https://teaching.ncl.ac.uk/bms/wiki/index.php?title=Special:Contributions/110054009&feed=atom&deletedOnly=&limit=50&target=110054009&topOnly=&year=&month=The School of Biomedical Sciences Wiki - User contributions [en]2020-02-19T07:56:37ZFrom The School of Biomedical Sciences WikiMediaWiki 1.17.0https://teaching.ncl.ac.uk/bms/wiki/index.php/WavelengthWavelength2012-10-22T11:24:39Z<p>110054009: </p>
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<div>Wavelength is a property of all waves. It is the distance between a point on one wave, and the same point on the next wave in the sequence. <br />
<br />
It is shown in calculations as the lambda symbol (λ), and is defined as λ= Wavespeed/Frequency <br />
<br />
Within the electromagnetic spectrum: radio waves have the longest wavelength but the&nbsp;lowest frequency; but gamma rays have the shortest wavelength and the highest frequency. All other electromagnetic waves are found between these two extremes of the spectrum. <br />
<br />
Within [[School_of_Biomedical_Sciences_Wiki|Biomedical Sciences]] wavelength is usually referring to light, and is given the units of nanometres (nm). It is frequently used within&nbsp;[[Spectrophotometry|spectrophotometry]] practicals, as certain proteins and [[Compound|compounds]] are identified by their absorbance of light at specific wavelengths.</div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/WavelengthWavelength2012-10-22T11:21:10Z<p>110054009: Created page with "Wavelength is a property of all waves. It is the distance between a point on one wave, and the same point on the next wave in the sequence. It is shown in calculations as the l..."</p>
<hr />
<div>Wavelength is a property of all waves. It is the distance between a point on one wave, and the same point on the next wave in the sequence. <br />
<br />
It is shown in calculations as the lambda symbol (λ), and is defined as λ= Wavespeed/Frequency <br />
<br />
Within the electromagnetic spectrum: radio waves have the longest wavelength but the&nbsp;lowest frequency; but gamma rays have the shortest wavelength and the highest frequency. All other electromagnetic waves are found between these two extremes of the spectrum. <br />
<br />
Within Biomedical Sciences wavelength is usually referring to light, and is given the units of nanometres (nm). It is frequently used within&nbsp;spectrophotometry practicals, as certain proteins and compounds are identified by their absorbance of light at specific wavelengths.</div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/PHPH2011-12-01T23:16:57Z<p>110054009: </p>
<hr />
<div>The negative [[Logarithm|logarithm]] of the hydrogen ion concentration, the pH, is expressed as follows: <br />
<br />
pH = -log<sub>10</sub> [H<sup>+</sup>] <br />
<br />
The pH scale is a measure of hydrogen [[Ion|ion]] concentration that eliminates dealing with large powers of 10 and compresses a large range of concentrations onto a more convenient scale, between 1 and 14 as show in the figure below: <br />
<br />
[[Image:PH.png]]<br> <br />
<br />
=== Acid Dissociation<br> ===<br />
<br />
Strong [[Acid|acids]] are considered to be completely dissociated into [[Ion|ions]] in dilute solutions. However, weak [[Acid|acids]] (or [[Base|bases]]) are only partially dissociated in solution, and thus an [[Equilibrium|equilibrium]] is established between the [[Ion|ions]] and the undissociated [[Molecules|molecules]].<br> <br />
<br />
This equilibrium can be represented by the equation: <br> <br />
<br />
[HA]&lt;=&gt;[H<sup>+</sup>]+[A<sup>-</sup>]. <br> <br />
<br />
Where: [HA] is the [[Concentration|concentration]] of undissociated molecules; [H+] is the concentration of hydrogen ions; and [A-] is the concentration of the conjugate [[Base|base]].<br> <br />
<br />
This equation can be rearranged to give a K<sub>a</sub> value, which is a measure of how strong an [[Acid|acid]] is. <br />
<br />
