PH of Biological Substances Laboratory



Names: ______________________________ ______________________________

Directions:

• Label a blank sheet of notebook paper as diagrammed on the board. Divide the paper into 8 equal squares and label them 1) lemon juice, 2) lemon juice & tums, 3) water, 4) baking soda solution, 5) ginger ale, 6) glass cleaner, 7) mustard, 8) discarded pH strips.

• Use a small pH strip to test each substance. Dip the pH strip half-way into your solution, pull it out and dab off any excess liquid. Place the pH strip on your scratch paper and wait about 30 seconds. Use the back of the pH tubes to estimate the substance’s pH. DO NOT touch the tube or you may blur the pH color guide (and cause your results to be inaccurate)!

Lemon Juice

1) What is the approximate pH of lemon Juice ___________

2) Why do you think that lemon juice does not burn through your throat or skin?

_____________________________________________________________________

Lemon Juice & Tums

3) What is the approximate pH of the lemon juice & Tums solution ___________

4) What would be the approximate pH of Tums ___________

(base your answers on the results you got in # 1 & # 3)

5) Tums is an “anti-acid.” What does this tell us about how Tums would react with your

stomach acid when you have “heart burn?”

_____________________________________________________________________

Water

6) What is the approximate pH of water? ___________

7) Why do you think it is important that water has a relatively neutral pH?

_____________________________________________________________________

Baking Soda Solution

8) What is the approximate pH of baking soda? ___________

Ginger Ale

9) What is the approximate pH of ginger ale (soda)? ___________

10) Hypothesize what (or why) you think might cause the soda to have this pH.

(Look at the ingredients on the soda bottle.)

____________________________________________________________________

Glass Cleaner

11) What is the approximate pH of glass cleaner (NH4OH)? ___________

Mustard

12) What is the approximate pH of mustard? ___________

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download