Base: A Base is the opposite of an acid. Acids donate hydronium ions, taste bitter, and are corrosive.
This data can be found from PDF 19.



pH ,,Scale: Non-linear scale used to tell the alkalinity or acidity of a substance. Substances with a pH level of 7 are neutral. Ones with a pH level below 7 are acidic. Ones with a pH above 7 are basic. pH stands for "potential of Hydrogen" because an acid's strength is based on its ability to release Hydronium ions. It is also very good with chicken noodle soup.


Video By Thomas G. Reagan A. and Eric E.

litmus_paper.jpg
Figures 1 and 2. Litmus Paper Demonstration

"Acids and Bases." GCSE Science Chemical Reactions. BBC. 22 Feb 2007 <http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel/chemicalreactions/makingsaltsrev2.shtml>.


external image waters_ph_chart.jpg

Figure 3. pH scale with examples of environmental effects.

external image litmus.jpe
Figure 4. Red and Blue Litmus Paper
"Science Lab Techniques ." Science Lab Techniques . 22 Feb 2007 <oldwww.mtlsd.org/senior/science/JPtachcinski/...>.

Do you know what color blue l.p. turns in an acid? in a base? Do you know what color red l.p. turns in an acid? in a base? What happens in both of these situations if the solution is neutral? - JT

acidbase.jpg
Figure 5. Unused Red and Blue Litmus Paper
"The Science Fair." The Science Fair. 1999. 22 Feb 2007 <www.thesciencefair.com/Merchant2/merchant.mvc...>. "




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Figure 6. Two Containers of Litmus Paper
"Litmus Paper." BK's School House. 2007. BK's School House. 22 Feb 2007 <bksschoolhouse.com/shop.php?pid=13513>.




-Data:
Name
Blue Litmus Paper Results
Red Litmus Paper Results
CA Water
No Change
No Change
Vinegar
Turns Red
No Change
Soap
No Change
No Change
Household Cleaner
No Change
Turns Blue
Pineapple Orange Juice
Turns Red
No Change
Milk
No Change
Turns Blue
Diet Coke
Turns Red
No Change
Ammonia
No Change
Turns Blue
Lemon Juice
Turns Red
No Change
Milk of Magnesia
No Change
Turns Blue
Table 1. pH Litmus paper data, when tested with ten common substances.


-Analysis:

Though using litmus paper is an effective method to find whether a substance is basic or acidic, the paper sometimes is not correct. For example, the pH probe results revealed that milk had a pH of 6.97, barely making milk acidic. Since the pH was so close to neutral, the red litmus paper turned blue, so according to the litmus paper, milk was basic. Litmus paper is not as precise as a pH probe, but can be used for easy and quick results.

- How precise it litmus paper? -JT

How Does Litmus Paper Work?

Red litmus paper is such a color because the molecule making it up is an un-ionized molecule that emits mainly only the red spectrum and absorbs energy from all other frequencies. The blue litmus paper is made up of ionized molexules that emit only blue. When the blue litmus paper turns red, an acid has dropped hydrogen ions (protons) onto the paper, stabilizing the ions, reducing the vibration frequency, and then the area of paper absorbs a different spectrum, based upon the amount of ions dropped onto it. When the red litmus paper turns blue, the opposite reaction occurs, it gave protons and destabilized, increasing vibration, lowering wavelength. When in contact with a base, the blue paper stays blue and when in contact with an acid, the red paper stays red. This is because the complementary spectrum is already being absorbed as it is still out of phase with the complementary spectrum, so nothing changes. Also, when the litmus paper comes in touch with pure deionized water, there is no change, because the water doesn't have any ions to take from or give to the paper.

Logan, R.H.. "What is the chemical reaction that occurs when litmus paper changes color?." members.aol.com. 4 April, 1997. aol.com. 23 Feb 2007 http://members.aol.com/profchm/indicators.html.

-What is litmus paper?:

Litmus dye is a natural pH indicator.

Litmus paper is a small strip of paper that has dyes in it. When it touches a base or a dye then the litmus paper changes colors depending on if it is a bases of if it is an acid. If a litmus paper is exposed to an acid it either changes it a pink or red color. If a strip of litmus paper touches a base then the paper changes to a shade of blue.

Litmus is a dye made from species of lichens (fungi). A commonly used lichen is roccella tinctoria. Paper dyed with this substance is called litmus paper, and it is used to test the pH of a substance. It is used as a very rough acid-base indicator, (not as precise as a pH probe) though give fast and easy test results. Red litmus paper turns blue when exposed to a base while blue litmus paper turns red when the exposed to an acid. Neutral substances do not change the color of litmus paper.

-"litmus." The Columbia Electronic Encyclopedia, Sixth Edition. Columbia University Press., 2003. Answers.com 22 Feb. 2007. http://www.answers.com/topic/litmus
-Delisle, Sandy. "Litmus Paper." Answers.com. Answers Corporation. 22 Feb 2007 <http://www.answers.com/topic/litmus-paper>.
-"Litmus test (chemistry)." Wikipedia, The Free Encyclopedia. 22 Feb 2007, 04:47 UTC. Wikimedia Foundation, Inc. 22 Feb 2007 <http://en.wikipedia.org/w/index.php?title=Litmus_test_%28chemistry%29&oldid=109998375>.
"Glossary-Litmus Paper." Glossary. Glossary. 22 Feb 2007 <http://www.chemheritage.org/EducationalServices/pharm/glossary/litmus.htm>.
"Litmus Paper." The Free Dictionary. Farlex. 22 Feb 2007 <http://www.thefreedictionary.com/litmus+paper>.





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