The Exothermic reactions Are those chemical reactions that transfer energy in the form of temperature to the bodies that surround it.
When a chemical reaction occurs, energy is transferred from or to the surroundings of a body, causing a change in the temperature in its environment (Arrington, 2017).
In the course of daily life it is common to see how different or exothermic reactions take place naturally or triggered that generate changes in the temperature of different places.
These temperature changes can be measured with the help of a thermometer (BBC, Science, 2014).
The word"exothermic"comes from the words"exo"meaning"out"and"terms"meaning temperature. In this way, it is concluded that the exothermic reactions are those that release temperature to the outside.
Opposite to these reactions are endotherms, which absorb energy (BBC, 2014).
Energy is manifested in many forms, including temperature, light, sound, or electricity.
Energy is usually obtained when the bonds between the molecules of the materials are broken, since most of the energy contained in the material is found in these bonds.
When a reaction causes the rupture of these bonds, it causes the energy in them to be released, generating an exothermic reaction.
Examples of exothermic chemical reactions
Exothermic reactions are always accompanied by an increase in temperature, and mostly by sparks, flames, smoke, or some sound (Helmenstine, 2016).
Among the most common examples of exothermic reactions can be listed the following:
1 - Steel Shavings + Vinegar : This mixture works as a form of slow combustion where the steel undergoes a process of oxidation thanks to the action of the vinegar.
2 -"Dog Bark" : This reaction is given this name since it gives off a sound similar to the barking of the dog.
This reaction is carried out inside a laboratory tube where nitrous oxide and nitric oxide and carbon bisulphate are mixed.
3 - Glass Bottle + Alcohol : Similar to the reaction generated by the experiment named above, is to rub a glass bottle with alcohol in such a way as to produce a flame.
4 - Laundry Detergent + Water : When detergent laundry soap is dissolved, the presence of an exothermic reaction can be observed.
This is one of the examples of exothermic reactions more easily observed in the home.
5 - Elephant toothpaste : This is an experiment commonly used to explain the dynamics of exothermic reactions.
It consists of the dissolution of hydrogen peroxide in some soapy medium, in order to produce a large amount of foam.
To this mixture is added a catalyst (potassium iodide) that helps the rapid decomposition of the peroxide.
6 - Sulfuric Acid + Sugar : The process of dehydration of the sugar produces an evident exothermic reaction.
When sulfuric acid is mixed with sugar, it is dehydrated and a column of black smoke appears, causing the environment to smell burnt.
7 - Termite : Termite is a volatile mixture of aluminum and oxide. This mixture produces an exothermic reaction known as the termite reaction, where a large amount of heat and light are produced at the time the mixture reacts.
8 - Sodium + Water : Sodium or any alkaline medium reacts strongly with water. When any alkali metal is added to the water (lithium, sodium, potassium, rubidium or cesium) it must react.
To the extent that the number of the element is greater in the periodic table, the reaction will be stronger.
9 - Sodium Acetate : Sodium acetate is known as hot ice. This material is part of the crystallization of frozen solutions that, instead of releasing cold, release heat.
By its appearance, it is called"ice", but in reality, crystallized sodium acetate is one of the materials most commonly used to make hand warmer.
10 - Soda + Vinegar : This mixture produces an exothermic reaction that generates large amounts of foam, therefore, is commonly used to resemble the explosion of a volcano.
11 - The Genie of the Bottle : In this experiment, hydrogen peroxide (hydrogen peroxide) is mixed with potassium permanganate.
In this way, the permanganate decomposes the hydrogen peroxide, causing a great amount of smoke and heat to be released.
12 - Explosive Rubber Bears : Rubber bears are rich in sucrose (sugar), a substance that when mixed with potassium chlorate at high temperature produces a violent explosion and the movement of the rubber bears.
13 - Lightning in a Tube : This reaction occurs when a corrosive acid is mixed with alcohol or acetone.
In this way, you can see a vigorous chemical reaction that results in the generation of light inside a tube similar to a lightning.
14 - Freezing Water : During this process the water releases energy in the form of heat, therefore, when ice cubes are frozen, an exothermic reaction takes place.
15 - A Burning Candle : The process of burning paraffin and candle wick produces an exothermic reaction that generates heat and light (TutorVista, 2017).
16 - Burning firewood : Like the combustion of paraffin, burning the wood produces an exothermic reaction in that the product resulting from this reaction manifests as heat and temperature.
17 - Breathing : It is the breathing process produces an exothermic reaction to the interior of the cells during the gas exchange.
In this way, glucose along with oxygen is transformed into carbon dioxide and heat.
18 - Corrosion of Metals : Pure metals, ie in their natural state when coming into contact with air, produce an oxidation reaction together with the generation of heat, therefore, it is said that this process is exothermic.
19 - Gas Combustion Process : The combustion process of any gas, such as methane or natural, produces an exothermic reaction that manifests itself in the generation of heat and sometimes, when combustion occurs in a controlled way, can also produce light.
20 - Lighting a Match : When a phosphor is ignited, a reaction is generated between the chemicals that compose it and the oxygen present in the air.
In this way, an exothermic reaction is generated that produces both light and heat (Helmenstine A. M., 2017).
References
- Arrington, D. (2017). com . Obtained from Exothermic Reaction: Definition & Example: study.com
- (2014). BBC . Obtained from Energy changes and reversible reactions: bbc.co.uk
- (2014). Science . Obtained from Energy changes and reversible reactions: bbc.co.uk
- Helmenstine, A. (March 9, 2016). Science Notes . Obtained from Exothermic Reactions - Definition and Examples: sciencenotes.org
- Helmenstine, A.M. (March 1, 2017). Thoughtco . Obtained from Exothermic Reaction Examples - Demonstrations To Try: thoughtco.com
- (2017). TutorVista.com . Retrieved from Exothermic Reaction: chemistry.tutorvista.com.