Exothermic reaction and some examples are as follows :
An exothermic reaction is a chemical reaction that releases heat and has a negative enthalpy (-ΔH) and a positive entropy (+ ΔS). These reactions are energetically favorable and often happen spontaneously, but sometimes you need a little extra energy.
Exothermic reactions make interesting and exciting demonstrations of chemistry because the release of energy often includes sparks, flames, smoke or sound, in addition to heat. Reactions range from safe and gentle to dramatic and explosive.Exothermic reaction and some examples are explained here
Exothermic reaction of steel wool and vinegar
Rust in iron or steel is an oxidation reaction – really a slower form of combustion . While waiting for rust to form would not be an attractive chemical demonstration, there are ways to speed up the process. For example. you can react the steel wool with the vinegar in a safe exothermic reaction which gives off heat.
See how to react steel wool and vinegar
Exothermic reaction of barking dog
The “barking dog” reaction is a demonstration of preferred exothermic chemistry because it emits a sound “woof” or “bark”, similar to that of a dog. You will need a long tube of glass, nitrous oxide or nitric oxide and carbon disulfide for this reaction.
If you don’t have these chemicals, you can do another reaction using a bottle and rubbing alcohol. It’s not as loud or energetic, but it does produce a nice flame and an audible “woofing” sound.
- How to do the Classic Dogking Barking reaction
- Alternative barking dog reaction
Safe laundry detergent Exothermic reaction
Probably the simplest and easiest exothermic reaction is the one you can try at home. Just dissolve the powdered laundry detergent in your hand with a small amount of water. Feel the heat?
Learn more about the exothermic laundry detergent reaction
Elephant toothpaste Exothermic reaction
No list of exothermic reactions would be complete without the popular reaction of toothpaste to the elephant. The heat of this chemical reaction is accompanied by a foam fountain.
The classic form of the demonstration uses a solution of hydrogen peroxide, potassium iodide and a detergent. There is also a child-friendly version of the reaction that uses household yeast and peroxide and is safe enough for young hands to touch.
- Try the elephant toothpaste reaction
- Try the kid-friendly elephant toothpaste project
Exothermic reaction with sulfuric acid and sugar
The reaction of sulfuric acid with ordinary table sugar (sucrose) results in an energetic exothermic reaction. Dehydrating the sugar pushes a steaming column of carbon black, the more it makes the whole room feel like burnt marshmallows.
Learn to make the reaction of sulfuric acid and sugar
Exothermic thermothermal reaction
The thermite reaction is very similar to steel wool rusted with vinegar, except that the oxidation of the metal occurs much more vigorously. Try the thermite reaction, you want to burn metal and a lot of heat.
If you think “go big or go home”, then try the thermite reaction inside a block of dry ice. This amplifies the process and can even produce an explosion.
- Steps to perform the thermite reaction (safely)
- How to Make Etch a Thermite Crust
Sodium or other alkali metal in water
If burning metals is your cup of tea, you can’t go wrong by dropping any alkali metal in the water (unless you add too much). Lithium, sodium, potassium, rubidium and cesium all react in water. When you lower the group into the periodic table, the energy of the reaction increases.
Lithium and sodium are relatively safe. Be careful if you try the project with potassium. It’s probably best to leave the exothermic reaction of rubidium or cesium in the water to people who want to become famous on YouTube. If it is you, send me a link and I will show your risky behavior.
Try the sodium in the water reaction (Safely)
Starting lights without matches
Some exothermic chemical reactions erupt spontaneously without the need for the aid of a lit match. There are many ways to make a chemical fire – all of them fantastic demonstrations of exothermic processes.
Learn how to make chemical fire without matches
Making hot ice is an exothermic reaction
Hot ice is what you get when you solidify sodium acetate from a supercooled solution. The resulting crystals resemble water ice, except that they are hot instead of cold. It’s a fun example of an exothermic reaction. It is also one of the common reactions used to make chemical hand warmers .
While you can buy sodium acetate, it is also very easy to make this chemical by mixing baking soda and vinegar and boiling the excess liquid.
Make hot ice
No more exothermic reactions to try
Many chemical reactions release heat, so these popular exothermic reactions are not your only options. Here are some other interesting demonstrations to try:
- Make Vesuvius Fire
- Make a baking soda and vinegar (yes, it’s exothermic)
- Magic Genie in a demonstration of bottled chemistry
- Instant fire demonstration
- Dance Rubber Bears
- Dance charcoal
- Thunderstorm test tube
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- What is an endothermic reaction