Processes in Producing a Chemical Reaction and Hazards

Published Date: 18 Jan 2018

Elephant Toothpaste

Objective/aim

1. Understand the processes involved in producing a chemical reaction

2. Identify hazards involved with using particular chemicals

3. Demonstrate an understanding of chemistry terms such as catalyst, oxidation, and exothermic (Harper & Nickels, 2008).

Background Information

The elephant toothpaste experiment is an experiment that produces great amount of steaming foam (Helmenstine, 2014). Its great amount of foam is what makes it look like a toothpaste an elephant would use. The experiment makes use of hydrogen peroxide (H₂O₂) solution. Hydrogen peroxide is a germiadral agent composed of water and oxygen. It kills disease organisms, like ozone does, using oxidation. It kills microorganisms by oxidizing them which can be described as a “Controlled burning process” (Hinrichs, 1986).

When hydrogen peroxide reacts with organic material, it breaks down into oxygen and water. It can be used in varies ways example, disinfection, mouthwash, hair lightening and contact lenses. In our bodies hydrogen peroxide is produced to fight infections, which must present for our immune systems to function correctly and healthy (Helmenstine, 2014). White blood cells are known as leukocytes, a sub-class of these cells ‘Neutrophils’ produces hydrogen peroxide as the first defence against toxins, parasites, bacteria, viruses and yeasts (Helmenstine, 2014).

Hydrogen peroxide is most used in toothpastes and as a cure for toothaches. In this experiment we also use yeast or saturated potassium iodide solution as a catalyst to make the peroxide molecule release the oxygen faster (Harper & Nickels, 2008). Yeast is a fungi which converts the catalase hydrogen peroxide into harmless water and oxygen (Spangler, 2013). The overall equation for this reaction is:

2 H₂O₂ (aq)  2 H₂O (l) + O₂ (g)

The decomposition of the hydrogen peroxide into water and oxygen is catalysed by the iodine ion or dry yeast. It also releases a small amount of the heat so the reaction is exothermic. (Helmenstine, 2014)

H₂O₂ (aq) + OI^- (aq)  I^- (aq) + H₂O (l) + O₂ (g)

The dishwashing detergent used captures oxygen as bubbles. Food colouring adds colour to the foam which can be optional.

Chemicals and Materials

You will need:

• 20mL Hydrogen peroxide (30%)
• 5mL Sodium iodide solution 2M
• Dishwashing liquid
• Food colouring
• Rubber gloves for clean up (Harper & Nickels, 2008).

Labware and apparatus

• A funnel
• Dropper
• Beaker
• 500 mL Graduated cylinder
• Safety goggles
• Plastic bottle (2l Cold drink bottle)
• Glass rob
• Spatula

Safety

Hazards:

• The bottle will become very hot. Allow the bottle to cool before touching it directly.
• Hydrogen peroxide is a very strong oxidizing agent and may cause severe skin burns. Store hydrogen peroxide in a cool, dark area away from reducing agent and organic materials.
• Do not lean over the bottle when solutions are mixed it is an exothermic reaction.
• Experiment should not be done near an open flame.
• The solution can be washed down the drain with excess water (Carolina.com., 2014).

Experimental Procedure

1. Put on your goggles and gloves.

2. Have a couple of students feel the side of the graduated cylinder.

3. Measure 60ml of hydrogen peroxide from your source bottle into the beaker. Pour the entire 60ml into the bottom of your container.

4. Place 10g of potassium iodide in the plastic portion cup. Add 10ml of water and 3ml of liquid detergent. Stir all the chemicals together using a wooden stick.

5. Open the bottle of food colouring mixed half and half with glycerine or corn syrup and exactly 2ml of the dye. Dribble it down one side of the container that you are using.

6. Add the mixture of soap, water and potassium iodide to the hydrogen peroxide in the container. The potassium iodide will separate into potassium and iodide ions.

7. Once the experiment is complete ask a couple of students to come up and carefully touch the sides of the bottle and describe the temperature for all the other students in the laboratory (Meerman, 2009).

Outcome of experiment

The experiment produces a large amount of foam as a result of the dishwashing detergent that was added. The foam shoots out of the container like toothpaste would if you squeezed the container. The foam produced is safe to play around with as they only contain soap and oxygen from the hydrogen peroxide. We will also observe the catalytic reaction rate by the combining of yeast, hydrogen peroxide and dish washing liquid detergent (Spangler, 2013).

