George Lee Honors Biology p H Gizmo-2020 PDF

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Summary

Course work from this class. This delves into the topic of cellular respiration and this document should only be used for learning purposes....

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Name:

George Lee

Date:

9/22/2020

Student Exploration: pH Analysis: Quad Color Indicator Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. 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. A. What does lemon juice taste like?

Sour

B. What does it feel like if lemon juice gets in your eye?

When lemon juice gets in your eye, it burns.

2. Bases are substances that produce hydroxide ions (OH-) when dissolved in water. Hand soap is an example of a base. A. What does soap feel like?

Soap feels smooth.

B. What does soap taste like?

Soap tastes sour.

C. What does it feel like if soap gets in your eye?

When soap gets in your eyes, it burns.

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: Quad Color Indicator 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. 1. Indicators change color in acids or bases. What is the color of the pH paper?

The color of the pH paper is orange, blue, reddish pink, and

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yellow. 2. Compare the paper to the pH color chart. What is the pH of ammonia?

Is ammonia acidic or alkaline?

Activity A: Measuring pH

The pH of ammonia is 11. Ammonia is alkaline.

Get the Gizmo ready: ● Click Reset. ● 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).

Material in the tube Baking soda Bleach Coffee Cola Drain cleaner Hand soap Juice (lemon) Juice (orange) Juice (tomato) Milk Milk of magnesia Oven cleaner Saliva (human) Shampoo Stomach acid Vinegar Water (distilled) Water (ocean)

0-14 pH indicator paper pH value Acidic, alkaline, or neutral? 8 alkaline 11 alkaline 5 acidic 2 acidic 13 alkaline 9 alkaline 2 acidic 3 acidic 4 acidic 7 neutral 10 alkaline 14 alkaline 7 neutral 7 acidic 1 acidic 4 acidic 7 neutral 8 alkaline

2. Summarize: Compare all the acidic substances and all the alkaline substances. A. In general, what types of substances tend to be acidic? In general, the types of substances that tend to be acidic, are juices, drinks, and acids. B. What types of substances tend to be alkaline? Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

The substances that tend to be alkaline, are cleaners and cooking supplies.

Activity B: 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. 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)

4.5-7.5 pH indicator paper pH value (0 to 14 paper) 5 7 14 7 6 1 7

pH value (4.5 to 7.5 paper) 5 6.5 7.5 6.5 7 4.5 7

2. Analyze: Compare the pH values in each column. A. How do these values compare? The pH values are almost the exact same. B. What is an advantage of using the 4.5-7.5 paper? The advantages of using the 4.5-7.5 paper, is that there is a smaller alkaline and acidic range. C. What is a disadvantage of using the 4.5-7.5 paper? The disadvantage of using the 4.5-7.5 paper, is that the range is too small for some amounts. D. Given the results from two kinds of indicator paper, which substances appear to be neutral (pH = 7)?

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Given the results from the two kinds of indicator paper, the substances that appear to be neutral are distilled water and shampoo.

Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved...