HONORS CHEMISTRY 1

Name: ________________________

Mods: ________________________

Chemistry Work - Solutions

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Name ___________________________________________ Date ______________

1. What is the solubility of sodium nitrate at 45oC?

2. What is the solubility of salt at 20oC?

3. How many grams of potassium nitrate can you dissolve in 100 cm3 of water at

50oC?

4. How many grams of potassium chlorate can you dissolve in 100 cm3 of water at

100oC?

5. At what temp are the solubilities of sodium chloride and potassium nitrate the

same?

6. At what temp are the solubilities of sodium chloride and sodium nitrate the same?

7. How much sodium nitrate can you dissolve in 40 cm3 of water at 100oC?

8. How much salt can you dissolve in 20 cm3 of water at 60oC?

9. If 100. cm3 of a saturated solution of sodium nitrate is cooled from 70.0Cto room

temp (20.0C), How much sodium nitrate precipitate will form at the bottom of the

solution?

10. If a 50.cm3 of a saturated solution of potassium nitrate at 150C is heated to 500C,

how much more potassium nitrate can dissolve.

HONORS CHEMISTRY 8

Name:______________________________ Date:_______________

Mole Houses!

The moles of room 335 are in a huge fight. They are arguing about who is living in the

most crowded conditions. Of course, the most crowded moles will have the highest

molarity. Help the moles solve their dilemma.

HOUSE 1 M = ----------------- = HOUSE 2 M = ------------------- =

HOUSE 3 M = ---------------- = HOUSE 4 M = ------------------ =

HOUSE 5 M = ----------------= HOUSE 6 M = ------------------ =

HOUSE 7 M = ----------------= HOUSE 8 M = ------------------ =

HOUSE 9 M = ----------------= HOUSE 10 M = ----------------- =

Which moles have the most crowded living conditions?? ____________________

Solve the following problems.

1. 4.5 grams of NaOH is dissolved in 3.5 L of solution.

2. 56.7 grams of NaCl is dissolved in 2.1 L of solution.

HONORS CHEMISTRY 9

Name:___________________________ Date:___________

Molarity

1. How do you make 3.5 L of a 4.5 M solution of Mg(OH)2.

2. How do you make 2.1 L of a .75 M solution of Al(NO3)3.

3. How do you make .35 L of a 1.5 M solution of BaCl2.

4. 3.4 g of NaCl is dissolved in 500 mL of water. What is the molarity?

5. 7.6 g of NaOH is dissolved in 350 mL of water. What is the molarity?

HONORS CHEMISTRY 10

Name _________________________ Molarity Lab

Calculate how many grams of NaCl you will need to add to water in order to make solutions of the given molarities.

Solution #1: 0.25 M solution in a 2000 ml flask. Solution #2: 0.50 M solution in a 500 ml flask. Solution #3: 0.75 M solution in a 1000 ml flask. Solution #4: 1.00 M solution in a 250 ml flask. Solution #5: 1.25 M solution in a 25 ml flask.

Solution #6: 1.50 M solution in a 10 ml flask.

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Solution #7: 1.75 M solution in a 100 ml flask. Solution #8: 2.00 M solution in a 50 ml flask. Solution #9: 2.25 M solution in a 100 ml flask. Solution #10: 0.25 M solution in a 25 ml flask. Solution #11: 1.25 M solution in a 100 ml flask. Solution #12: 2.25 M solution in a 25 ml flask.

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Name:______________________________ Date:_______________

Colligative Properties Practice

FOR WATER Kf = 1.86 oCkg/mol Kb = .51 oCkg/mol

1. Consider the following solutions:

0.010 m Na3PO4 in water

0.020 m CaBr2 in water

0.020 m KCl in water

0.020 m HF in water (HF does not dissociate much b/c it is a weak acid)

A. Highest freezing point

B. lowest freezing point

C. Highest boiling point

D. Lowest boiling point

2. From the following:

Pure water

Solution of C12H22O11 (m =0.01) in water

Solution of NaCl (m = 0.01) in water

Solution of CaCl2 (m = 0.01) in water

Choose the one with the

A. Highest freezing point

B. lowest freezing point

C. Highest boiling point

D. Lowest boiling point

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3. Calculate the freezing point and boiling point of each of the following solutions

using the observed van’t Hoft factor.

A. 0.050 m MgCl2

B. 0.050 m FeCl3

4. Calculate the freezing point and boiling point of an antifreeze solution that is 50.0

g ethylene glycol (HOCH2CH2OH) in 50.0 g water. Ethylene glycol is a

nonelectrolyte.

5. What mass of glycerine (C3H8O3), a nonelectrolyte, must be dissolved in 200.0 g

water to give a solution with a freezing point of -1.50oC?

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Name:________________________ Date:__________________

The molecular weight and formula of a hydrocarbon are to be determined through the

use of the freezing point depression method. The hydrocarbon is known to be 86%

carbon and 14% hydrogen by mass. In the experiment, 3.72 grams of the unknown

hydrocarbon were placed into 50.0 grams of liquid benzene, C6H6. The freezing point

of the solution was measured to be 0.06oC. The normal freezing point of benzene is

5.50oC and the freezing point depression constant for benzene is 5.12 oC/m.

