Irresistible Lab Report Chem 109
Abstract
A buffer is a solution that resists changes in pH when H+, OH-, or H20 is added. By using standard lab equipment, a lab pro diagnostic tool, and acidic and basic solutions, the pH can be found. By recording the pH while adding a base or an acid gradually to a buffer solution you can find the capacity of each buffer to resist drastic changes in pH. The best buffers will keep a solution from becoming either too acidic or basic with the addition of a strong base or acid.
Introduction
The objective of the Irresistible lab is to determine the capacity of each solution (unbuffered and buffered both) and how much they resist changes to pH. This is accomplished by having ten graduated beakers: two containing pure water, two with .1 M Sodium Chloride, two with 1 gram of solid sodium acetate dissolved in acetic acid, two with 5 grams of solid sodium acetate dissolved in acetic acid, and two with 10 grams of solid sodium acetate dissolved in acetic acid. These are split into two groups of five containing one of each solution. The pH of each solution is then measured and a pipette is used to distribute 1 mL of HCl, a strong acid, at a time to each solution in the first set, with the pH being measured and recorded until a drastic change is recorded. The procedure will be repeated with the other set of solutions using NaOH, a strong base.
I would predict that the pure water and sodium chloride solutions would not have a very strong buffering capacity and therefore would almost immediately drop or raise the pH level depending on whether a base or acid was added. As far as the mixture of sodium acetate and acetic acid, I would predict that they would be a better buffer than the previous solutions. There are varying amounts of sodium acetate, but I don’t predict that they will have much different results as far as buffering solutions goes. This is because they all have the same amount of acetic acid, which will act as the main buffer. I predict that this will be the
A buffer is a solution that resists changes in pH when H+, OH-, or H20 is added. By using standard lab equipment, a lab pro diagnostic tool, and acidic and basic solutions, the pH can be found. By recording the pH while adding a base or an acid gradually to a buffer solution you can find the capacity of each buffer to resist drastic changes in pH. The best buffers will keep a solution from becoming either too acidic or basic with the addition of a strong base or acid.
Introduction
The objective of the Irresistible lab is to determine the capacity of each solution (unbuffered and buffered both) and how much they resist changes to pH. This is accomplished by having ten graduated beakers: two containing pure water, two with .1 M Sodium Chloride, two with 1 gram of solid sodium acetate dissolved in acetic acid, two with 5 grams of solid sodium acetate dissolved in acetic acid, and two with 10 grams of solid sodium acetate dissolved in acetic acid. These are split into two groups of five containing one of each solution. The pH of each solution is then measured and a pipette is used to distribute 1 mL of HCl, a strong acid, at a time to each solution in the first set, with the pH being measured and recorded until a drastic change is recorded. The procedure will be repeated with the other set of solutions using NaOH, a strong base.
I would predict that the pure water and sodium chloride solutions would not have a very strong buffering capacity and therefore would almost immediately drop or raise the pH level depending on whether a base or acid was added. As far as the mixture of sodium acetate and acetic acid, I would predict that they would be a better buffer than the previous solutions. There are varying amounts of sodium acetate, but I don’t predict that they will have much different results as far as buffering solutions goes. This is because they all have the same amount of acetic acid, which will act as the main buffer. I predict that this will be the
References: Kautz, J., D. Kinnan, and C. McLaughlin. 2011-2012. Chemistry 110 Laboratory Manual “Taking things apart… Putting things together”. Plymouth, MI: Hayden-McNeil Publishing. Gilbert, T.R., R.V. Kriss, N. Foster, G. Davies. 2004. Chemistry The Science In Context. New York, NY: W. W. Norton & Company