Names: __________________________________________________ Date: ____________ Period: ________
SOLUTIONS WEBQUEST
You can find a shortcut to all these links at:
STUCOMMONSOLOMAN DOCUMENTS CHEMISTRYSOLUTIONS WEBQUEST LINKS
The Dissolving Process
Go to: http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/molvie1.swf
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Look at the above animation. Explain how an ionic compound such as NaCl will dissolve in water. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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Does the sodium ion and chloride ion remain intact when dissolved? Draw a particle visualization of what NaCl looks like once it is dissolved in water (You don’t need to show the water, just the NaCl). Be sure to use two different colors for the sodium ion and chloride ion.
Go to: http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/thermochem/solutionSalt.html
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Look at the above animation. Explain why you do not see the salt particles after it is added to the water. Are the salt particles still present in the solution? Explain. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Factors Affecting Solubility
Go to: http://www.chem.lsu.edu/lucid/tutorials/solubility/Solubility.html
Read “Factors Affecting Solubility” in the above tutorial. Answer the following questions.
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Why does sugar dissolve faster in hot tea than in iced tea?
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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Why would granulated sugar dissolve faster in water than a sugar cube?
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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Why do we stir ice tea after we put sugar in it? Explain using the terms solvent, solute, and solution. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Factors Affecting the Rate of Solubility
Go to: http://www.thesciencedesk.com/pdffiles/FactorsAffectingDissolving.pdf
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What factors affect the solubility of a solid? How is it affected? ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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What factors affect the solubility of a gas? How is it affected?
________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Concentration and Molarity PhET-Chemistry Labs
Some handy vocabulary for you to define before you begin: Solute____________________________________________Solvent______________________________________
Moles _______________________________________________________________________________________
Molarity _____________________________________________________________________________________
Saturated (not fats) ____________________________________________________________________________
Unsaturated (not fats) __________________________________________________________________________
Supersaturated________________________________________________________________________________
Procedure: Click on StuCommon Soloman Documents Chemistry CONCENTRATION SIM
Part 1: Dissolution and Saturation
Take some time to play and familiarize yourself with the simulation. Click on everything. Move all the sliders. Notice what happens to the concentration as solid solute is added and when evaporation occurs.
1. How does the concentration change as solid solute is added? _________________________________
2. How does the concentration change as additional water is added? _____________________________
3. How does the concentration change as evaporation occurs? __________________________________
4. How do you know when a solution is saturated? ___________________________________________
5. When a solution is saturated, and additional solid solute is added, what happens? _______________
__________________________________________________________________________________________________________________________________________________________________________
Why do you think this is? __________________________________________________________
6. How does adding this additional solute change the concentration of this saturated solution? _____________________________________________________________________________________
7. How does evaporation change the concentration of a saturated solution? ___________________________________________________________________________________
Part 2: Concentrated Solutions
8. Adding a concentrated solution… describe a way to determine the concentration of the solution in the spigot. Write your plan here: __________________________________________________________________________________
_____________________________________________________________________________________
9. Using your plan…how might you get that concentrated solution to become saturated? ___________
____________________________________________________________________________________
Does your plan work for all the other solutions too? __________ Why? or Why Not? _______ __________________________________________________________________________________________________________________________________________________________________________
10. Create a saturated solution of cobalt chloride. Draw a particle visualization of what a saturated solution of cobalt chloride would look on a particle level in side the container. Be sure to show the container and use two different shapes or two different colors to show the different particles.
b. Now, in the program, add more cobalt chloride to the solution. What happened? Draw a particle visualization of what the solution looks like after you’ve added more solution. Did the concentration change? ____________ What did change?_________________________________________________________________
_____________________________________________________________________________________________
Part 3: Molarity StuCommon Soloman Documents Chemistry MOLARITY SIM
Molarity is moles per Liter, that is, how many moles of solute (entire salt) is dissolved per Liter of solution.
Click the box that says “Show Values.”
First, determine the saturation concentration of each of the solutions, that is, how concentrated can you get each solution before the solution is saturated. If you can’t determine the saturated concentration using the simulation “Molarity” (and some of them you won’t), try using the simulation “Concentration.” (You will use this information again in Part 5.)
Part 4: Calculating Molarity Using the simulation and the formula for Molarity above, complete the table below.
Moles of Compound (mol)
|
Liters of Solution (L)
|
Molarity of Solution (M)
|
Moles of Compound (mol)
|
Liters of Solution (L)
|
Molarity of Solution (M)
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.53
|
.79
|
|
|
.78
|
.59
|
.86
|
.34
|
|
.88
|
|
1.8
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1.0
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.20
|
|
3.5
|
8.4
|
|
.67
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.67
|
|
|
6.4
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8.5
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Part 5: (Extension Exercise) Total Ion Concentration
Just as an entire solution has a concentration, so does each individual ion. For instance, since there are three ions when a Calcium Chloride CaCl2 molecule dissolves into solution, a 3.0 M solution of CaCl2 is 3.0 M with respect to Ca2+ ions and 6.0 M with respect to Cl- ions, for an overall ion concentration (solubility) of 9.0 M (3.0 M + 6.0 M).
Using what you know about inorganic nomenclature and common ions, complete the table below
Compound
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Saturated Concentration (from Part 3)
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Cation Molarity
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Anion Molarity
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Total Ion Solubility
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Co(NO3)2
|
|
|
|
|
CoCl2
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|
|
|
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K2Cr2O7
|
|
|
|
|
AuCl3
|
|
|
|
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K2CrO4
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|
|
|
|
NiCl2
|
|
|
|
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CuSO4
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|
|
|
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KMnO4
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|
|
|
|
Conclusion Questions and Calculations, Concentration and Molarity Post-Lab Exercises
“Concentration” or “Molarity”
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Adding pure water to a saturated solution (with no solids) would cause the concentration of that solution to increase / decrease / remain the same. (circle)
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Adding pure water to a saturated solution (with some solids) would cause the concentration of that solution to initially increase / decrease / remain the same. (circle)
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Adding a solid salt to a saturated solution causes the concentration of that solution to increase / decrease / remain the same.
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Evaporation acting on an unsaturated solution causes the solution’s concentration to increase / decrease / remain the same.
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Evaporation acting on a saturated solution causes the solution’s concentration to increase / decrease / remain the same.
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Can you dissolve .35 moles of Potassium Permanganate (KMnO4) into 0.500 L of water? _________ Why? / Why not? (please show work) (Hint: You will have to compare its saturation concentration to your answer.)
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What is the molarity when 2.8 moles of NaCl is dissolved to make a solution with a total volume of 1.3 L? (please show work)
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What is the solution concentration when 2.1 moles BaCl2 is dissolved to make a solution with a total volume of 1.9 L? (please show work)
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How many moles of solute are present in .75 L of a .89 M (molar) solution? (please show work)
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How many grams of solute are present in 1.4 L of a 1.9 M (molar) solution? (please show work)
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