Unit 1C Reading Guide

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 à Na+ + Cl-

______

C.5 Modeling Matter: The Dissolving Process

1.a. What changes would you see in the beaker? ______

______

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 à + 100g H2O

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 2. What is the % NaCl of this solution?

495 g HbO how much solution is produced?

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? ______

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 )

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!