Sunday, May 15, 2011

Acids and Bases

To finish off chem class we have been working with acids and bases. We have done two labs now that deal with this concept. In one lab we had a variety of common acids and bases that we see around in our daily lives. These included things such as Pine Cleaner, Tums, orange juice, etc. We tested these common household items by putting a small amount in a baggy with some red cabbage juice. This juice turned the acids and bases colors so they were easy to identify. We used this indicator to tell us how acidic or basic.
The other lab that we preformed was a bit more complex. In this lab we started out with a beaker of acidic solution on a Bunsen burner with a constant stirring magnet inside of it. Above this acidic solution we have a temperature probe that hangs down just far enough into the water that it picks up accurate readings and there is also a buret hanging right above the acidic solution containing basic solution. First in this lab we put a few drops of phenolphalien in our acidic solution for a color change so we could see the process happening. We constantly released some of the base into the acid until our data showed a drastic change in data. This giant data change showed the number at which the acid changed to a base and it gave us the measurement for the unknown concentration of the acid.
                     This is what our data looked like:
These two labs both showed us the basics of acids and bases. To summarize all we have learned up really quickly its as simple as this:
1) pH scale: 1-14, 7 distilled water = neutral,  1-6 acid, 7 neutral, 8-14 base
2) water is considered neutral because its H+ and OH- are equal
3) when there is more H+ the solution will be an acid such as HCl
4) when there is more OH- the solution will be a base such as NaOH
5) red cabbage and phenolphthalein are examples of indicators that show evidence by different shades of color, whereas a temp probe is an actual measurement of hydrogen ions with real data evidence.
6) acids = red, pink      neutral = yellow, purple(if cabbage juice)       base = blue, green
7) moles/L = molarity or 1 X 10^-7 moles/L <-- neutral equation to find any pH take the exponent without the negative sign and that will give you your answer
8) acids and bases make up a lot of the common things we see around us such as food and cleaners. some can be dangerous, but for the most part if you use them correctly they are very good things to have around

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