1. Launch: 1/12
 Grab your binder and immediately take a seat!
 Place launch paper and HW (practice questions) on your
desk.
 Yesterday’s Exit Slip Data:
N/A
 Today’s Objective: I can calculate the concentration of a
solution in terms of molarity.

2. Launch: 1/12
 Grab your binder and immediately take a seat!
 Place launch paper and HW (practice questions) on your
desk.
 Yesterday’s Exit Slip Data:
N/A
 Today’s Objective: I can calculate the concentration of a
solution in terms of molarity.

3. Launch: 1/12
 Grab your binder and immediately take a seat!
 Place launch paper and HW (practice questions) on your
desk.
 Yesterday’s Exit Slip Data:
N/A
 Today’s Objective: I can calculate the concentration of a
solution in terms of molarity.

4. Launch: 1/12
 Grab your binder and immediately take a seat!
 Place launch paper and HW (practice questions) on your
desk.
 Yesterday’s Exit Slip Data:
N/A
 Today’s Objective: I can calculate the concentration of a
solution in terms of molarity.

5. Launch 1/12
1. In 1-2 sentences, explain what you did in lab on
Friday.
• What variable did you change?
• What were the results of your experiment?

6. Launch 1/11
2. 5 grams of sugar would dissolve the fastest in
a. cold water.
b. warm water.
c. hot water.
d. none of the above.

7. Launch 1/11
4. Which of the following would dissolve the fastest in
water?
a. powdered sugar (most surface area)
b. granulated sugar (moderate amount of surface area)
c. broken sugar cubes (moderate amount of surface area)
d. sugar cubes (least amount of surface area)

8. Announcements
 Late homework policy
 Late homework in now due the day after you return
 Quiz on Friday!

9. January Calendar

10. What is concentration? –
Part II
Mr. Heffner
1/11/10

11. Review: What is concentration?
 Concentration is…
 the amount of solute dissolved a in solution.
 Concentration is measured in…
 grams per liter (g/L)

12. What is concentration?
 Concentration is also measured in…
 Molarity = moles per liter (mol/L) = M volume
 the # of moles of solute in one liter of solvent
 A mole is… # of
moles
 a unit of measurement (6.02 X 1023 atoms)

13. Examples
1. If 2 moles of NaCl are dissolved in 1L of H2O, what is the
molarity of the solution in mol/L?
“two molar”
2 mol
1L = 2 mol/L = 2 M
In every 1L of solution,
there are 2 moles of NaCl

14. Examples
2. If 3 moles of NaCl are dissolved in 6L of H2O, what is the
molarity of the solution in mol/L?
“point-five
molar”
3 mol
6L =.5 mol/L = .5 M
In every 1L of solution,
there are .5 moles of NaCl

15. Examples
3. How many moles of NaOH are needed to prepare 2.0 L of
a 2 M solution?
2 M = 2 mol/L
2 mol 2 X 2 mol
2L x = = 4 mol
1L 1

16. Examples
3. How many moles of HNO3 are needed to prepare 4 liters
of a 6 M solution?
6 M = 6 mol/L
6 mol 4 X 6 mol
4L x = = 24 mol
1L 1

17. Whiteboards
 Work in pairs
 Trade-off marker every question
 Partner without the marker should be checking
work at each step!
 You have 60 seconds to solve the question
 Show all of your work!
 Don’t forget units!
 Lift board only when prompted

18. If 3 moles of Na2CO3 is
dissolved in 1L of H2O,
what is the molarity of the
solution in mol/L?

19. What is the molarity of the
solution if 3 moles of KBr is
dissolved in 6 liters of H2O?

20. How many moles of HCl are
needed to make 10 liters of
a 4 M solution?

21. How many moles of KOH are
needed to make .5 liters of
a 2 M solution?

22. Practice Questions
 Practice question worksheet

23. Exit Slip
1. Concentration is
a. how well a solute dissolves in a given amount of solvent.
b. when two substances are not evenly mixed throughout.
c. a measure of the amount of solute dissolved in a
solution.
d. reported in units of cm/L.

24. Exit Slip
2. Concentration is calculated by
a. dividing the mass of the solute by the volume of the
solvent.
b. summing the masses of all the parts in a solution.
c. multiplying the masses of the solute and solvent.
d. multiplying the volume of the solute by the mass of the
solvent.

25. Exit Slip
3. If 60g of NaCl is dissolved in 20L of H2O, what is
the concentration of the solution in g/L?
a. 2g/L
b. 3g/L
c. 6g/L
d. 120g/L

26. Exit Slip
4. How many grams of salt are there in a .5L solution
of sugar water that has a concentration of 10g/L?
a. 2g
b. 5g
c. 20g
d. 50g

27. Exit Slip
5. If the solubility of C6H12O6 (sugar) is 40g/100L,
what mass of sugar can be dissolved in 50L of
water?
a. .4g
b. .4g/L
c. 20g
d. 400g/L

28. Homework
 Finish practice questions