Solution Chemistry Lab

Solution Chemistry Lab

Helpful Equations

Tb = kb x m Tf = kf x m kb water = 0.51 kf water = 1.86

m=moles of solute/kg solvent M = moles of solute /liters of water

M1V1 = M2V2 % Error = Predicted Value – Experimental Value x 100%

Predicted Value

Pre-Lab:

1.What are the units for molar mass?

a. g/mole b. g/mL c. mole/L d. L/mole

2. What is the molar mass of NaCl ______

3. What is the molar mass of CaCl2 ______

4. What is the molar mass of C12H22O11 ______

5. What are the units for molarity?

a. g/mole b. g/mL c. mol/L d. L/mol

6. If you multiply liters by molarity, what unit do you get?

a. Liters b. Grams c. Moles d. mL e. mol/L

7. Convert 30 mL into Liters ______

8. If you want to make a 2 M solution of NaCl in 30 mL of water, how many moles of NaCl would be required? ______

9. How many grams of NaCl would be required to make the 2M solution? ______

Calculate the amount (in grams) of each of the following compounds you would need to make a 1.5M solution in 150 mL of water.

10. A 1.5M solution of NaCl in 150 mL of water requires ______g of NaCl

11. A 1.5M solution of CaCl2 in 150 mL of water requires ______g of CaCl2

12. A 1.5M solution of C12H22O11 in 150 mL of water requires ______g of C12H22O11

13. What is the name of NaCl? ______

Is it an ionic compound or a covalent compound? ______

Is it soluble in water or is it insoluble in water?______

Will it conduct electricity when placed in water? ______

14. What is the name of CaCl2?______

Is it an ionic compound or a covalent compound? ______

Is it soluble in water or is it insoluble in water?______

Will it conduct electricity when placed in water? ______

15. What is the name of C12H22O11? ______

Is it an ionic compound or a covalent compound? ______

Is it soluble in water or is it insoluble in water?______

Will it conduct electricity when placed in water? ______

Solution Chemistry Lab

1. Get a Thermometer NEVER TOUCH THE THERMOMETER TO THE HOT PLATE!!!

2. Use the same thermometer in all three samples! Why?

3. Measure out the amount of each compound in grams (NaCl, CaCl2, and C12H22O11) you need - from the pre-lab - in a 250ml glass beaker. Use a pen to write the name of the compound on the beaker so you remember which one is which.

4. Put the thermometer into the beaker with NaCl. Add 150 ml of distilled water to the beaker.

What is the temperature the instant you added the 150 mL of water ______

Does the temperature go up or down or stay the same? If it goes up or down, what is the temperature it reaches ______WIPE OFF THE THERMOMETER and let it come back to room temperature before going on to the next one. Swirl the thermometer in the distilled water and that should bring it back to room temperature quickly.

5. Put the thermometer into the beaker with CaCl2. Add 150 ml of distilled water to the beaker.

What is the temperature the instant you added the 150 mL of water ______

6. Put the thermometer into the beaker with C12H22O11. Add 150 ml of distilled water to the beaker.

What is the temperature the instant you added the 150 mL of water ______

7. Put 150 mL of distilled water into a beaker - leave this beaker unlabeled. It will be pure water.

8. Put all FOUR beakers on the same hot plate (NaCl, CaCl2, C12H22O11 and pure water). Turn on the hot plate to about "7". Watch closely, because you are going to need to record the order in which they start to boil. In other words, I want you to tell me which one comes to a boil first, second, third, and fouth. Record in the data table below along with their boiling point

Solute / molality of solution (m) / Predicted Boiling Point Elevation (Tb) / Order it boiled (1st, 2nd, etc) / Predicted Boiling temperature / Experimental Boiling Temperature / Percent Error
Pure water
NaCl
CaCl2
C12H22O11

9. Predict the temperature of the boiling point of each of the solutions by calculating the molality and the Tb.

10. Which one of the solutions you used should have boiled at the highest temperature? Show your calculations to prove this:Show molality TbWorkbelow:

Calculations for Molaritywith Stock Solutions – Figure these out. Show Work Here:

Make 50 mL of a 0.4 M solution of salt water from 3.0M stock NaCl

______mL of stock solution

______mL of pure water you will add

(hint: The sum of the two amounts must equal 50 mL)

Make 50 mL of a 0.3 M solution of CaCl2from 3.0M stock CaCl2

______mL of stock solution

______mL of pure water you will add

(hint: The sum of the two amounts must equal 50 mL)

Make 40 mL of a 0.125 M solution AlCl3from 5.0M stock AlCl3

______mL of stock solution

______mL of pure water you will add

12. Which of the above stock solutions should boil at the highest temperature? You don’t need to test this, just show your work proving me you know how to do this.Show Work below:

Chapter 15 and your notes can be used to help answer these!

Heat Questions:

1. Which compound(s) got hot when added to water? (exothermic) Give their initial temperature (room temperature) and their hottest temperature.

2. Which compound(s) got cold when added to water? (endothermic) Give their initial temperature (room temperature) and their coldest temperature.

3. Which compound(s) remained the same temperature when they were added to water? (if none did, say: “none did”)

4. Look up at page 500, Table 16-4 in your textbook. What does it mean if: (answer both)

a. The heat of solution is a positive number ______

b. The heat of solution is a negative number ______

Molarity Questions:

5. True or False: "Molarity" is a form of "Concentration". (look in book or notes for help)

6. Each solution was made to be 1.5M. However, you made the solutions in 150 mL of water. How many moles of each compound were in each of the 150 mL samples? (Hint: If you made the solutions in 1L of water, then there would be 1 mole in each. If you made the solutions in 0.5 L of water, then there would be 0.5 moles in each…etc). Show work below

7. The compounds that were put into the water behaved differently. Some broke up into pieces, some didn't. NaCl, for instance, breaks up into two pieces: Na+1 and Cl-1. On the space provided below, tell me how many moles of particles were actually in each one of the 150 mL samples

NaCl ______CaCl2______C12H22O11 ______

Colligative Property Questions:

8. From your lab, which should have had solution had the highest boiling point?

9. What can you conclude about the effect on boiling point and the number of particles in solution? In other words, finish this statement: "the more the particles in solution, the ______the boiling point".

10. Look up the term: Colligative property in your textbook. What does it mean?

11. Is the boiling point of water affected by the colligative property? If so, how is it affected - does it go up or down with more particles? (Hint: Look at the answer you got to #7 and #9)

Electrolyte Questions:

12. What is the definition of an electrolyte? (You can look in your book or your notes)

13. True or False: A solution which contains electrolytes will conduct electricity. (look in book or notes)

14. Which of the solutions that you made contain electrolytes?

15. Which of the solutions that you made contain non-electrolytes?

16. True or False: covalent compounds do not form electrolytes.

17. True or False: ALL ionic compounds dissolve completely in water and form electrolytes.

18. True or False: SOME ionic compounds dissolve completely in water and form electrolytes.

19. True or False: Acids dissolve in water and form electrolytes. (check your book or notes!)

20. True or False: Some acids dissolve better than others in water. Therefore, some acids conduct electricity better than others in water. Strong acids dissolve better than weak acids.

What's due for the lab and in what order:

1. Pre-Lab.

2. Data table

3. Calculations when they are asked. Look in the procedure!

4. Questions – Just fill in the blanks

5. Solve for the % Error. (There is a space in on your data table and the equation for this is at the top page of the first page. You can show you work for this below this line. I have this listed at the end of the lab to see who actually reads this far down!)

You may write all of your answers on this lab. Please be sure to show any work NEATLY!