Source of experiment

Steve Spangler Science. (2008). Elephants toothpaste. Retrieved October 30, 2008, from

www.stevespanglerscience.com.

Material safety

Hydrogen Peroxide

Personal Protective Equipments

Eyes: Wear appropriate protective eyewear or chemical safety goggles.

Skin: Wear appropriate gloves to prevent skin exposure.

Clothing: Wear appropriate clothing to prevent skin exposure.

Potential Health Effects

Eye:Contact with eyes can cause severe burns and corneal damage.

Skin: Cause severe skin irritation and possible burns. May cause skin irritation, redness, swelling and formation of blisters.

Ingestion: Causes Nausea, vomiting and diarrhoea, gastrointestinal tract burns. May cause difficulties in swallowing, stomach distension, possible cerebral swelling and death. Ingestion might also result in irritation of the esophagus, bleeding of the stomach and ulcer formation.

Inhaling: Can cause burns in the respiratory tract causing nasal tissue, insomnia, nervous tremors with numb extremities, chemical pneumonia unconsciousness and death. At high concentration respiratory effects may cause acute lung damage and delayed pulmonary oedema.

Chronic: Can cause dermatitis due to prolonged or repeated skin contact. Mutagenic effects and corneal damage if repeatedly contacted.

First Aid Measures

Eyes:Get medical aid immediately. Do not rub eyes or keep eyes closed. Extensive irrigation with water is required immediately.

Skin:Get medical aid immediately. Flush skin with plently of water for at least 15 minutes while removing contaminated clothing. Wash clothing before reuse.

Ingestion:Do not induce vomiting. Give 2-4 cups of milk or water, if unconscious don’t give anything, get medical aid immediately. Wash mouth out with water. Vomiting may occur, give water to further dilute the chemical.

Inhalation:Get medical aid immediately. Move person to fresh air immediately. If breathing is difficult, give oxygen. Do not perform mouth to mouth. You can use a bag and a mask for artificial respiration if breathing ceases.

Fire Measure

Use only water, do not use dry chemicals or pour water into containers. Contact professional fire fighters immediately. Cool containers with flooding quantities if water until well after fire is out. For large fires, flood fire area with large quantities of water while knocking down vapours with water fog.

Handling

Wash hands thoroughly after handling. Wash contaminated clothes before reuse. Use only in a well ventilated area. Do not get in eyes, skin or on clothing. Store protected from light. Unused chemical must not be returned to the container.

Storage

Keep away from heat, sparks and flame. Do not store near combustible materials. Keep containers closed when not in use. Store away from light. Store only in light resistant containers fitted with a safety vent.

Questions and Answers

1. What type of reaction is this?

Decomposition (1)

2. What happen to the reaction when the iodine is drop into the hydrogen peroxide?

There is a large amount of heat released and the hydrogen peroxide is decomposes in to water and oxygen. (2)

3. Write the balanced chemical equation for the reaction taking place between the hydrogen peroxide and the iodine.

H₂O₂ (aq) + OI^- (aq)  I^- (aq) + H₂O (l) + O₂ (g)(5)

4. Which enzyme did we add to help break down hydrogen peroxide?

Iodine (1)

5. What is the gas that is being released?

Oxygen (1)

Reference list

Helmenstine, A.M. (2014). Elephant toothpaste chemistry demonstration. Available: Chemistry.about.com/od/chemistrydemonstrations/a/elephant-tooth.htm. [Accessed: 28 August 2014 ].

Himrichs, E.J. (1987). Hospital periodontics a survey of hospital utilization by American academy of periodontology members. Journal of periodontology. 57(11), 663-671.

Harper, A. and Nickels, K. (2008). Elephant’s toothpaste. University of technology: Queensland.

Spangler, S. (2013). Elephant’s toothpaste. Available: www.stevespanglerscience.com/lab/experiments/elephants-toothpaste. [Accessed: 28 August 2014 ].

Carolina.com. (2014). Carolina world class science and maths. Available: http://www.carolina.com/chemistry/experiments/elephant.asp. [Accessed: 27 August 2014].

Meerman, R. (2009). Teacher Demonstration 26: Elephant’s Toothpaste. Available: http://www.abc.net.au/science/surfingscientist/pdf/teachdemo26.pdf. [Accessed: 26 August 2014].

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