P HAnalysis SE

Name: ______________________________________ Date: ________________________
Student Exploration: pH Analysis
Vocabulary: acid, acidic, alkaline, base, indicator, neutral, pH
Prior Knowledge Questions (Do these BEFORE using the Gizmo .)
1. Acids are substances that produce hydrogen ions (H+) when dissolved in water. Lemon
juice is an example of an acid.
It taste acitic without any
A. What does lemon juice taste like? ________________________________________
It burns
B. What does it feel like if lemon juice gets in your eye? _________________________
2. Bases are substances that produce hydroxide ions (OH -) when dissolved in water. Hand
soap is an example of a base.
It feels like boubles
A. What does soap feel like? ______________________________________________
I don't know
B. What does soap taste like? _____________________________________________
It burns a lot worse than any other excruciating pain

C. What does it feel like if soap gets in your eye? ______________________________
that you've ever felt.
Gizmo Warm-up
The strength of an acid or base is measured on the pH scale.
The term “pH” is short for “potential of hydrogen.” It is a measure
of how many excess H+ ions there are in a solution. The pH scale
runs from 0 to 14, with 0 representing the highest concentration
of hydrogen ions. Acidic substances have a pH below 7, while
alkaline substances (bases) have a pH above 7. Pure water has
a pH of 7 and is considered neutral.
The pH Analysis Gizmo allows you to find the pH of a variety of

liquids. In the Gizmo, check that the Substance in the tube is
Ammonia, and click Test. Wait until the animation is finished.
white
1. Indicators change color in acids or bases. What is the color of the pH paper? ___________
10.6
2. Compare the paper to the pH color chart. What is the pH of ammonia? _____________
alkaline
3. Is ammonia acidic or alkaline? _____________
2019
Get the Gizmo ready:
Activity A:
 Click Reset.
Measuring pH
 Check that the 0-14 paper is selected.
Goal: Find the pH of 18 common substances.
1. Test: Use the Gizmo to find the pH of each of the available substances. Classify each
substance as acidic (pH < 7), alkaline (ph > 7), or neutral (pH = 7).
0-14 pH indicator paper

Material in the tube pH value Acidic, alkaline, or neutral?
Baking soda 8 alkaline
Bleach 10 alkaline
Coffee 5 acidic
Cola 2 acidic
Drain cleaner 14 alkaline
Hand soap 10 alkaline
Juice (lemon) 3 acidic
Juice (orange) 3 acidic
3
Juice (tomato) acidic
Milk 6.4 acidic
Milk of magnesia 10 alkaline
Oven cleaner 14 alkaline
Saliva (human) 6 acidic
Shampoo 6 acidic
Stomach acid 1 acidic
4
Vinegar acidic
Water (distilled) 7 neutral
8
Water (ocean) alkaline
2. Summarize: Compare all the acidic substances and all the alkaline substances.
In general the substances that are sour are

A. In general, what types of substances tend to be acidic? _______________________
the ones that typically are acidic
___________________________________________________________________
B. What types of substances tend to be alkaline? ______________________________
The substances that will burn you or execute you if

___________________________________________________________________
you drink/eat it
2019
Get the Gizmo ready:
Activity B:
 Click Reset.
More accurate pH
 Select the 4.5-7.5 paper.
Goal: Find the pH of substances in a more accurate way.
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.
4.5-7.5 pH indicator paper

Material in the tube pH value (0 to 14 paper) pH value (4.5 to 7.5 paper)
Coffee 5.5 5.5
Milk 6.5 6.5
Oven cleaner 14 7
Saliva (human) 6.5 6.5
Shampoo 6 5.5
Stomach acid 1 4.5
Water (distilled) 7 7
2. Analyze: Compare the pH values in each column.

Most of them have similar numbers
A. How do these values compare? _________________________________________
___________________________________________________________________
B. What is an advantage of using the 4.5-7.5 paper? ___________________________

the result has more accuracy than the
0-14 paper
___________________________________________________________________
C. What is a disadvantage of using the 4.5-7.5 paper? __________________________

the result for alkaline substances sometimes are weird like for the oven cleaner, on the 0-14 paper it was 14 but on
___________________________________________________________________
the 4.5-7.5 paper it was 7
D. Given the results from two kinds of indicator paper, which substances appear to be
The water
neutral (pH = 7)? _____________________________________________________
2019

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Name: ______________ Date:

Student Exploration: pH Analysis

Vocabulary: acid, acidic, alkaline, base, indicator, neutral, pH

Prior Knowledge Questions (Do these BEFORE using the Gizmo .)

It burns a lot worse than any other excruciating pain

The pH Analysis Gizmo allows you to find the pH of a variety of

Goal: Find the pH of 18 common substances.

0-14 pH indicator paper

In general the substances that are sour are

B. What types of substances tend to be alkaline? ______________________________

The substances that will burn you or execute you if

Goal: Find the pH of substances in a more accurate way.

4.5-7.5 pH indicator paper

2. Analyze: Compare the pH values in each column.

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? __________________________

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