pH Analysis Gizmo Answer Key

Name: Alexander Ford Date: 07-04-2022 Student Exploration: pH Analysis Directions: Follow the instructions to go through the simulation. Respond to the questions andprompts 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? Sharp, tangy taste B. What does it feel like if lemon juice gets in your eye? My eyes would sting and burn. 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? Smooth and slippery B. What does soap taste like? Sour and bad C. What does it feel like if soap gets in your eye? Your eye burns and hurts 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 thehighest 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. 1. Indicators change color in acids or bases. What is the color of the pH paper? coral pink, orange, blue,and yellow 2. Compare the paper to the pH color chart . What is the pH of ammonia? 11 Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

3. Is ammonia acidic or alkaline? alkaline Activity A: Measuring pH 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). 0-14 pH indicator paper Material in the tube pH value Acidic, alkaline, or neutral? Baking soda 8 Alkaline Bleach 11 Alkaline Coffee 5 Acidic Cola 2 Acidic Drain cleaner 13 Alkaline Hand soap 9 Alkaline Juice (lemon) 2 Acidic Juice (orange) 3 Acidic Juice (tomato) 5 Acidic Milk 7 Neutral Milk of magnesia 10 Alkaline Oven cleaner 13 Alkaline Saliva (human) 6 Acidic Shampoo 6 Acidic Stomach acid 1 Acidic Vinegar 4 Acidic Water (distilled) 7 Neutral Water (ocean) 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? Acids and juices B. What types of substances tend to be alkaline? Cooking supplies and cleaners Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

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. 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 Milk 7 6.5 Oven cleaner 13 7.5 Saliva (human) 6 6.5 Shampoo 6 7 Stomach acid 1 4.5 Water (distilled) 8 7 2. Analyze: Compare the pH values in each column. A. How do these values compare? They are almost the same amounts B. What is an advantage of using the 4.5-7.5 paper? Smaller acidic and alkaline range C. What is a disadvantage of using the 4.5-7.5 paper? The range of some amounts is too narrow. D. Given the results from two kinds of indicator paper, which substances appear to be neutral (pH = 7)? Water, milk, distilled and shampoo. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved