Determination of the molar mass of a chosen compound/element Fran Jurinec 1.M Introduction Molar mass is a physical property of a chemical element or substance which shows the mass per amount of substance. My task is to determine the molar mass of a product substance from one of the following equations: a. Zn(s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g) b. CaCO3 (s) + 2HCl(aq) → CaCl2 (aq) + CO2 (g) + H2O(l) c. Na2SO3 (aq) + 2 HCl (aq) → 2NaCl (aq) + S (s) + SO2 (g)
Purpose/Introduction The process of recrystallization is an important method of purifying a solid organic substance using a hot solution as a solvent. This method will allow the separation of impurities. We will analyze Benzoic Acid as it is dissolved and recrystallized in water and in a solvent of Methanol and water. Reaction/Summary
CH 204- Intro to Chem Practice Experiment 3-Enthalpy of Chemical Reaction Dana Lucas Robin Brown TA: Chris February 19, 2018 Introduction The purpose of this experiment was to calculate the change in enthalpy of 2 reactions using Hess’ Law by using a coffee calorimeter to measure the temperature changes in the sub reactions for MgO and a neutralization reaction. Germain Hess published this law in 1840, which described the first law of thermodynamics.
Abstract: The purpose of this experiment was to identify given Unknown White Compound by conducting various test and learning how to use lab techniques. Tests that are used during this experiment were a flame test, ion test, pH test, and conductivity test. The results drawn from these tests confirmed the identity of the Unknown White Compound to be sodium acetate (NaC2H3O2) because there were no presence of ions and sodium has a strong persistent orange color. The compound then will be synthesized with the compounds Na2CO3 and HC2H3O2 to find percent yield.
Experiment 2: Preparation and Spectrophotometric Analysis of Copper(I) Iodide Abstract: This experiment aims to determine the concentration of “Purified CuI” sample. Crude CuI is obtained by reacting CuSO4.5H2O with KI and Na2S2O3 in de-ionized water. A series of decanting and centrifugation is carried out to extract the crude CuI. Crude CuI was later purified by dissolving it in hot KI solution. The solution was later transferred into de-ionized water and placed in an ice bath to allow for re-precipitation of “purified CuI” to settle.
BS1003 – Organic Chemistry Practical 1 Laboratory Report Name: Tristan Chan Yew Kit, U1640436J (T8) Effects of Dichloromethane(DCM) in Extraction of Caffeine from Tea Leaves Purpose To investigate the ability for Dichloromethane(DCM), a moderately polar organic solvent, to extract aqueous caffeine molecules, originating from Tea Leaves suspended in water. Introduction Caffeine, defined chemically as 1,3,7-trimethylxanthine (C8H10N4O2), is an alkaloid that can be found in tea leaves, coffee and many other plant species. The amount of caffeine in dry tea leaves varies from 2-5% between different species of plants. Caffeine has uses in the medicinal industry, with the ability to act as a vasodilator, diuretic, and aid in stimulation of the central
Tyler White CHEM151LL 32658 04/01/2018 Different Types Chemical Reaction Types and Equations Purpose: The purpose of this lab experiment is to examine different types of chemical reactions such as Decomposition reaction, Synthesis reactions, Combustion reactions, and different Chemical equations. The experiments were conducted online using Late Nite Labs. Materials: Because the experiments were conducted online there wasn’t any physical use of materials, only digital ones, for these labs to be performed. Only the registration for the website was needed to perform these online labs, as well as a desktop computer.
Determination of antioxidant activity Scavenging DPPH radicals DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical is used free radical method is an in antioxidant assay forwas used to evaluate measured the free radical scavenging activity of the lichen extract . Two millilitreers of 0 .05 mg/mL methanol solution of DPPH radical in the concentration of (0 .05 mg/mL) and 1 mL of the lichen extract (1 mg/mL) were placed in cuvettes. The mixture is storewas stored stand at room temperature for 30 min. Then, the absorbance was measured at 517 nm in a spectrophotometer (Jenway, UK). Ascorbic acid was used as a positive control.
A mobile phase system consisting of acetonitrile and 25mM phosphate buffer of pH 3(sodium dihydrogen phosphate monohydrate adjusted with orthophosphoric acid) in a ratio 60:40 (v/v) were used. The mobile phase was degassed and filtered by passing through 0.45 µm pore size membrane filter (Millipore, Milford, MA, USA) prior to use. The flow rate was 1.0 mL min-1 all over the run. The injection volume was 20 µL. The eluent was monitored by the diode array detector (DAD) which was set at 250 nm for the quantitation of both VAL and SAC.
Experiment 2: Distillation and Purification of Liquids Angela Kaiser 100125701 ELL 308 September 19th, 2015 Introduction and Experimental: The purpose of this experiment was to determine the ratio of dichloromethane (DCM) to cyclohexane in a DCM/cyclohexane solution by carrying out a fractional distillation. The temperature and volume of distillate were measured periodically to determine the volume both components in the solution. The experiment was performed as written in “Experiment 2: Distillation and Purification of Liquids” from the Chemistry 2050 Lab Manual for Organic Chemistry Part 1, Fall 2015. Results and Observations: