Unit 1C Reading Guide
Investigating the Cause of the Fish Kill
C.1 Solubility of Solids in Water
1. What does "solubility" mean? _____________________________________________________________
_____________________________________________________________________________________
2. How is solubility measured (units)? ________________________________________________________
3. Describe "solute solubility curve". _________________________________________________________
_______________________________________________________________________________________
4. The substance that dissolves in a solution is the_______________________________________________
5. The substance that does the dissolving in a solution is the _______________________________________
Use the graph to answer these questions.
6. This graph shows the solubility of three salts. Name them.
________________________________________________
7. What does the Y axis show? _________________________
________________________________________________
8. What does the X axis show? _________________________
9. At any point on the line showing solubility of KCl the solution is:
A. supersaturated
B. unsaturated
C. saturated
10. Look at potassium nitrate. What happens to the amount of
salt in solution as the temperature rises? ___________________
11. A solution with as much dissolved solute as can normally be held is a ____________________________
solution.
12. If a solution has more solute than it normally holds (*and is still dissolved) the solution
is _____________________________.
13. A solution that can hold more solute is _______________________________________.
C.2 Developing Skills: Solubility and Solubility Curves
Hint: You must use the graph to answer the questions. Read carefully!!
1. (Hint: Read the graph)
a. Mass KNO3 in grams = _______________
b. Mass KC1 = ______________
2. (Hint: Where do you start? Read the graph! Show your work!)
a. ________________________________________________________________________________
b. ___________
(Work space)
3. a __________________________________
(work space)
b. ________________________________
(work space)
C.3 Investigating Matter: Constructing a Solubility Curve
1. What is the formula for succinic acid? _________________________________
2. What three questions should you think about before continuing with this lab?
1. __________________________________________________________________________
2. ___________________________________________________________________________
3. __________________________________________________________________________
4. READ the safety precautions several times.
Procedure
1. In this lab ________________________ will be the solute and _______________________ the solvent.
2. Think about this. A farmer puts a water soluble chemical on his field. What (in the natural environment
will determine if it dissolves? What will determine if it becomes a saturated, unsaturated or supersaturated
solution?
3. Why use a warm water bath? _____________________________________________________________
4. Predict what will happen to the solubility of succinic acid as the temperature increases. ______________
______________________________________________________________________________________
5. What is the highest temperature a water bath will be heated to? ________________________________
6. How much succinic acid will be placed into the test tube? _____________________________________
7. How long are the liquids that have been decanted placed in the ice bath? __________________________
8. What does "decant" mean? _______________________________________________________________
9. What does the height of the crystals represent? _______________________________________________
C.4 Dissolving Ionic Compounds
1. Water is a polar molecule. What does this mean? _____________________________________________
_______________________________________________________________________________________
2. What is the shape of a water molecule? _____________________________________________________
3. What is the total charge of a water molecule? _______ How is the charge distributed? Use the
diagram at the right to help explain the charge distribution.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
4. Dissolving has been compared to a “tugging of molecules.” Explain. ____________________________
____________________________________________________________________________________
Draw a sketch of polar water dissolving ionic NaCl. Explain your sketch.
NaCl  Na+ + Cl-
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
C.5 Modeling Matter: The Dissolving Process
1.a. What changes would you see in the beaker? ___________
__________________________________________________
b.
50C
_________________________
40C
25C
__________________________
_________________________
S = saturated
U = unsaturated
P = supersaturated
2.a. 20 g KCl in 100 g H2O (40C)
¼ H2O evaporated
ii. How much water must evaporated at 40C to create a saturated solution?
3. What does “diluted” mean? ___________________________________________________________
a. 10.0 g KCl / 100g H2O at 25C H2O
 + 100g H2O
a.
b.
c. Compare key features of the models above
_______________________________________________________________________________________
_______________________________________________________________________________________
C.6 Solution Concentration
1. Define solution concentration- ___________________________________________________________
_____________________________________________________________________________________
2. "Percent" means ______________________________________________________________________
3. A solution of salt and water contains 15 grams of salt and 85 g of water. The solution is ________ % salt.
4. Another way to describe the solution in #3 is __________ parts per hundred.
5. Express the example above into parts per million. (*See Sample Problem page-63)
6. Write 0.0025% as parts per billion. ____________________ ppb
C.7 Describing Solution Concentration (Show all work)
1. If a sterile solution requires 4.5 g NaCl and
495 g HbO how much solution is produced?
