Neutralization Lab - Lemon Chug (Concetta Langford)

Title: Neutralization of an Acid and a Base ("Lemon Chug")

Principle(s) Investigated: We will be investigating how to neutralize a reaction, and what products we get when we combine an acid and a base to produce a chemical reaction.

Standards:

Materials: All materials can be obtained at the grocery store and/or the dollar store.

TEACHER MATERIALS:

• Measuring spoons - 1 Tbsp, 1/2 Tsp, 1/4 Tsp
• Baking Soda (1/2 tsp per student)
• Lemon juice ( 2 Tbsp per student)
• Sugar (2 Tbsp per student)

STUDENT MATERIALS (per team)

• 10 oz cup per person
• 2 cup measuring cup
• 1 bowl with 10 Tbsp sugar
• 1 lab towel
• 1 napkin per person
• 1 spoon per person

Procedure:

The teacher creates a story to go with this lab. The story tells the steps of the lab. Here is the basic outline of steps, without the story portion:

• Students add 1/2 cup of water to their cups and take a small drink of water
• Students add 2 Tbsp lemon juice to simulate their stomach acids, then they take a drink of the very sour lemon water.
• Students add as much sugar as they would like (up to 2 Tbsp) in order to make a sweet lemonade type drink.
• They have created an acidic drink. Students should drink their sweet lemonade down so the cup is only 1/2 full (otherwise it will overflow when they add the baking soda).
• Review what happens when we add an acid to a base, and what products we expect to see.
• Have the students create lemon soda by adding 1/2 tsp baking soda, quickly stir once, then chug the liquid down.

Student prior knowledge:

The students have been working on lessons about chemical vs. physical change. They have done reactions and had to explain if a physical (reversible) change has occurred, or if a chemical (non-reversible) change has occurred. They have also been working for several days on creating a pH scale and labeling different compounds as acidic, basic or neutral. The students did labs to determine the acidity or basic status of compounds as well. This lab (Lemon Chug) was done as a fun way to end the pH series of lessons and to for cumulative knowledge in how to neutralize a solution, as well as to emphasize what products we always get from an acid-base reaction.

pH Scale

Explanation:

In order to neutralize the acidic lemon juice and the basic baking soda, we are combining them together. Once their reaction is complete, the remaining liquid in the cup will be "most like water", which is what our students were taught about being neutral (neutral substances are "most like water"). When an acid and a base combine, they produce three products -- water, carbon dioxide and salt. The trick to this lab is to drink the lemon soda before it has time to complete it's reaction. If you drink it quickly, it tastes like sweet lemon soda. If you wait a little too long, it tastes like salt water. The students like the trick, as those that wait too long end up doing dramatic spitting out of the liquid and their classmates video the results. You can have the students compete with each other to see who can chug their soda the fastest.

Questions & Answers:

1. If you put an acid and a base together, what process happens? This is a chemical reaction because the reactants and the products have different properties and the reaction is not reversible.
2. What 3 products are created during an acid-base reaction? Water, Salt, Carbon Dioxide
3. Why do you think these products might cause you to burp if this reaction occurred inside your body? Because the reaction creates carbon dioxide, the bubbles become trapped in your body. In a cup, the bubbles are released into the air. In your body, the bubbles are trapped and they will either come out as a burp or a fart.

Applications to Everyday Life:

1. When you have an upset stomach, it is often due to an excess amount of stomach acids that have been produced. The solution to this is to take an over-the-counter antacid medication, such as Tums. The Tums is basic and it will work to neutralize the acids in your stomach, thus creating a more comfortable environment.
2. Baking powder is a substance used in cooking. It contains both an acid and a base. When baking soda is added to a recipe and it mixes with the other ingredients, it creates water and carbon dioxide gas. The carbon dioxide gas causes the baked goods to rise. If you forget this ingredient, your cake or cookies will be flat.
3. When you neutralize soil it promotes plant growth. Sometimes additives are necessary in order to neutralize the soil. If you live in a place with acidic soil, you can add calcium carbonate to neutralize it. If you live in a place with basic soil, you can add calcium sulfate. Both of these additives are ingredients in different types of fertilizers.

Photographs: Include photos and diagrams that illustrate the how the investigation is performed.

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Videos: Include a video of your investigation