Exothermic Reaction( Myisha Morgan)

Title: Cellular Respiration using a Exothermic Reaction (Elephants Toothpaste)

Principle(s) Investigated: Engage, Explore, Explain, Elaborate, Evaluate,

Standards: (MS-LS1-1) Conduct an investigation to produce data to serve as the basis for evidence that meet the goals of an investigation.

Materials: A clean 12 or 16 ounce plastic soda bottle, 1/2 cup measuring, 20-volume hydrogen peroxide liquid, (20-volume is a 6% solution, 30-volume is a 9% and 40-volume is 12%,) 1 tablespoon of dry yeast, 3 tablespoons of warm water, liquid dish washing soap, food coloring, small cup, safety goggles

Procedure: Hydrogen peroxide can irritate skin and eyes, so please don't let the students poor in the hydrogen peroxide. safety goggles. Please wear safety googles while pouring in the hydrogen peroxide.

Step 1. Add 8 drops of your favorite food coloring into the bottle.

Step 2. Add about 1 tablespoon of liquid dish soap into the bottle and swish the bottle around a bit to mix it.

Step 3. In a separate small cup, combine the warm water and the yeast together and mix for about 30 seconds.

Step 4. Pour the yeast water mixture into the bottle (a funnel will help) and watch the foam begin to form.

Student prior knowledge: Students should know cellular respiration, decomposition and exothermic reaction. We will be comparing this project to cellular respiration. This experiment is similar to the Hydrogen peroxide, H₂O₂, in our bodies which is a toxic (poisonous) by-product of respiration. Most living things, including yeast, contain an enzyme that helps the breakdown of hydrogen peroxide into other substances that are not poisonous. The reaction between hydrogen peroxide and yeast is similar to the breakdown of hydrogen peroxide that can occur in the cells of your body. When a chemical that is made up of only one molecule breaks down into two different, smaller molecules, this is called a decomposition reaction. This particular decomposition reaction (compound is broken into smaller chemical species) can also create an ’exothermic’ reaction, meaning it gives off heat. In this case, heat is released during the reaction, elevating the temperature of the reaction mixture

Explanation: Hydrogen peroxide is H2O2, or 2 hydrogen atoms and 2 oxygen atoms. When you add yeast to the mix, the fungi immediately aid in the decomposition of the hydrogen peroxide, stripping off that extra oxygen. The foam is special because each tiny foam bubble is filled with oxygen. The yeast acted as a catalyst (a helper) to remove the oxygen from the hydrogen peroxide. The foam in the bottle is warm because it is exothermic, it releases heat. If you feel the sides of the bottle, the plastic should feel warm.

Questions & Answers:

1. Question: What happens if you use a more concentrated solution with a straighter beaker.

Answer: The solution will come out faster and shoot up straighter.

2. Question: What happens when yeast is added to the mix?

Answer: The yeast goes through the process of cellular respiration. This is toxic to the cells so it must be converted into non-toxic chemicals. Hydrogen peroxide is broken down using a protein this is called catalase. It works as a helper that is why it is called a catalyst in this experiment. A catalyst speeds up the rate of the chemical reaction without changing its products.

3. Question: How do humans break down toxic hydrogen peroxide in their systems?

Answer: Through our metabolism, the breakdown of H₂O₂ happens very slowly in our cells. In this experiment, the yeast is added to the hydrogen peroxide to speed up the reaction. The catalase in the yeast speeds up the process of breaking down the H₂O₂ and produces O₂ and H₂O more quickly. The oxygen gets trapped by the dishwashing detergent as many tiny bubbles. That is also why H₂O₂ foams when poured onto a cut: the catalase in our tissues breaks the H₂O₂ down in to water and oxygen.

Applications to Everyday Life:

1. We can compare this experiment to cellular respiration, this happens in the body every day.

2. Fire is an exothermic reaction that occurs much faster. When a fuel is burning, it releases heat, which can easily be felt very quickly.

3. Rust is another example of an exothermic reaction that releases heat. Rust is iron oxide (Fe₂O₃), which is produced by the reaction of iron (Fe) with oxygen (O₂). It takes place at such a slow pace that it is impossible to observe a difference of temperature on a piece of steel.

Photos

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