Docstoc

pH_Gizmo_Lab

Document Sample
pH_Gizmo_Lab Powered By Docstoc
					Name: ___________________                                                Online Quiz (5pts) _____
                                                                         Written Lab (5pts) _______
Per: _______ Date: _________                                                         Total _______
                                                                                               10 pts
                        Life Science pH Analysis Lab
PRE-LAB BACKGROUND
Have you ever heard a product advertised as "pH balanced"? The abbreviation "pH" is short for "power
of hydrogen." It is a measure of hydrogen ion concentration. The pH scale is used to measure whether
a substance is an acid (acidic), a base (alkaline), or neutral.
The pH scale ranges from 0 to 14. A substance with a pH of 7, such as pure water, is neutral.
Substances with a pH between 0 and 7 are acids (H+). Substances with a pH between 7 and 14 are
bases (OH-).
Plants depend on soil having the right pH level for proper growth, and our bodies must maintain the
proper pH level to function properly and enzymes to work. In addition, scientists and engineers use pH
information when creating batteries, soft drinks, detergents, medicine, and more.

PROCEDURE
   1) Go to www.explorelearning.com and login.
   2) Select pH Analysis Lab.
   3) Follow outline of this lab handout. Test all items and compare with the color reference chart to
      determine the pH and record results.
   4) Fill in all charts and answer questions.
   5) When done testing, scroll down to quiz questions and take quiz.
   6) Your score is a combination of this lab write up and your online quiz.

DIRECTIONS:
In this activity, you will use                            0-14 pH indicator paper
pH indicator strips to               Material in the                          Acidic, alkaline, or
                                                              pH value
determine the pH level of                tube                                      neutral?
various common                          Baking soda
substances. Under pH                      Bleach
indicator paper strip type,               Coffee
be sure that 0-14 paper is                 Cola
selected. Look at the pH               Drain cleaner
color chart in the Gizmo™.              Hand soap
This chart allows you to               Juice (lemon)
match colors from a test
                                       Juice (orange)
strip of 0-14 paper to get a
                                       Juice (tomato)
pH value for a substance.
                                            Milk
                                      Milk of magnesia
                                       Oven cleaner
                                      Saliva (human)
                                         Shampoo
                                       Stomach acid
                                          Vinegar
                                      Water (distilled)
                                       Water (ocean)
QUESTIONS:
   1) On the pH color chart, do colors in the red-orange family indicate that the substance is an acid
      or a base? (Remember, pH between 0 and 7 is an acid, and pH between 7 and 14 is a base.)


   2) On the pH color chart, do colors in the blue-green family indicate that the substance is an acid
      or a base?


   3) In general, what types of substances are strong bases?


   4) In general, what types of substances tested are strong acids?


   5) Which substance is neutral?


USING THE 4.5 TO 7.5 PH INDICATOR PAPER STRIP:
In this activity, you will use a narrow range pH test paper strip to find pH values for some of the
substances in the Gizmo. In the Gizmo, under pH indicator paper strip type, choose 4.5-7.5 paper.
(With this paper, you can test pH with a precision of 0.5 rather than 1.)




   6) For substances with a pH value that measured between 4.5 and 7.5 on the 0-14 paper, how did
      the pH value from the 4.5-7.5 paper compare to the pH value from the 0-14 paper?


   7) What advantage do you see to using the 4.5-7.5 paper to measure pH?


   8) What disadvantage do you see to using the 4.5-7.5 paper to measure pH?


CONCLUSION
(Talk about how the pH scale works, why water is neutral, and how pH is important in biology.)

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:22
posted:12/1/2011
language:English
pages:2