The second experiment, procedure 1, combined [Co(NH3)5 (H2O)]Cl2 (0.0060M, 1.52g) and (25mL) of distilled water to an 125mL Erlenmeyer flask. The flask was gently heated (dial 5-6) and stirred until all the compound was dissolved. The heated solution was then vacuum filtered through a fritted funnel and the filtrate was cooled in an ice bath until the
Add 0.5 ml concentrated HCl and 1.0 ml 15% KI solution. Mixed exactly 1 minute and leave for 5 minutes in a dark place. Add 0.5 ml starch solution, 20 ml distilled water. Mix and titrate with sodium thiosufate solution. Calculate the exact normality of Na2S2O3 knowing that in this chemical reaction 1 gram-equivalent of K2Cr2O7 react with 1 gram-equivalent of Na2S2O3 (1 mole K2Cr2O7 react with 6 moles Na2S2O3).
Titration Aim Part A: To prepare a primary standard and use it to determine the concentration of a sodium hydroxide solution. Part B: To monitor the neutralisation of dilute vinegar by a standardised sodium hydroxide solution to determine the concentration of acetic acid in dilute vinegar. Equipment • 250mL volumetric flask • Oxalic acid dehydrate crystals • Beaker (150mL) • Small funnel • Phenolphthalein • Burette • Wash bottle with distilled water • Electronic balance • Pipette (25mL) • 2 x Beaker 50mL • Burette clamp and stand • Pipette filler • Spatula • Glass rod • pH meter and data logger • Standardised NaOH solution • Diluted vinegar (150mL diluted into 1L with distilled water) • Sample of 0.1mol/L sodium hydroxide solution • Magnetic stirrer with stirrer • 100mL measuring cylinder Method Part A: Preparation of Standard Solution 1. The molar weight (M) of oxalic acid dehydrate was calculated. 2.
Most differential stains have a challenge step that follows staining with a primary dye. In the Gram stain the challenge step is a rinse with either ethanol or acetone (either may be used). This step dehydrates and tightens the cell wall of Gram positives (mainly peptidoglycan) such that the rinse does not enter the cell. Gram negatives have mainly a lipid cell wall (even though they do contain peptidoglycan) that allows the challenge rinse to penetrate the cell and rinse out the crystal violet-iodine complex rendering the Gram negative cell colourless. Thus, the Gram negative cells must be stained to be seen, and this is done with the counter stain.
Quantitative data deals primarily with numerical characteristics, such as the weight or amount of a particular substance. Qualitative data, however, refers to observable characteristics such as taste, touch, smell, etc. It should be noted, however, that qualitative data can be converted into quantitative data, provided that there is a numerical rubric or basis for gradation. In chemistry, qualitative data allows chemists to generally identify the presence of certain types of ions, elements, compounds, etc. that are present in a sample, by generally observing the physical and chemical properties of the sample when they react with compounds with known reagents.
Take the fine soil from the bottom pan of the sieve set, place it into a beaker and add 125mL of the dispersing agent. Stir the mixture until the soil is thoroughly wet. Let the soil soak for at least ten minutes. 2. While the soil is soaking, add dispersing agent into the control cylinder (Sodium Hexametaphosphate 125ml) and fill it with water to the mark.
Gravimetric Determination of Sulfate Purpose The purpose of this lab is to determine the percentage of sulfate in the hydrate by precipitating the sulfate as barium sulfate. Materials Filler paper Sodium sulfate Graduated cylinder Bunsen burner Watch glass Beakers (250 mL, 400 mL) Rubber bulb Graduated pipette Beaker tongs Funnel Filter Paper Sodium Sulfate Drying oven Wash bottle Stirring rod Silver nitrate Hydrochloric acid Distilled water Small test tube Procedures First, .4861 grams of sodium sulfate was placed into a clean 400mL beaker. Exactly 200mL of water and 1mL of HCl was added to the same beaker. A watch glass was placed on the beaker and the solution was heated using the Bunsen burner to a gentle boil. The watch glass was removed with the beaker tongs.
TITLE OF THE EXPERIMENT: Separation and Purification Chemical separation of a mixture of acidic (benzoic acid), basic (p-bromoaniline) and neutral (naphthalene) compounds. PART A Introduction: Most of the reactions in synthesis of organic compounds give products that are usually impure [1+2]. Two of the most common reasons that impurity appears in organic synthesis are i) contamination with the reactants due to incomplete reactions during the preparation or ii) the presence of other compounds in alternative competing reactions. So a process with various techniques called purification is carried out to the organic compounds to restrict the influence of impurities and make them able to be used further in the lab or in industry . Purification process can be applied either in starting materials (reactants) or the final material (product) but to avoid though any initial imperfections, purification of the final material is more preferable .
Testing Saccharides Saccharides, which are also known as carbohydrates, are the most essential biomolecule for the human body. Carbohydrates are what run the body to function. Saccharides help your brain and nervous system to function properly. What we were testing in both experiments was to see if there was a presence of saccharides. More specifically in these experiments, we tested if there were reducing sugars with the Benedicts reagent in the first experiment and if there were starches present with Lugol’s solution in the second experiment.