Lab Report On Chemical Tests

The following tests according to the lab manual were performed: gram stain, fermentation tubes, methyl red, vogues proskauer, sulfur, indole, motility and growing it up on MacConkey agar. The gram stain was performed incorrectly the first time. This is because the decolorizer was not on the bacterium slide for long enough, giving a false outcome.

To begin the separation of the sucrose from the Panacetin, approximately 3 grams of Panacetin was transferred to a 125-mL Erlenmeyer flask. Added to the flask was 50 mL of dichloromethane to dissolve the Panacetin to aid in the separation. A fluted filter paper was used to filter the Panacetin and dichloromethane mixture by gravity using a glass funnel. The remaining filtrate was set aside than transferred to a separatory funnel and the substance on the filter paper was dried and weighed. The filtrate was extracted with 2 increments of 25-mL portions of aqueous 1 M sodium hydroxide. During this step the filtrate in the separatory funnel was shook and vented 3 times.

The Voges-Proskauer test to detect organisms that are able to ferment glucose, but convert the products to acetoin and 2,3-butanediol. This is deduced by the addition of Reagent A and Reagent B, and the observation of the color change thereafter. Reagent A is a solution of -naphthol and alcohol. Reagent A catalyzes the conversion of acetoin to diacetyl. Diacetyl thens react with guanidine-containing compounds from the peptone to form a red color in the presence of -naphthol. Reagent B is a solution of potassium hydroxide and water. It

Experiment 55 consists of devising a separation and purification scheme for a three component mixture. The overall objective is to isolate in pure form two of the three compounds. This was done using extraction, solubility, crystallization and vacuum filtration. The experiment was carried out two times, both of which were successful.

The use of multiple test tubes and Parafilm was used for each experiment. Catechol, potato juice, pH 7 phosphate buffer, and stock potato extract 1:1 will be used to conduct the following experiments: temperature effect on enzyme activity, the effect of pH on enzyme action, the effect of enzyme concentration, and the effect of substrate concentration on enzyme activity. For the temperature effect on enzyme activity, three test tube were filled with three ml of pH 7 phosphate buffer and each test tube was labels 1.5 degrees Celsius, 20 °C, and 60 °C. The first test tube was placed in an ice-water bath, the second test tube was left at room temperature, and the third test tube was placed in approximately 60°C of warm water. After filling the test tubes with three ml of the

The purpose of this lab is to test substances and to determine the physical and chemical properties of substances.

Purpose: To use indicators to test for the presence of organic compounds in certain substances.

To perform this test, a tube of broth rich with glucose is acquired. In this tube is phenol red, a pH indicator. Initially, the tube appeared pink in color, indicating a normal pH level. Next, a sample of unknown #44 is introduced into this medium using the aseptic technique, and this is allowed to sit for several days. If the organism is able to ferment glucose, the pH in the medium would decrease and cause the phenol red to exhibit a yellow color. In addition to the straw color, gas can also be produced and trapped inside the Durham tube placed in the medium. This production of acid and gas is a direct result of the fermentation of glucose, as seen with unknown

Test tube 1 and 2 didn’t show any color change. These two test tubes had lower levels of pH. Therefore, the enzymes could not change the starch to sugar.

The next day an orange goopy textured product resulted. The extracts were then dried and combined with anhydrous sodium sulfate, then evaporated with dry air under the hood in a warm water bath. The liquid was cooled and had an initial weighing of 0.5887g. It was reweighed several minutes later with a final

In part II of the lab six small glass tubes were obtained in a test tube rack. Ten drops of distilled water were then added to test tube 1, five drops to tubes 2-4, and no drops in tubes 5 and 6. Five drops of 0.1M HCl were added to test tube 5 and five drops of 0.1M NaOH to test tube 6. Five drops of enzyme were then added to all tubes except tube 1. Tube 3 was then placed in the ice bucket and tube 4 was placed in the hot bucket at 80-900C for five minutes, the remaining tubes were left in the test tube rack. After the five minutes five drops of 1% starch was added to every tube and left to sit for ten minutes. After ten minutes five drops of DNSA were then added to all the tubes. All the tubes were then taken and placed in the

Introduction: Through the conduction of numerous experiments, the identity of two bacterial isolates was determined. The tested specimen was an unknown sample of a mixed culture of two different species of bacteria. The first step that was taken was obtaining a pure culture of each species of bacteria by isolating one species from the other. Once isolation was complete, the isolated cultures were tested using procedures that had been performed during previous lab sessions. A gram stain was performed on the two isolates. The isolate which had tested gram negative was then tested for the presence of cytochrome C and lactose fermentation. For the gram positive isolate, cell shape was determined and a catalase test was performed.

2cm of a solution was tested and added 2 cm of 10% of potassium hydroxide solution and the test tube was shaked.

Half of each tube’s contents are poured into a new test tube each respectively after the tubes are incubated for 1 hour. One set of tubes is tested for:

During the Benedict's test, the contents of tube B did not change, indicating the absence of sugar in that particular substance. However, the contents of tube A did change orange indicating the presence of sugar in that substance. During the Lugol's test, the content of tube A did not change dark purple indicating the absence of starch in that substance However, the content of tube B changed to dark purple