lab 1 biochem procedure

What safety equipment must be worn at all times during the experiment?

Chemical-splash safety goggles.

What are the materials needed for the experiment?

Benzoic acid, sucrose, urea, denatured alcohol, P8 filter paper, Merck Index.

What is the first step in the separation of benzoic acid/sucrose mixtures?

Put on chemical-splash safety goggles.

How much benzoic acid is used in the experiment?

0.3 grams.

What should you do if benzoic acid comes into contact with your skin?

Wash with soap and water.

What is the purpose of zeroing (taring) the balance before weighing substances?

To ensure accurate measurement of the substance's mass without including the weight of the weighing paper.

What should you do after adding distilled water to the benzoic acid and sucrose mixture?

Insert a clean rubber stopper, shake the test tube for 1 minute, and place it in the test tube rack.

What is the predominant solid to be identified after filtering test tube #1?

Either sucrose or benzoic acid, determined by comparing its appearance with pure samples.

What is the procedure for preparing the second mixture of benzoic acid and sucrose?

Add 0.3 grams of each to a clean test tube, then add 10 mL of denatured alcohol and shake.

What is the next step after constructing a gravity filtering apparatus?

Add the contents of test tube #1 to the funnel.

What is the first step in the separation of benzoic acid/urea mixtures?

Describe and compare the appearance of benzoic acid and urea crystals.

What is the procedure for preparing the mixture of benzoic acid and urea in test tube #3?

Add 0.3 grams of benzoic acid and 0.3 grams of urea, then add 10 mL of distilled water.

What should be done with the contents of test tube #4 after adding denatured alcohol?

Shake the test tube for 1 minute and place it in the test tube rack.

What is the purpose of looking up solubility values in the Merck Index?

To record the solubility of benzoic acid, sucrose, and urea in water and alcohol.

What should you do with the solubility values found in the Merck Index?

Convert them to grams per milliliter if necessary and record your calculations.

What is the final step after completing the experiment?

Clean all glassware and equipment, return everything to its proper location, and wash your hands.

What chemical must be stored and dispensed under a fume hood during the experiment?

Denatured alcohol.

How should the rubber stopper be inserted into the test tube?

Press down gently to ensure a snug fit without breaking the test tube.

How long should you shake the test tubes after adding liquids?

For 1 minute.

What is the significance of comparing the appearance of crystals?

To distinguish between different substances during the experiment.

What is the mass of sucrose to be added to the mixture?

0.3 grams.

What should be done after filtering the contents of test tube #3?

Identify the predominant solid left on the filter paper.

What type of flask is used in the gravity filtering apparatus?

A 125-mL Erlenmeyer flask.

What is the purpose of using weighing paper?

To accurately weigh solid substances without contamination.

What is the first step before weighing benzoic acid on a balance?

Zero (tare) the balance with a piece of weighing paper.

What should you record after weighing benzoic acid?

The mass of the benzoic acid sample.

What is the procedure for weighing sucrose?

Zero (tare) the balance with weighing paper before adding sucrose.

What should you indicate after weighing sucrose?

The mass of the sucrose sample.

What is the volume of distilled water added in Test Tube #1?

10 mL.

What observation should be made after filtering the mixture in Test Tube #1?

Identify if the solid on the filter paper is mostly benzoic acid, sucrose, or if there is no solid.

What is the purpose of denatured alcohol in Test Tube #2?

To observe the solubility of benzoic acid and sucrose.

What should be recorded after weighing urea in Test Tube #3?

The mass of the urea sample.

What should you observe after filtering the mixture in Test Tube #3?

Determine if the solid is mostly benzoic acid, urea, or if there is no solid.

What is the significance of the Merck Index in this experiment?

To look up the solubility of benzoic acid, sucrose, and urea in water and alcohol.

What units should solubility values be expressed in?

Grams per milliliter.

How do you convert solubility values to grams per milliliter?

Divide the numerator by the denominator if necessary.

What is the question regarding the least soluble compound in water?

Which compound is the least soluble in water: Sucrose, Benzoic acid, or Urea?

What is the question regarding the least soluble compound in alcohol?

Which compound is the least soluble in alcohol: Sucrose, Benzoic acid, or Urea?

What should you observe on the filter paper in Test Tube #1 with a mixture of benzoic acid and sucrose?

Identify which compound is present based on their solubility.

What should you determine about the maximum amount of benzoic acid that dissolves in 10 mL of water?

Calculate the maximum solubility based on the Merck Index.

What should you determine about the maximum amount of sucrose that dissolves in 10 mL of water?

Calculate the maximum solubility based on the Merck Index.

What should you observe on the filter paper in Test Tube #2 with denatured alcohol?

Identify which compound is present based on their solubility.

What should you determine about the maximum amount of benzoic acid that dissolves in 10 mL of alcohol?

Calculate the maximum solubility based on the Merck Index.

What should you determine about the maximum amount of sucrose that dissolves in 10 mL of alcohol?

Calculate the maximum solubility based on the Merck Index.

What should you observe on the filter paper in Test Tube #3 with a mixture of benzoic acid and urea?

Identify which compound is present based on their solubility.

What should you determine about the maximum amount of urea that dissolves in 10 mL of water?

Calculate the maximum solubility based on the Merck Index.

What should you observe on the filter paper in Test Tube #4 with denatured alcohol?

Identify which compound is present based on their solubility.

What should you determine about the maximum amount of urea that dissolves in 10 mL of alcohol?

Calculate the maximum solubility based on the Merck Index.