Name:
pH Lab
The pH scale is used to measure the strength of an __________ or a _______________. The
pH scale runs from ____ to ____.
________- a substance with a pH _____________ than 7.0
-The __________ the pH, the more acidic the solution
____________- a solution in which the pH is ____________ to 7.0
-Water is an example of a neutral solution
______________- have a pH that is ________________ than 7.0
-The ________ the pH, the more basic (or alkaline) the solution
pH scale:
Neutral
--------------------------------------------------------------------
Strong

Weak   Weak

Strong
acid
acid
base
base
__________help maintain homeostasis by minimizing changes in pH.
pH of Common Substances Lab
Pre-Lab Questions:
1. What does pH measure?
2. What is the pH value of a neutral solution? Give an example!
3. Is the pH of a strong base higher or lower than the pH of a weak base?
4. Is the pH of a strong acid higher or lower than the pH of a weak acid?
Name:
Procedure:
1. Pour small amounts of each substance to be tested into an appropriately labeled cup
2. Following the directions for the pH strips, take a pH reading of each substance and record
it in the table. Determine whether the substance is an acid or a base.
3. Compare your results to your predictions and to the results of the rest of the class.
Hypotheses:
Form hypotheses stating whether you think each substance will be an acid, a base, or neutral.
a. Lemon Juice:
b. Windex:
c. Dish soap:
d. Baking soda/water:
e. Tap water:
f. vinegar
g. Bleach
h. egg white
Data Table
Substance
Predicted pH
Predicted acid or
base?
Actual pH
Actual acid or
base?
Lemon Juice
Windex
Dish Soap
Baking
soda/water
Tap water
Vinegar
Bleach
Egg White
Using the data from Table 1, add labels showing the pH of each test substance to the pH scale
below.
0
1
2
3
4 5
6
7
8
9
10
11
12
13
14
Acids
Bases
Results/Conclusion Questions:
1. How did your predictions compare with your results? Why did you think certain substances
would be acidic or basic?
2. Which substance was the strongest acid? ________________ Weakest base? ____________
3. In living things, pH is maintained within a narrow range because it is vital for homeostasis.”
This means …