Acid Base Titration Lab

Titration Lab

Materials:
-Mac
-Vernier Computer Interface
-LoggerPro
-Vernier pH senso
-HCL Solution, unknown Concentration
-0.100 M NaOH Solution
-Magnetic Stirrer
-Stirring Bar
-Wash Bottle
-50-mL buret
-Ring Stand
-2 Utility Clamps
-10-mL pipet
-Pipet Pump
-250-mL beaker
-Distilled water

The picture below is the whole reason why we did this experiment. As we slowly added NaOH (a base) to hydrochloric acid (a acid) We watched to see the exact point when the acid changed to a base. As you can see from this graph and the list of levels to the left, it was after we added about 16 mL of NaOH. It was really interesting to watch the sudden change in pH levels that occurred after we added just the right amount of base.
        In this lab the equivalence point was 16 mL because that was the point that the pH level started to rise to a point that would classify the solution as a base instead of an acid.
Mr. Ludwig introduced me to this little equation to help me discover the concentration of the acid.
It is:
M1V1=M2V2
Basically what that means is that the concentration of the base (NaOH) multiplied by the Volume of NaOH that we slowly added is equal to the concentration of the acid (HCL)  multiplied by the Volume of the Acid we used.
After doing the math I came up with 1.6x10^-5 for the concentration of the acid.

Crystal Lab and Finding Concentrations

These last couple of weeks we have done A LOT of labs in Chemistry. First is the Crystal Lab...this was a fun lab because we got to do a lot of trial and error in making perfect crystals.

Click Here for my Glog over the Crystal Lab

The second lab I am including in this post is the Concentration Lab. Also called the Beer's Lab.

What we used:
Macbook
Vernier Computer Interface
Logger Pro
Vernier Colorimeter
One cuvette
Test Tubes
Tissues
Stirring Rod
30 mL of .40 M NiSO4
5 mL of NiSO4 Unknown solution
Pipet and Pipet Pump
Distilled Water
Test tube Rack
Beakers

What we did:
1. We set up our work station and pulled up the correct LoggerPro file. We set out the .40 M NiSO4 stock solution and the distilled water.
2. We set out the test tubes and used the pipet to add 2, 4, 6, and 8 mL of the stock solution into test tubes 1-4. Then we used the pipet to add 8, 6, 4, and 2 mL of distilled water into test tubes 1-4.
We kept the rest of the stock material in the beaker.
3. Next we calibrated the Colorimeter. We filled a cuvette 3/4 of the way full with distilled water. We put the cuvette into the colorimeter and used LoggerPro.
          -We chose Calibrate from the Experiment Menu. Selected One Point Calibration and then set the Colorimeter to the 0% T Position, typed 0 in the edit box and clicked "keep". We did the same thing at the Red LED position and typed 100 in the edit box and clicked "keep".
4. Then we clicked "Collect" on the graph and emptied the cuvette and added the solution from test tube 1 and put it into the Colorimeter. We waited for the absorbance valued to stabilize and then clicked "keep" and then typed .080. in the edit box.
5. We repeated Step 4 for Test Tubes 2-4. In the edit box for Test Tube 2 we typed .16, for test tube 3 we typed .24 and for test tube 4 we typed .32. We then recorded the stock solution. After we finished this we clicked "stop".
6. We used the Linear Regression button to see if there was a direct relationship between absorbance and concentration.
7. After that we used a cuvette and the colorimeter to record the unknown NiSO4 solution. We then recorded he absorbance value of the solution in this chart:

Why we did it:

This a picture of the Graph from the experiment. We used Interpolate from the Analyze menu to find the Concentration of the unknown solution by looking at the absorbance.
The Concentration of the unknown substance was .217 mol/L.