Activity B:

Question

More accurate ph
Get the Gizmo ready:
• Click Reset.
Select the 4.5-7.5 paper.
Goal: Find the pH of substances in a more accurate way.
EASES
6 65 7
pH color chart
1. Test: Before you begin testing with the 4.5-7.5 paper, list the pH values of the substances below that you found using the 0-14 pH indicator paper. Then find the pH of each substance with the 4.5-7.5 paper.
Material in the tube
Coffee
Milk
Oven cleaner
Saliva (human)
Shampoo
Stomach acid
Water (distilled)
2. Analyze: Compare the pH values in each column.
A. How do these values compare?
4.5-7.5 pH indicator paper pH value (0 to 14 paper)
pH value (4.5 to 7.5 paper)
5
6.5 to 6.9
13
6
6.2-7.6
6.5
7.5
6.5
6
4.5
B. What is an advantage of using the 4.5-7.5 paper?
C. What is a disadvantage of using the 4.5-7.5 paper?
D. Given the results from two kinds of indicator paper, which substances appear to be
neutral (pH = 7)?

Answer 1

A. The values using the 4.5-7.5 paper are generally more accurate and precise compared to the values obtained using the 0-14 pH indicator paper.

B. One advantage of using the 4.5-7.5 paper is that it provides a more narrow range, allowing for more precise pH measurements within the slightly acidic to neutral range.

C. A disadvantage of using the 4.5-7.5 paper is that it may not be as versatile as the 0-14 pH indicator paper, which covers a wider pH range from acidic to alkaline.

D. Based on the results, the substances that appear to be neutral (pH = 7) are water (distilled) and stomach acid.