K<sub>a</sub>= [H<sup>+</sup>][A<sup>-</sup>]/[HA] <br />
<br />
Stronger acids will dissociate more and will have a higher K<sub>a</sub> value.<ref>Elliot WH &amp;amp;amp; Elliot DC, 2009, Biochemistry and Molecular Biology p.38; Oxford</ref> <br />
<br />
Use of K<sub>a</sub> values is not very useful, as the differences in dissociation are massive between strong and weak acids, and the values calculated can vary by many orders of magnitude. As is done with the pH scale, we take the negative log of the K<sub>a</sub> value to give the pK<sub>a</sub> value.<ref>Elliot WH &amp;amp;amp; Elliot DC, 2009, Biochemistry and Molecular Biology p.39; Oxford</ref> <br />
<br />
pK<sub>a</sub>=-log<sub>10</sub>K<sub>a</sub> <br />
<br />
When: pK<sub>a</sub>=pH; the [[Compound|compound]] is said to be at it's equivalence point, as the [[Concentration|concentration]] of H+ is equal to the concentration of HA. <br />
<br />
=== References ===<br />
<br />
<references /></div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/PHPH2011-12-01T23:12:25Z<p>110054009: </p>
<hr />
<div>The negative [[Logarithm|logarithm]] of the hydrogen ion concentration, the pH, is expressed as follows: <br />
<br />
pH = -log<sub>10</sub> [H<sup>+</sup>] <br />
<br />
The pH scale is a measure of hydrogen [[Ion|ion]] concentration that eliminates dealing with large powers of 10 and compresses a large range of concentrations onto a more convenient scale, between 1 and 14 as show in the figure below: <br />
<br />
[[Image:PH.png]]<br> <br />
<br />
=== Acid Dissociation<br> ===<br />
<br />
Strong [[Acid|acids]] are considered to be completely dissociated into [[Ion|ions]] in dilute solutions. However, weak [[Acid|acids]] (or [[Base|bases]]) are only partially dissociated in solution, and thus an [[Equilibrium|equilibrium]] is established between the [[Ion|ions]] and the undissociated [[Molecules|molecules]].<br> <br />
<br />
This equilibrium can be represented by the equation: <br> <br />
<br />
[HA]&lt;=&gt;[H<sup>+</sup>]+[A<sup>-</sup>]. <br> <br />
<br />
Where: [HA] is the concentration of undissociated molecules; [H+] is the concentration of hydrogen ions; and [A-] is the concentration of the conjugate base.<br> <br />
<br />
This equation can be rearranged to give a K<sub>a</sub> value, which is a measure of how strong an acid is. <br />
<br />
K<sub>a</sub>= [H<sup>+</sup>][A<sup>-</sup>]/[HA] <br />
<br />
Stronger acids will dissociate more and will have a higher K<sub>a</sub> value.<ref>Elliot WH &amp;amp; Elliot DC, 2009, Biochemistry and Molecular Biology p.38; Oxford</ref><br />
<br />
Use of K<sub>a</sub> values is not very useful, as the differences in dissociation are massive between strong and weak acids, and the values calculated can vary by many orders of magnitude. As is done with the pH scale, we take the negative log of the K<sub>a</sub> value to give the pK<sub>a</sub> value.<ref>Elliot WH &amp;amp; Elliot DC, 2009, Biochemistry and Molecular Biology p.39; Oxford</ref><br />
<br />
pK<sub>a</sub>=-log<sub>10</sub>K<sub>a</sub><br />
<br />
When: pK<sub>a</sub>=pH; the compound is said to be at it's equivalence point, as the concentration of H+ is equal to the concentration of HA.<br />
<br />
=== References ===<br />
<br />
<references /></div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/PHPH2011-12-01T22:52:34Z<p>110054009: </p>
<hr />
<div>The negative [[Logarithm|logarithm]] of the hydrogen ion concentration, the pH, is expressed as follows: <br />
<br />
pH = -log<sub>10</sub> [H<sup>+</sup>] <br />
<br />
The pH scale is a measure of hydrogen [[Ion|ion]] concentration that eliminates dealing with large powers of 10 and compresses a large range of concentrations onto a more convenient scale, between 1 and 14 as show in the figure below: <br />
<br />
[[Image:PH.png]]<br> <br />
<br />
=== Acid Dissociation<br> ===<br />
<br />
