Using a Buchner funnel, a hose, and a suction flask we created a vacuum filtrator which we used to help remove the remaining liquid on the copper so that we may make a more precise measurement of the mass of the remaining copper. Our final mass of copper was .7951 grams. Results and Discussion: Initial Mass of Cu: .25 grams When we mixed the 5 ml of 6 molar HNO3 the copper had disappeared, indicating it had been used in the reaction. The copper had undergone a single replacement reaction and a decomposition reaction. Initial equation: Cu(s) + HNO3(aq) -> Cu(NO3)2(aq) + NO2(g) +H2O(l) Balanced: Cu(s) + 4HNO3(aq) -> Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l) The copper had replaced the Hydrogen in the HNO3 and the NO3 had also broken down into NO2 and O2- allowing the H+ to bond with it and create
CHEMISTRY September 25, 2010 Experiment #5: Percentage of water in a Hydrate Summary of Principles In this lab, students will calculate the amount of water in an unknown hydrate. A hydrate is a compound with a specific number of water molecules associated with the ions of that compound. A hydrate may form when an anhydrous compound is exposed to atmospheric water or when the ionic compound is crystallized from an aqueous solution. An anhydrous compound is a substance without water. There are two parts to this lab.
The two unknown solids are weighed to a mass of 0.15g each. The unknown solids are dropped carefully into the corresponding Erlenmeyer flask wit 50mL of distilled water. The solid in the water must be dissolved and afterwards add 10 drops of Bromecresol green to indicate the change of color when the solution has been titrated. The flask should start with a blue tint. HCl is carefully dropped into the Erlenmeyer flasks with the primed pipette until the solution turn to a green tint.
Abstract The focus of this experiment was to analyze the kinetics of a nucleophilic substitution. A mixture of 0.3622-M 1-bromopropane and 0.3622-M potassium hydroxide in an 90:10 ethanol/water solvent provided the reactants for a SN2 reaction to occur in a temperature controlled bath at 50.0˚C. The disappearing reactant was found by titrating timed aliquots during the reaction and then measuring the concentration of hydroxide. The k-value was found to be 0.0202 M-1Min-1. Using the linear form of the Arrhenius equation the activation energy was calculated to be 19.9 kcal/mol.
For a single extraction, use a 50mL graduated cylinder and measure out 50mL of the benzoic acid solution into a 125mL separatory funnel. Add 10mL of methylene chloride (dichloromethane or CH2Cl2 for abbreviation which is the organic layer), the extracting solvent, to the funnel. Shake the funnel for thirty seconds pointing it away from the student and self. Release gas buildup by opening the stopcock of the separatory funnel. This is called the shaking and venting procedure.
Acid Base Titration Purpose: The purpose is to calculate the molarity of a NaOH solution by titrating the base with 5mL of standard HCl solution in each trial. By adding the base with unknown molarity to the acid with 0.10M the molarity of NaOH can be calculated. The base, NaOH, helps bring the pH of the acid, HCl, closer to seven, which neutralizes it. When using the buret the amount of NaOH used is able to be determined. Then by writing a balanced chemical equation and using the titration formula, Nb+Ma+Va=Na+MbVb , the molarity is able to be determined.
The third test will utilize thin layer chromatography to evaluate the purity of the aspirin as well as testing for the presence of leftover salicylic acid or other by products of the reactions. Experimental: Week 1: For the synthesis of the aspirin, 250 mL of water was boiled. 1.5 g. of salicylic acid were poured on a test tube. Then, 3.5 mL of acetic anhydride and four drops of 85% phosphoric acid were added. A cotton ball was placed to prevent vapor escape.
A 125mL Erlenmeyer Flask was used to combine (15mL) of concentrated aqueous ammonia and ammonium chloride (0.0467mol, 2.49g). The mixture was stirred till fully dissolved. Colbalt (II) chloride hexahydrate was ground (6.2g) and added in small amounts to the stirring solution (0.0210mol, 5.2g). As the mixture continued to stir (4mL) of 30% hydrogen peroxide was added drop wise to yield a dark warm slurry. After the effervescence, (15mL) of concentrated HCl was added drop wise to the solution.
TITRATION OF SULPHURIC ACID WITH SODIUM HYDROXIDE Modified: November 3, 2002 INTRODUCTION A TITRATION is a process in which a measured amount of a solution is reacted with a known volume of another solution (one of the solutions has an unknown concentration) until a desired end point is reached. (The “end point” of a titration is the point in the titration at which an indicator dye just changes colour to signal the stopping point of the titration.) In this experiment, you will use a PIPETTE to measure some sulphuric acid into a beaker. The sulphuric acid has an unknown concentration. Then you will fill a BURETTE with sodium hydroxide (a base) that has a known concentration.