Energy Education

Acid: Difference between revisions

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[[Category:Done 2015-07-24]]
[[Category:Done 2018-07-20]]
[[Category:Translated to French]]
[[fr:Acide]]
[[File:Lemon.jpg|250px|thumb|Figure 1. Lemons are acidic, with a pH of around 2.<ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Lemon.jpg</ref>]]
[[File:Lemon.jpg|250px|thumb|Figure 1. Lemons are acidic, with a pH of around 2.<ref>Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Lemon.jpg</ref>]]
<onlyinclude>An '''acid''' is any substance that will react with water to produce H<sup>+</sup> <ref name=libre>Chemistry LibreTexts. (July 11 2018). ''Overview of Acids and Bases'' [online], Available: https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid/Overview_of_Acids_and_Bases </ref> (H<sup>+</sup> reacts in water to produce H<sub>3</sub>O<sup>+</sup>  - both can be treated as equivalent.) Generally, solutions of acid in water will have a [[pH]] less than 7.</onlyinclude>


<onlyinclude>An '''acid''' is any substance with a [[pH]] less than 7. This means that the [[ion]] concentration of [[hydrogen]] (H<sup>+</sup>) is larger than the concentration of hydroxide (OH<sup>-</sup>).</onlyinclude> A lower pH means a higher acidity, and thus a higher concentration of H<sup>+</sup> ions in the solution. These types of substances exhibit distinct properties: they taste sour and produce a piercing pain in contact with a wound (a lemon, for instance).<ref name=ucd>UC Davis Chem Wiki. (July 8, 2015). ''Acid/Base Basics'' [Online], Available: http://chemwiki.ucdavis.edu/Physical_Chemistry/Acids_and_Bases/Acid#Neutralization</ref>
In water, there are always some H<sup>+</sup> and OH<sup>-</sup> [[ion]]s in solution due to the self-ionization of water, but in acidic solutions, there will be more H<sup>+</sup> than OH<sup>-</sup>. More concentrated acids will have more H<sup>+</sup> in solution. Following the pH scale, a more acidic solution - one with more H<sup>+</sup> - will have a <em>lower</em> pH value.


When mixed with a [[base (chemistry)|base]], the pH of the new solution will balance out towards the neutral pH of 7, depending on the strength of the acid and base. This is known as neutralization.<ref name=ucd/>
Acids can react with [[base]]s in a [[neutralization]] reaction, where the H<sup>+</sup> from the acid reacts with the OH<sup>-</sup> of the base to produce a solution with a lower H<sup>+</sup> concentration - and a higher pH.


[[Acid rain]] is an environmental problem caused by [[pollution]] from energy use. Acid rain, acid snow and even acid fog, (all collectively referred to as just acid rain) forms when water interacts with [[pollutant]]s in the [[atmosphere]]. It has a lower pH than normal rain, and can be more than 25 times more acidic than clean rain. Visit the [[acid rain|acid rain page]] for more information.
[[Acid rain]] is an environmental problem, caused by acidic substances dissolving in rainwater. Often, these acidic substances are from [[pollution]] in the atmosphere. Acid rain, acid snow, and acid fog (all collectively referred to as 'acid rain') can all form from the interaction of water vapour, rain, or fog with acidic [[pollutant]]s. Acid rain can be quite damaging due to its adicity - clean rain has a typical pH of around 5.6, while acid rain has a typical pH of about 4.3: in other words, acid rain is usually about 10 times more acidic than clean rain. <ref name=EPA>United States Environmental Protection Agency. (July 11 2018). ''What is Acid Rain'' [online], Available: https://www.epa.gov/acidrain/what-acid-rain </ref> Visit the [[acid rain|acid rain page]] for more information.  


[[File:pHacid.png|800px|thumb|center|Figure 2. Various acids and bases on the pH scale.<ref>Adapted from Energy: Its use and the Environment -- R. A. Hinrichs and M. Kleinbach, "Acid Rain," in ''Energy: Its Use and the Environment'', 5th ed. Toronto, Ont. Canada: Brooks/Cole, 2006, ch.8, sec.C, pp.252-256</ref>]]
[[File:pHacid.png|800px|thumb|center|Figure 2. Various acids and bases on the pH scale.<ref>Adapted from Energy: Its use and the Environment -- R. A. Hinrichs and M. Kleinbach, "Acid Rain," in ''Energy: Its Use and the Environment'', 5th ed. Toronto, Ont. Canada: Brooks/Cole, 2006, ch.8, sec.C, pp.252-256</ref>]]
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==Uses==
==Uses==


Acids have many uses. They can be used to remove rust from [[metal]]s, as an [[electrolyte]] in a wet-cell [[battery]] (such as a car battery), in the chemical industry to produce many desired products, as additives to drinks or food to alter taste and act as a preservative (in soda for example), and occur naturally in fruits and vegetables.  
Acids occur naturally (for example in fruits and vegetables) and man-made acids are widely used in industry, for cleaning, and as food additives. For example, they can be used to remove [[oxidize|rust]] from [[metal]]s, as an [[electrolyte]] in a wet-cell [[battery]] (such as a car battery), in the chemical industry as an important component of production, and as additives to food and drink to alter taste and act as a preservative (e.g. in soda).


