BSC1005L

 Laboratory sample
This is a sample of one of the online laboratories. It will actually be done within WEBCT software so the page layout will be different but the text will be similar. Each of the numbered  parts (e.g., part 1, part 2) requires a response by the student: in the space provided by the WEBCT software; at a data input web page or on a bulletin board posting.

Solutions and pH Laboratory

Readings

Read the textbook chapter and chapter narrative.
 

Materials Needed

pH paper,cups
water
oil
baking soda, orange or lemon juice
salt, sugar, corn starch
 

General Laboratory Question

What molecules are soluble in water; which are not? What is a solute? What is the pH of common household
solutions? And what is the relationship of the pH value to hydrogen ions?
 

Solutions activity procedure (part 1)

For this demonstration, you will look at the solubility of chemicals like an organic acid (orange juice), a pH buffer (baking soda), a complex carbohydrate (corn starch), an electrolyte (table salt), a lipid (cooking oil)  and a simple carbohydrate (table sugar)  in water.
 Add each of the six (6)  substances to water to make a solution then answer the following questions in the space below.
a)For each of these six solutions, name the chemical that is the solvent and name the chemical that is the solute?
b)For each of these six solutions describe if it was soluble in water.
c) IF these chemical solutions represent ordinary solutions found in cells(and they do!), THEN predict what the most common solvent is found in life?
 

Solutions activity results (part 2)

 Note: Chemicals that dissolve in (are soluble in) water can be transported by water.

Answer the following questions
1a) IF a cell membrane is made out of an oil-based chemical( and it is!), THEN predict, in the space below,  whether water soluble chemicals can pass through the oily membrane to go into or out of the cell. Explain which results of the demonstration support this prediction.

2. Place oil in an empty cup. Then add some more oil to the oil. Answer the following questions.
a) Is oil soluble in oil?
b) IF a cell membrane is made out of oil-based chemicals, THEN predict if an oil based chemical can pass through the  cell membrane.
 

pH experiment (part 3)

For this second topic, you will perform a demonstration in which you will measure the amount of hydrogen ions (pH) in the solutions.
1. Take a  pH paper and place in the each of the previously produced water-based solutions (not the oil-oil solution) for 1-2 seconds.
2. COMPARE the color of the strip with the colors on the pH scale within 30 seconds and  RECORD the pH value for each of the  solutions.
3. PRODUCE a table of the data and submit it below. In the table, label each solution as "acid" or "base"
4.Click here to <a href ="http://it.spcollege.edu/cfpro/alans/bsc1005lstu/lab2/index.cfm">REPORT your solutions and their pH values so all laboratory participants can observe your data.</a>
5. Draw a bar graph of the data that you gathered (see figure 5.3A for example).  Use  "pH scale" for the vertical  axis title (use values from 1 at bottom to 14 at top) and print  names of the fluids on each bar.  Neatness is important!
6. Print, Sign and FAX the graph to the instructor.
7. In the  below space, STATE the relationship between numbers of hydrogen ions in solution and the pH value of the solution.
8. Answer the discusion question in the bulletin board.