Strong [[Acid|acids]] are considered to be completely dissociated into [[Ion|ions]] in dilute solutions. However, weak [[Acid|acids]] (or [[Base|bases]]) are only partially dissociated in solution, and thus an [[Equilibrium|equilibrium]] is established between the [[Ion|ions]] and the undissociated [[Molecules|molecules]].<br> <br />
<br />
This equilibrium can be represented by the equation: <br> <br />
<br />
[HA]&lt;=&gt;[H<sup>+</sup>]+[A<sup>-</sup>]. <br> <br />
<br />
Where: [HA] is the concentration of undissociated molecules; [H+] is the concentration of hydrogen ions; and [A-] is the concentration of the conjugate base.<br> <br />
<br />
This equation can be rearranged to give a K<sub>a</sub> value, which is a measure of how strong an acid is. <br />
<br />
K<sup>a</sup>= [H<sup>+</sup>][A<sup>-</sup>]/[HA] <br />
<br />
Stronger acids will dissociate more and will have a higher K<sub>a</sub> value.<ref>Elliot WH &amp; Elliot DC, 2009, Biochemistry and Molecular Biology; Oxford</ref> <br />
<br />
=== ===<br />
<br />
=== References ===<br />
<br />
<references /></div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/PHPH2011-12-01T22:51:36Z<p>110054009: </p>
<hr />
<div>The negative [[Logarithm|logarithm]] of the hydrogen ion concentration, the pH, is expressed as follows: <br />
<br />
pH = -log<sub>10</sub> [H<sup>+</sup>] <br />
<br />
The pH scale is a measure of hydrogen [[Ion|ion]] concentration that eliminates dealing with large powers of 10 and compresses a large range of concentrations onto a more convenient scale, between 1 and 14 as show in the figure below: <br />
<br />
[[Image:PH.png]]<br> <br />
<br />
=== Acid Dissociation<br> ===<br />
<br />
Strong [[Acid|acids]] are considered to be completely dissociated into [[Ion|ions]] in dilute solutions. However, weak [[Acid|acids]] (or [[Base|bases]]) are only partially dissociated in solution, and thus an [[Equilibrium|equilibrium]] is established between the [[Ion|ions]] and the undissociated [[Molecules|molecules]].<br> <br />
<br />
This equilibrium can be represented by the equation: <br> <br />
<br />
[HA]&lt;=&gt;[H<sup>+</sup>]+[A<sup>-</sup>]. <br> <br />
<br />
Where: [HA] is the concentration of undissociated molecules; [H+] is the concentration of hydrogen ions; and [A-] is the concentration of the conjugate base.<br> <br />
<br />
This equation can be rearranged to give a K<sub>a</sub> value, which is a measure of how strong an acid is. <br />
<br />
K<sup>a</sup>= [H<sup>+</sup>][A<sup>-</sup>]/[HA] <br />
<br />
Stronger acids will dissociate more and will have a higher K<sub>a</sub> value.<ref>Elliot WH &amp;amp;amp;amp;amp; Elliot DC, 2009, Biochemistry and Molecular Biology; Oxford</ref> <br />
<br />
=== ===<br />
<br />
=== References ===<br />
<br />
<references /></div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/PHPH2011-12-01T22:48:31Z<p>110054009: </p>
<hr />
<div>The negative [[Logarithm|logarithm]] of the hydrogen ion concentration, the pH, is expressed as follows: <br />
<br />
pH = -log<sub>10</sub> [H<sup>+</sup>] <br />
<br />
The pH scale is a measure of hydrogen [[Ion|ion]] concentration that eliminates dealing with large powers of 10 and compresses a large range of concentrations onto a more convenient scale, between 1 and 14 as show in the figure below: <br />
<br />
[[Image:PH.png]]<br> <br />
<br />
=== Acid Dissociation<br> ===<br />
<br />
Strong [[Acid|acids]] are considered to be completely dissociated into [[Ion|ions]] in dilute solutions. However, weak [[Acid|acids]] (or [[Base|bases]]) are only partially dissociated in solution, and thus an [[Equilibrium|equilibrium]] is established between the [[Ion|ions]] and the undissociated [[Molecules|molecules]].<br> <br />
<br />
This equilibrium can be represented by the equation: <br> <br />
<br />
[HA]&lt;=&gt;[H<sup>+</sup>]+[A<sup>-</sup>]. <br> <br />
<br />
