Acids and Bases

The last day of actual class at La Junta High School, and we did probably one of the most educational labs I have ever done.  In order to effectively understand Acids and Bases before the year ended, five of us, with the help of Mr. Ludwig, completed the Acid-Base Titration Lab.

Each solution is either determined as an acid or a base depending on it's pH level. If a solution has a pH level of 0-7 it's an acid. If it has a pH level of 7-14 it's a base. If the pH level remains at 7, it's neutral. An example of this would be water. There is a turning point in which the acid turns immediately to a base, and visa versa.
Looking at the difference between acids and bases:

Acids                                                              Neutral                                           Base
low pH                                                             water                                         high pH
bad?                                                                                                                   good?
H+                                                                                                                     OH-

The determining factor between acids and bases is not only dependent on the pH level but also on the amount of hydrogen and hydroxide in the solution. If there is more hydrogen in the solution the solution is an acid, whereas if there is more hydroxide it is a base.

The Experiment:

Our goal for this experiment was to get our solution to the turning point(equivalency point) where it turns from an acid to a base. We were attempting to graph this point on LoggerPro.

Steps:

1. We placed 10 mL of the HCL solution into the beaker along with 50 mL of water.

2. We placed a stirrer in the beaker and placed it on the magnetic stirrer so that it could stir the entire duration of the experiment.
3. We suspended a pH sensor that was connected to LoggerPro into the water in order to track our results. Also, in order to track the pH levels, Mr. Ludwig dropped in a few drops of pH indicator. We did this so that when the acid turned into a base, we would be able to tell immediately because the indicator would scream pink.

4. Using a 50mL buret filled with 0.1 M NaOH, we careful placed the NaOH solution into the distilled water and HCL solution, tracking the amount and pH level every 2 mL.

(because NaOH is a base and HCL is an acid, the solution in the beaker began as an acid. As we slowly poured NaOH into the solution, it was changing into a base.)

Once the solution turned pink, we knew it was fully transformed into a base.

Graph:

As determined by the graph, our experiment went very well as we did accomplish the "S graph" look. As the points on the graph climb, the acid slowly begins turning into a base as the pH level rises. The few dots on the graph that rise so abruptly are the equivalency points where the acid turns into a base, then slowly levels out as a base.

Through the graph and data we collected we were able to determine the concentration of NaOH in the beginning, an the volume of NaOH moles of NaOH, Moles of HCl, and the Concentration of HCL all at the equivalency point.
Concentration of NaOH at beginning: 0.1 M
Volume of NaOH at equivalency point: 15.51 mL or .01551 L
Moles of NaOH at equivalency point: .001551 mol
Moles of HCl at equivalency point: .001551 mol   (the moles of NaOH and the moles of HCl must be equal at the equivalency point.)
Concentration of HCl at equivalency point: .1551 mol/L (to calculate this, we divided the moles of HCl by .01)



In this lab I learned how easy it is for an acid to turn into a base, especially in this case. It only took a drop for the acid to turn pink(into a base). It was a lot of fun working as a class for this last lab. Each of us had a job to do and in this way we accomplished the lab to Mr. Ludwig's expectations. Success!! (:

Crystal Lab

With the extremely busy schedule everyone has had lately, it was no surprise that I missed almost all of the formation of my crystal. I was however involved in all of the process, but lacked many pictures, except the final result.

Here are the steps for the lab:
1. obtain distilled water and put it in a beaker.
2. we put the aluminum potassium sulfate in the distilled water and mixed until it was supersaturated.
3. When there were little crystals still in the bottom of the beaker after it is completely saturated, we put the beaker on the hotplate and repeated the process. The hotter the water is the more it is able to absorb so the aluminum potassium sulfate.
4. we kept adding aluminum potassium sulfate until the heated mixture was supersaturated as well.
5. we left the mixture to cool overnight.

We returned the next day to find that there were crystal seeds all over the beaker.

We then took the seed crystal and tied it to a string, then repeated the supersaturated process.

The next day that I actually returned to this class, my crystal was pretty big and my beaker was full of tiny crystals just hanging out at the bottom.

I learned a lot about how crystals can be formed by supersaturating the distilled water. I also learned that creating crystals takes a lot of time and patience as they have to sit and cool. It's interesting to see how quickly the crystals grew overnight though, as they started out with a seed crystal about this size:

They turned into multiple crystals about this size:

This is probably one of the coolest labs I have done in chemistry. Even though it was easy and time consuming, it had a cool result that all of us got to take home with us. I definitely feel like I learned some valuable information through this lab.

Different Types of Chemical Reactions

1. A+B = AB synthesis reaction
    N2+H2 = NH3

2. AB = A+B decomposition reaction

3. A+BC = B+AC  single replacement (bad prom)
    Zn +AgNO3 = Ag+Zn(NO3)2

4. AB+CD = CB+AD (double replacement)

5. C3H8+O2 = CO2 +H2O (combustion) - hardest to balance