_____________ g solution
2. What is the % NaCl of this solution?
C.8 Inappropriate Heavy-Metal Ion concentration in River?
1. Compare heavy-metal ions with essential metal ions. __________________________________________
_____________________________________________________________________________________
2. This section describes bioaccumulation/ biological magnification. What happens to organisms higher up
in the food chain during this process? How/why? _____________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
3. Why are heavy-metal ions harmful? _______________________________________________________
______________________________________________________________________________________
4. What is the best way to prevent heavy-metal poisoning? _______________________________________
_______________________________________________________________________________________
5. How did the heavy metal "lead" get its symbol? ______________________________________________
6. Identify some sources of lead (Pb 2+) in our environment. ______________________________________
_______________________________________________________________________________________
7. Why was lead added to gasoline? __________________________________________________________
8. What is unusual about metallic mercury (Hg2+) ? ____________________________________________
9. Identify beneficial uses of mercury. ________________________________________________________
10. What are symptoms of mercury poisoning? _________________________________________________
11. Identify any sources of mercury along the Snake River that could be responsible for the fish kill.
________________________________________________________________________________
C. 9 Inappropriate pH Levels in River?
1. Define pH scale- _______________________________________________________________________
2. Solutions with pH lower than 7 are ____________ Solutions with pH higher than 7 are ____________
3. Another name for a basic solution is ______________________________
4. When moving up or down the pH scale a change from one number to the next indicates a ____ difference.
A solution with a pH of 2 is ________ times more acidic than a pH of 4
5. A basic solution turns litmus __________ and an acid solution turns litmus ___________
6. Are acid and base solutions conductors? ____________________________
7. Acids and bases are corrosive. Define corrosion (hint: look in the glossary!)-_______________________
_____________________________________________________________________________________
_____________________________________________________________________________________
8. Acids release ___________________ in water. Bases release _________ ions in water.
9. Substances that display neither acidic or basic properties are ________________________
10. At _____°C a pH of ________ indicates a neutral substance.
11. How is a low pH harmful to organisms living in a stream or lake ? _______________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
12. How is a high pH harmful to organisms living in a stream or lake ?______________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
13. According to the EPA, what must the pH range for drinking water be ? ________________________
14. Identify the pH range that most fish can survive. ____________________________________________
15. What is the normal pH of the Snake River ? ______________________________
C.10 Inappropriate Molecular-Substance Concentrations in River?
1. When ionic substances (like NaCl) dissolve in water they release __________.
2. Substances that dissolve in water but do not release ions, rather they release molecules are called
______________________ substances. Examples are _________________________________
3. Oxygen and carbon dioxide are examples of molecular substances that could dissolve in water. They are
gases at room temperature. Why are they gases at room temperature? ___________________________
___________________________________________________________________________________
4. Molecules that may be liquids at room temperature are _______________________________________
These substances have larger between molecule attraction which causes them to be __________________
than gas molecules.
5. Some substances like succinic acid are solids at normal temperatures. Why? ________________________
_____________________________________________________________________________________
6. What determines how soluble a molecular substance will be in water? _____________________________
_______________________________________________________________________________________
7. What causes the attractions mentioned in #6? ________________________________________________
8. Explain electronegativity as it relates to an atoms attraction of electrons. __________________________
_______________________________________________________________________________________
9. There is an old saying "likes dissolve likes", in chemical terms, explain it. _________________________
_______________________________________________________________________________________
C. 11 Laboratory Activity. Solvents
Introduction
1. What is the purpose of this lab, and how will the data you produce during the lab help you in relation to
the problem being investigated in Riverwood?_______________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
2. Who will prepare the laboratory procedure for this lab?_________________________________________
3. For the purpose of this lab, how will you determine if something is insoluble?_______________________
_______________________________________________________________________________________
4. What solvents will you test in this lab?______________________________________________________
5. What solvent will you use that is polar?_____________________________________________________
6. What solvent will you use that is nonpolar?__________________________________________________
7. How will you rate the solubility of the solutes?________________________________________________
C.12 Inappropriate Dissolved Oxygen Levels in River?