Acids are also important in the human body. They act to break down food, are used for [[protein]] synthesis, tissue repair, and pH balancing. Ascorbic acid (Vitamin C) is essential for the human body, as well as many other acids. The "A" in DNA and RNA stands for acid, and these are crucial [[molecule]]s for all life.  
Acids are also important in the human body. Stomach acid breaks down food in one of the first stages of digestion, and [[organic molecule|organic]] acids are used for [[protein]] synthesis, tissue repair, and pH balancing in tissues. Ascorbic acid (Vitamin C) is essential for the human body, as well as many other acids. The "A" in DNA and RNA stands for acid, and these are crucial [[molecule]]s for all life.
==Phet Simulation==
The [http://phet.colorado.edu/ University of Colorado] has graciously allowed us to use the following Phet simulation. Explore this simulation to see how the pH of acids and bases work.


To learn more about acids and bases please see [http://chemwiki.ucdavis.edu/Physical_Chemistry/Acids_and_Bases UC Davis's chem wiki].
<html>
<iframe src="https://phet.colorado.edu/sims/html/acid-base-solutions/latest/acid-base-solutions_en.html" width="800" height="600"></iframe>
</html>
 
==For Further Reading==
*[[Base]]
*[[The pH scale]]
*[[Chemical]]
*[[Water]]
*[[Acid rain]]
*[[Water cycle]]
*Or explore a [[Special:Random|random page]]
 
To learn more about acids and bases please see [https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid/Overview_of_Acids_and_Bases the Chemistry LibreText].
==References==
==References==
{{reflist}}
{{reflist}}
[[Category:Uploaded]]

Latest revision as of 00:03, 27 September 2021

Figure 1. Lemons are acidic, with a pH of around 2.[1]

An acid is any substance that will react with water to produce H+ [2] (H+ reacts in water to produce H3O+ - both can be treated as equivalent.) Generally, solutions of acid in water will have a pH less than 7.

In water, there are always some H+ and OH- ions in solution due to the self-ionization of water, but in acidic solutions, there will be more H+ than OH-. More concentrated acids will have more H+ in solution. Following the pH scale, a more acidic solution - one with more H+ - will have a lower pH value.

Acids can react with bases in a neutralization reaction, where the H+ from the acid reacts with the OH- of the base to produce a solution with a lower H+ concentration - and a higher pH.

Acid rain is an environmental problem, caused by acidic substances dissolving in rainwater. Often, these acidic substances are from pollution in the atmosphere. Acid rain, acid snow, and acid fog (all collectively referred to as 'acid rain') can all form from the interaction of water vapour, rain, or fog with acidic pollutants. Acid rain can be quite damaging due to its adicity - clean rain has a typical pH of around 5.6, while acid rain has a typical pH of about 4.3: in other words, acid rain is usually about 10 times more acidic than clean rain. [3] Visit the acid rain page for more information.

Figure 2. Various acids and bases on the pH scale.[4]

Uses

Acids occur naturally (for example in fruits and vegetables) and man-made acids are widely used in industry, for cleaning, and as food additives. For example, they can be used to remove rust from metals, as an electrolyte in a wet-cell battery (such as a car battery), in the chemical industry as an important component of production, and as additives to food and drink to alter taste and act as a preservative (e.g. in soda).

Acids are also important in the human body. Stomach acid breaks down food in one of the first stages of digestion, and organic acids are used for protein synthesis, tissue repair, and pH balancing in tissues. Ascorbic acid (Vitamin C) is essential for the human body, as well as many other acids. The "A" in DNA and RNA stands for acid, and these are crucial molecules for all life.

Phet Simulation

The University of Colorado has graciously allowed us to use the following Phet simulation. Explore this simulation to see how the pH of acids and bases work.

For Further Reading

To learn more about acids and bases please see the Chemistry LibreText.

References

  1. ↑ Wikimedia Commons [Online], Available: https://commons.wikimedia.org/wiki/File:Lemon.jpg
  2. ↑ Chemistry LibreTexts. (July 11 2018). Overview of Acids and Bases [online], Available: https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid/Overview_of_Acids_and_Bases
  3. ↑ United States Environmental Protection Agency. (July 11 2018). What is Acid Rain [online], Available: https://www.epa.gov/acidrain/what-acid-rain
  4. ↑ Adapted from Energy: Its use and the Environment -- R. A. Hinrichs and M. Kleinbach, "Acid Rain," in Energy: Its Use and the Environment, 5th ed. Toronto, Ont. Canada: Brooks/Cole, 2006, ch.8, sec.C, pp.252-256
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