Acid/ Base properties of an antimicrobial agent
Chem 253
Lab 1: Acid/Base Properties of an Antimicrobial Agent
09/03/13
Purpose The purpose was to determine the acid and base properties of the antimicrobial agent sodium benzoate. Theory Sodium has mainly been used in food processing to avoid growth of bacteria and harmful microorganisms. It is commonly used to preserve foods and beverages that have an acidic pH. Rather than benzoic acid, sodium benzoate is used because it is generally soluble in most aqueous solutions but benzoic acid is not.
Reaction Sodium benzoate mixed with water, dissociates into benzoate and sodium ions.
Hydrogen chloride, which is a gas, will exist in ionized form when combined with water to form hydrochloric acid.
Then when the two solutions are combined, H3O+ transfers electrons to benzoate ions, which act as the base to form benzoic acid as a solid precipitate.
The overall balanced equation is as follows.
Yield Calculations:
Sodium Benzoate:
Hydrochloric Acid:
Theoretical:
The theoretical yield of Benzoic Acid is 1.298g.
The actual yield of Benzoic Acid is 1.251g.
The percent yield of this experiment is:
Methods/Procedures
1) Weigh and tare a 50 mL beaker, then place about 1.5g of sodium benzoate into the beaker. Record the actual mass of sodium benzoate used.
2) Measure about 10 mL of distilled water with a graduated cylinder and pour it into the beaker with the sodium benzoate. Use a glass-stirring rod to dissolve the sodium benzoate in the water.
3) Measure about 4 mL of 3.0 M HCl and add it slowly, with stirring, to the sodium benzoate solution until the pH of the solution is 2. Use pH paper to test the solution each time by using your stirring rod to place a drop of the solution on the pH paper. Adding excess HCl to the solution will not affect yield of product.
4) To induce crystallization of product, cool the solution to 10 degrees Celsius or below. Place your 50 mL beaker in a large
Lab 1: Acid/Base Properties of an Antimicrobial Agent
09/03/13
Purpose The purpose was to determine the acid and base properties of the antimicrobial agent sodium benzoate. Theory Sodium has mainly been used in food processing to avoid growth of bacteria and harmful microorganisms. It is commonly used to preserve foods and beverages that have an acidic pH. Rather than benzoic acid, sodium benzoate is used because it is generally soluble in most aqueous solutions but benzoic acid is not.
Reaction Sodium benzoate mixed with water, dissociates into benzoate and sodium ions.
Hydrogen chloride, which is a gas, will exist in ionized form when combined with water to form hydrochloric acid.
Then when the two solutions are combined, H3O+ transfers electrons to benzoate ions, which act as the base to form benzoic acid as a solid precipitate.
The overall balanced equation is as follows.
Yield Calculations:
Sodium Benzoate:
Hydrochloric Acid:
Theoretical:
The theoretical yield of Benzoic Acid is 1.298g.
The actual yield of Benzoic Acid is 1.251g.
The percent yield of this experiment is:
Methods/Procedures
1) Weigh and tare a 50 mL beaker, then place about 1.5g of sodium benzoate into the beaker. Record the actual mass of sodium benzoate used.
2) Measure about 10 mL of distilled water with a graduated cylinder and pour it into the beaker with the sodium benzoate. Use a glass-stirring rod to dissolve the sodium benzoate in the water.
3) Measure about 4 mL of 3.0 M HCl and add it slowly, with stirring, to the sodium benzoate solution until the pH of the solution is 2. Use pH paper to test the solution each time by using your stirring rod to place a drop of the solution on the pH paper. Adding excess HCl to the solution will not affect yield of product.
4) To induce crystallization of product, cool the solution to 10 degrees Celsius or below. Place your 50 mL beaker in a large