1. What is the solubility of oxygen gas in 10°C water? __________ mg O2 / 1000 g H2O
2. What is the solubility of oxygen gas in 30°C water? __________ mg O2 / 1000 g H2O
3. Consider temperature and compare the solubility of a gas with a solid._____________________________
_______________________________________________________________________________________
4. How does pressure affect gas solubility? ________________
_______________________
5. What is the metric unit for
pressure? _____________
Temperature (C)
C.13 Temperature Dissolved Oxygen and Life
1. Explain what cold blooded means. _________________________________________________________
2. Fish are cold-blooded. What happens to a fish on a warm summer day?____________________________
_____________________________________________________________________________________
3. Why do we have fish kills in the summer? ___________________________________________________
_______________________________________________________________________________________
4. There are at least 2 common human activities that are known to raise water temperature. Give 2 examples
of these activities, and name the type of pollution they are classified as (hint: think back to environmental
science!) ____________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
5. Look at Figure 1.51 (page 77) Which fish have the highest dissolved oxygen demand in the winter?
___________ Which have the highest dissolved oxygen demand in the summer?____________________
6. Diagram a sample of water from a river. Label the water
molecules and the dissolved oxygen molecules.
(* Hint: use models )
KEY
Dissolved O2=
Water =
7. Can fish die from too much oxygen in the water? Explain______________________________________
_______________________________________________________________________________________
C.14 Making Decision: Determining the Cause of the Fish Kill
Data Analysis
• Be sure to read the directions carefully.
• Review graphing procedures if you need to
• Search for patterns in the data
Quiz
Unit 1C Reading Guide
Investigating the Cause of the Fish Kill
You may use your study guide to answer these questions. No photo copies may be used.
_____ 1. The substance that dissolves in a solution is the ___
A. saturated
B. solute
C. solvent
_____ 2. What is the formula for succinic acid? (Write the formula on the answer blank)
_____ 3. What is a solution that can hold more dissolved solids.
A. saturated
B. unsaturated
C. supersaturated
_____ 4. A molecule with a total charge of 0, but with an uneven distribution of charge is
A. saturated B. ionic C. dilute
D. polar
_____ 5. In the lab "Constructing a Solubility Curve" why was a warm water bath used?
A. to purify the distilled water
B. to cause the solids to precipitate
C. to speed up the dissolving of the solids
D. to supersaturate the solvent
_____ 6. In the lab, you were asked to "decant”. What did this mean?
A. measure the crystals carefully with a metric ruler
B. tap the sides of the test tube
C. pour the liquid carefully
D. heat the solution
_____ 7. Express a solution having 35 grams of NaCl per 100 grams of solution in terms of pph.
_____ 8. What is an unusual property of mercury?
A. it is a liquid at room temperature
B. it has a very high boiling point
C. it has a very low boiling point
D. it is quick silver
_____ 9. Which is NOT a source of lead poisoning?
A. paint chips in older houses
B. electrical storage batteries
C. certain potteries and pesticides
D. gasoline
_____ 10. Another name for an alkaline solution is
A. caustic
B. toxic
C. acid D. base
_____ 11. A solution with a pH of 3 is a/an
A. acid
B. base C. neutral
_____ 12. Hydroxide ions are released by ___ in water.
A. polar substances
B. neutral substances
C. acids
D. bases
_____ 13. What damage can a low water pH cause to the living organisms in a river?
A. damages skin and scales by dissolving them
B. damages fish eggs
C. raises water temperature
D. cause increase carbon dioxide levels
14. Compare polar molecules with ionic compounds.
Bonus
1. A word meaning decay or deteriorate is __________________________________
2. The EPA suggests the pH for drinking water should be _______________________________
3. What is the pH of the Snake River? _________________________________________________
4. A solution is composed of 30 grams of NaCl and 170 mL of H2O. What is the solution
concentration? Show your work!