mL.
What is the molarity of normal blood glucose?
0.0046M C6H12O6
37
In a college chemistry class you are asked to
prepare 100.0 mL solution of 0.250 M NiCl2 (gfm
129.7g/mol).
38
In a college chemistry class you are asked to
prepare 100.0 mL solution of 0.250 M NiCl2 (gfm
129.7g/mol).
How do you prepare the solution?
39
In a college chemistry class you are asked to
prepare 100.0 mL solution of 0.250 M NiCl2 (gfm
129.7g/mol). How do you prepare the solution.
3.24 grams of NiCl2
40
Dissolve 3.24 grams of NiCl2 in water then dilute
to a total volume of 100.0 mL.
41
Information for Mole Quiz

• How does a mole relate to particles and mass?
  (ie. One mole of H2O is 6.02 x 1023 H2O
  molecules and has a mass of 18.0 g).
• Be able to use the factor-label method to do
  metric conversions and mole problems.
• Know how to determine the number of atoms in a
  molecule. Be able to use this information in
  factor-label problems.
• Be able to determine the number of
  grams/molecule.
• Identify the diatomic gases.

42
Homework

• Molarity Worksheet. (Note that the answers to
  problem number 2 must be in sentence form).