Wednesday, April 13, 2011

Friday, 4/8/11, Acids and Bases

This is a late post.....Mon and Tue are below:

Acids and Bases, 4/8/11
1. Went over the properties of acids and bases.

2. Took a partner quiz on acids and bases.

3. Took notes.

Part 1- The Simulation
1. List the molecules and/or ions present in the solution of HCl.
-H+ Cl- H20
2.List the molecules and/or ions present in the solution of NaOH.
-Na+ OH- H2O
3. What is the purpose of the phenolphthalein (phth)?
-it is an indicator (base/ OH- turns pink)
4. Why doesnt the phenolphthalein change colors when it is first added to the cup?
-Acid + pht
5. What is the reaction that is happening when the NaOH is added to the cup?
-Neutralization reaction, NaOH + HCl produces NaCl + H2O
6. What has to be true for the phenolphthalein to turn pink?
- OH- > H+
first slight pink
4. Part 2 of the notes: We did a lab using the base NaOH and the acid HCl. In the lab we had to put 10drops of HCl into a paper cup with one drop of phth. Next we add 1 drop of NaOH into the cup and mix it around when we see the pink. We continued this procedure until the pink remained the color of the mixture. Here is my groups data:

Drops HCl (.40M) Drops NaOH (X M)
Trial 1 10 36
Trial 2 10 31
Trial 3 10 67
Trial 4 10 63

We then used the equation Macid x Drops acid = Mbase x Drops base to figure out the molarity of NaOH in each trial. Here are our results:
Trial 1- .11 Trial 2- .13
Trial 3- .06 Trial 4- .06
The average concentration of the NaOH was .18.
In our lab results we had deviant trials. You can disguard deviant trials however mention it.

Posted by Therese Snow at 8:21 PM 0 comments
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Labels: Acids and Bases, Snow

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