Investigations of Buffers
CHM 116 Lab
Investigations of Buffers
I. Purpose
The purpose of this experiment was to get an understanding as to how to properly prepare chemical buffers. Also part of this experiment was to gauge the effectiveness of the buffers by measuring their pH levels in various titration solutions, using a pH meter.
II. Procedure
To start our experiment we had to prepare Buffer B, which was the .060 M Ammonia/Ammonium solution. Using 3.0 M ammonia, we had to calculate the proper volume of NH3 base by using the M1V1 equation. Calculation:
Using pipettes we measured out the needed volume and transferred it to an Erlenmeyer flask, which we eventually used to combine the solution.
We also had to calculate the grams of salt needed to make Buffer B. The salt we used was ammonium chloride (NH4Cl). The calculation below shows how we found the appropriate weight. Calculation:
We used a scooping utensil to collect the salt and used a weigh boat to hold and measure the mass. (The weight of the weigh boat was zeroed out prior to measuring the salt). Once we added the salt to the ammonia and completely mixed the solution, we pipetted 20 mL into a volumetric flask. Then we set up a titration system using 0.100M NaOH in the buret.
For the step-by-step procedure guidelines, refer to, “Investigations of Buffers. CHM 116 Spring 2013 Lab Manual, Grand Valley State University pages 49-56”
III. Data
Ammonia/Ammonium Buffer.
Table I. Titration of HCl in 5 Different Solutions Volume of HCl added (mL) | pH of Solution A | pH of solution B | pH of Solution C | pH of Solution D | pH of Solution E | 0.00 | 4.56 | 9.20 | 4.61 | 3.01 | 5.64 | 1.00 | | | 4.37 | | | 2.00 | 4.40 | 9.04 | 4.15 | 2.24 | 1.93 | 3.00 | | | 3.90 | | | 4.00 | 4.20 | 8.82 | 3.50 | 2.05 | 1.76 | 5.00 | | | 2.86 | | | 6.00 | 3.97 | 8.50 | 2.20 | 1.91 | 1.67 | 7.00 | | | 2.07 | | | 8.00 |
Investigations of Buffers
I. Purpose
The purpose of this experiment was to get an understanding as to how to properly prepare chemical buffers. Also part of this experiment was to gauge the effectiveness of the buffers by measuring their pH levels in various titration solutions, using a pH meter.
II. Procedure
To start our experiment we had to prepare Buffer B, which was the .060 M Ammonia/Ammonium solution. Using 3.0 M ammonia, we had to calculate the proper volume of NH3 base by using the M1V1 equation. Calculation:
Using pipettes we measured out the needed volume and transferred it to an Erlenmeyer flask, which we eventually used to combine the solution.
We also had to calculate the grams of salt needed to make Buffer B. The salt we used was ammonium chloride (NH4Cl). The calculation below shows how we found the appropriate weight. Calculation:
We used a scooping utensil to collect the salt and used a weigh boat to hold and measure the mass. (The weight of the weigh boat was zeroed out prior to measuring the salt). Once we added the salt to the ammonia and completely mixed the solution, we pipetted 20 mL into a volumetric flask. Then we set up a titration system using 0.100M NaOH in the buret.
For the step-by-step procedure guidelines, refer to, “Investigations of Buffers. CHM 116 Spring 2013 Lab Manual, Grand Valley State University pages 49-56”
III. Data
Ammonia/Ammonium Buffer.
Table I. Titration of HCl in 5 Different Solutions Volume of HCl added (mL) | pH of Solution A | pH of solution B | pH of Solution C | pH of Solution D | pH of Solution E | 0.00 | 4.56 | 9.20 | 4.61 | 3.01 | 5.64 | 1.00 | | | 4.37 | | | 2.00 | 4.40 | 9.04 | 4.15 | 2.24 | 1.93 | 3.00 | | | 3.90 | | | 4.00 | 4.20 | 8.82 | 3.50 | 2.05 | 1.76 | 5.00 | | | 2.86 | | | 6.00 | 3.97 | 8.50 | 2.20 | 1.91 | 1.67 | 7.00 | | | 2.07 | | | 8.00 |