* 5ml of distilled water was poured down the sides of the beaker, swirled and poured into the funnel. * The filter paper containing the precipitate was allowed to dry and then weighed. 1.7g/1.4g * The weight of the filter paper was subtracted (1.1g/0.7g) to give the actual yield of calcium carbonate (0.6g/0.7g). Observations: * When CaCl2 and Na2CO3 were mixed, a white precipitate was noted immediately. * Residual precipitate was observed on the beaker when filtering.
Indirect Gravimetric Determination of a Hydrated Compound in a Mixture Morgan Dufer I. The purpose of this lab was to find the percent of BaCl2*2H2O in a sample of unknown composition by using gravimetric analysis. II. Pre-lab Questions 1. What mass of MgCO3 is contained in a 2.750g solid sample consisting of only MgCO3 and MgO if heating to decompose all the MgCO3 according to the following equation leaves a solid residue weighing 2.160g?
The buret had used the NaOH thoroughly rinsed three times because at the first titration the NaOH solution was used. About 50Ml the NaOH solution was in a clean beaker and brought it to experiment area. A funnel was used to fill the NaOH into the buret and recorded the initial volume on the buret to the correct number of significant figures. A pipette was used to take 10.00ml HCl into a clean 50mL Erlenmeyer flask. Three drops of phenolphthalein indicator was added into the HCl solution.
What is the identity of the element Z? The two reactions are: Z(OH)2(s) + 2HCl(aq) →ZCl2(aq) + 2H2O(l) HCl(aq) + NaOH(aq) →NaCl(aq) + H2O(l) [Ans. : Mg, calculated molar mass 24.31 g] 6) A sample of “compound X,” known to contain only C and H, was burned and the resulting CO2 and
The synthesis of NaCl further identified the ionic compound by reacting sodium hydroxide and hydrochloric acid and obtaining solid sodium chloride. The synthesized compound formed was used to perform another flame test and the chloride anion test, which further solidified the identification of NaCl as the ionic compound. Introduction The purpose of the experiment was to identify unknown ionic compound
After a small amount of time the solution began to produce gas and the copper was being used up in the reaction. The solution turned an aqua like blue and eventually all of the copper had now been used into this blue solution which was copper nitrate and water, the gas being produced was nitrogen dioxide and the fume hood had removed it during the reaction. Next we slowly added drops of 6 molar sodium hydroxide to the solution until it became basic and turned a red piece of litmus paper blue. While we added NaOH the solution turned green indicating a new reaction had occurred and turned the litmus paper blue. We then began to heat and stir the solution until it changed color again and it turned black with a layer of water on top.
LAB 1 NAME: Amy Rampersad. DATE: Saturday 7th April, 2012. TITLE: PREPARATION OF A SOLUBLE SALT BY A TITRATION METHOD. AIM: To prepare Sodium Chloride crystals by Titration of Sodium Hydroxide with Hydrochloric Acid. APPARATUS: Burette (50 cmᶾ), Pipette (25 cmᶾ), two conical flasks (250 cmᶾ), two beakers (250 cmᶾ), funnel, wash bottle, retort stand, boss and clamp, evaporating dish, pipette filler, hot-plate.
When the solution is acidified during diazotization to form nitrous acid, the sulfanilic acid is precipitated out of solution as a finely divided solid, which is immediately diazotized. The finely divided diazonium salt is allowed to react immediately with dimethlaniline in the solution in which it was precipitated. Mechanism Diazotization: [pic] Diazo Coupling: Methyl orange is often used as an acid-base indicator. In solutions that are more basic than pH 4.4, methyl orange exists almost entirely as the yellow negative ion. In solutions that are more acidic than pH 3.2, it is protonated to form a red dipolar ion.
UNIVERSITI TUNKU ABDUL RAHMAN Faculty Course Year/ Semester Session : : : : Faculty of Science Bac. of Science (Hons) Chemistry Year 3 Semester 1 201105 or May 2011 Unit Code Unit Title Lecturer Assignment : : : : UDEC3254 Spectroscopy and Chromatography II Dr. Lim Chan Kiang 2 Answer all questions 1. A mixture of steroid hormones consisting of cortisone, cortexone and corticosterone was separated using a HPLC silica column eluted with a binary mixture of acetone and hexane (20:80). (i) What is the order of elution time for the above compounds from the HPLC column? (3 marks) (ii) What is the chromatographic mechanism involved?
After 10 seconds, the colorless mixture suddenly turns blue. Concept: Demonstrates a typical clock reaction; shows the effect of the interaction between chemical reactions that have different rates. Materials: • Solution A o 0.6 grams Starch o 30 mLs of Acetic Acid o 4.1 grams of Sodium Acetate o 50 grams of Potassium Iodide o 4.7 grams of Sodium Thiosulfate ▪ Allow mixture to cool and dilute to 1 liter with distilled water o 1 liter flask • Solution B o 500 mLs of 3% Hydrogen Peroxide o 500 mLs of distilled water o 1 liter flask o Safety: Hydrogen Peroxide can be irritating to skin and eyes. Wear safety goggles and gloves. Procedure: Mix the two solutions together.