A. What is the empirical formula for the hydrocarbon? Calculate the molar mass for

this empirical formula.

B. Calculate the freezing point depression

C. Calculate the molality of the solution

D. Calculate the moles of hydrocarbon added to the benzene

E. Calculate the molar mass (g/mole) of the hydrocarbon

F. What is the molecular formula for the hydrocarbon

HONORS CHEMISTRY 19

Name:_______________________ Date:____________

A. The molecular weight and formula of a hydrocarbon are to be determined through

the use of the freezing point depression method. The hydrocarbon is known to be

85.7% carbon and 14.3% hydrogen by mass. The hydrocarbon dissolves readily in

CCl4. A solution prepared by mixing 135 grams of CCl4 and 4.36 grams of the

hydrocarbon has a boiling point of 78.7oC. The molal boiling point elevation

constant of CCl4 is 5.02 oC/molal, and its normal boiling point is 76.8oC.

Calculate the molecular weight of the hydrocarbon.

A. What is the empirical formula for the hydrocarbon? Calculate the molar mass for

this empirical formula.

B. Calculate the boiling point elevation

C. Calculate the molaltiy of the solution

D. Calculate the moles of hydrocarbon added to the benzene

E. Calculate the molar mass (g/mole) of the hydrocarbon

F. What is the molecular formula for the hydrocarbon

HONORS CHEMISTRY 20

Name ________________________________________ Date _________________

REVIEW

SOLUBILITY

1. ____________________ is the substance that is dissolved.

2. ____________________ is the substance that does the dissolving.

3. ____________________ is a homogeneous solution.

4. A ____________________ solution has the maximum amount of solute dissolved

in a given amount of solvent.

5. A ___________________ solution can dissolve more solute.

6. Opposite of soluble is ___________________.

7. _________________ is how many grams of solute dissolves in 100 cm3 of water.

8. For most solid solutes, as temperature goes up, solubility goes _______________

9. For most gas solutes, as temperature goes up solubility goes _________________

10. Discuss thermal pollution and its affects on gas solubility:

11. What is the solubility of NaCl at 25oC?

12. What is the solubility of KNO3 at 70oC?

13. At what temperature is the solubility of KNO3 20g/100cm3 H2O?

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14. At what temperature is the solubility of NaNO3 90g/100cm3 H2O?

15. How many grams of KClO3 dissolves in 100 cm3 H2O at 30oC?

16. How many grams of KNO3 dissolves in 100 cm3 H2O at 50oC?

17. How many grams of KCl will dissolve in 40 cm3 H2O at 80oC?

18. How many grams of NH3 will dissolve in 500 cm3 H2O at 80oC?

19. How many grams of KNO3 will dissolve in 250 cm3 H2O at 50oC?

20. If 30 grams of KNO3 are dissolved in 100cm3 H2O at 20oC, will the solution be

saturated or unsaturated? Explain why?

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REVIEW

MOLARITY, MOLALITY, MASS PERCENT

21. How many moles of Na3PO4 are needed to make 500.0 ml of a 0.50 M solution?

22. What is the molarity of a solution containing 10.00 g of H3PO4 dissolved in 500.0

ml of solution?

23. How many grams of calcium oxide are needed to make 50.0 ml of a 0.75 M

solution?

24. How many liters of solution are needed to dissolve 25.5 g hydrogen phosphate if a

concentration of 0.25 M is needed?

25. What is the nitrate ion concentration if 22.50 g of barium nitrate are dissolved in

500. ml of solution?

26. How many grams of H2SO4 were dissolved in 250.0 ml of solution if the final

hydrogen ion concentration is 0.25 M?

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27. Calculate the molality of a solution of 50.0 g nickel (II) chloride in 100.0 g of

water.

28. 12.5 g barium chloride dissolves in 250. ml of water. Calculate the mass percent

concentration.

29. What is the new boiling point is 25.0 g of calcium chloride is dissolved in 500. ml

of water?

30. When 10.0 g of a nonelectrolyte is added to 50.0 g of water, the new freezing

point is -3.25oC. What is the molecular mass of the unknown compound?

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Lab Freezing Point Depression

Procedure:

1) Mass out 5.00 g of naphthalene and place it in a test tube

2) Place test tube containing naphthalene in a beaker of water and heat until all the

solid has melted

3) Remove the test tube from the water bath and begin recording the temperature

using data studio on the computer (remember to continuously stir the liquid in the

test tube)

4) Continue to record the temperature until all the liquid has frozen

5) Place the test tube back in the water bath and re-melt the solid

6) Mass out 0.500 g of unknown and add it to the liquid in the test tube

7) Repeat steps 3-5 above

8) Remove and clean the thermometer

9) Place the test tube (with contents) in the beaker in the fume hood

10) Calculate the freezing point depression

11) Calculate the molar mass of the unknown solid

Data:

Mass of naphthalene (solvent)

Mass of unknown (solute)

Freezing point for pure naphthalene

Freezing point for naphthalene and unknown solute

Calculations:

1) Freezing point depression

2) molality of solution

3) moles of solute

4) molar mass of solute