Where: [HA] is the concentration of undissociated molecules; [H+] is the concentration of hydrogen ions; and [A-] is the concentration of the conjugate base.<br> <br />
<br />
This equation can be rearranged to give a K<sub>a</sub> value, which is a measure of how strong an acid is. <br />
<br />
K<sup>a</sup>= [H<sup>+</sup>][A<sup>-</sup>]/[HA] <br />
<br />
Stronger acids will dissociate more and will have a higher K<sub>a</sub> value.<ref>Elliot WH &amp;amp;amp;amp; Elliot DC, 2009, Biochemistry and Molecular Biology; Oxford</ref></div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/PHPH2011-12-01T22:46:38Z<p>110054009: </p>
<hr />
<div>&nbsp;The negative [[Logarithm|logarithm]] of the hydrogen ion concentration, the pH, is expressed as follows: <br />
<br />
pH = -log<sub>10</sub> [H<sup>+</sup>] <br />
<br />
The pH scale is a measure of hydrogen [[Ion|ion]] concentration that eliminates dealing with large powers of 10 and compresses a large range of concentrations onto a more convenient scale, between 1 and 14 as show in the figure below: <br />
<br />
[[Image:PH.png]]<br> <br />
<br />
=== Acid Dissociation<br> ===<br />
<br />
Strong [[Acid|acids]] are considered to be completely dissociated into [[Ion|ions]] in dilute solutions. However, weak [[Acid|acids]] (or [[Base|bases]]) are only partially dissociated in solution, and thus an [[Equilibrium|equilibrium]] is established between the [[Ion|ions]] and the undissociated [[Molecules|molecules]].<br> <br />
<br />
This equilibrium can be represented by the equation: <br> <br />
<br />
[HA]&lt;=&gt;[H<sup>+</sup>]+[A<sup>-</sup>]. <br> <br />
<br />
Where: [HA] is the concentration of undissociated molecules; [H+] is the concentration of hydrogen ions; and [A-] is the concentration of the conjugate base.<br> <br />
<br />
This equation can be rearranged to give a K<sub>a</sub> value, which is a measure of how strong an acid is. <br />
<br />
K<sup>a</sup>= [H<sup>+</sup>][A<sup>-</sup>]/[HA] <br />
<br />
Stronger acids will dissociate more and will have a higher K<sub>a</sub> value.<ref>Elliot WH &amp;amp;amp; Elliot DC, 2009, Biochemistry and Molecular Biology; Oxford</ref></div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/PHPH2011-12-01T22:45:40Z<p>110054009: </p>
<hr />
<div>&nbsp;The negative [[Logarithm|logarithm]] of the hydrogen ion concentration, the pH, is expressed as follows: <br />
<br />
pH = -log<sub>10</sub> [H<sup>+</sup>] <br />
<br />
The pH scale is a measure of hydrogen [[Ion|ion]] concentration that eliminates dealing with large powers of 10 and compresses a large range of concentrations onto a more convenient scale, between 1 and 14 as show in the figure below: <br />
<br />
[[Image:PH.png]]<br> <br />
<br />
=== Acid Dissociation<br> ===<br />
<br />
Strong [[Acid|acids]] are considered to be completely dissociated into [[Ion|ions]] in dilute solutions. However, weak [[Acid|acids]] (or [[Base|bases]]) are only partially dissociated in solution, and thus an [[Equilibrium|equilibrium]] is established between the [[Ion|ions]] and the undissociated [[Molecules|molecules]].<br><br />
<br />
This equilibrium can be represented by the equation: <br><br />
<br />
[HA]&lt;=&gt;[H<sup>+</sup>]+[A<sup>-</sup>]. <br><br />
<br />
Where: [HA] is the concentration of undissociated molecules; [H+] is the concentration of hydrogen ions; and [A-] is the concentration of the conjugate base.<br><br />
<br />
This equation can be rearranged to give a K<sub>a</sub> value, which is a measure of how strong an acid is. <br />
<br />
K<sup>a</sup>= [H<sup>+</sup>][A<sup>-</sup>]/[HA]<br />
<br />
Stronger acids will dissociate more and will have a higher K<sub>a</sub> value.<ref>Elliot WH &amp; Elliot DC, 2009, Biochemistry and Molecular Biology; Oxford</ref></div>110054009https://teaching.ncl.ac.uk/bms/wiki/index.php/VirusVirus2011-12-01T20:47:36Z<p>110054009: </p>
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<div>A virus is a non-living thing.</div>110054009