Environmental chemistry

5-CinthiaV-Selenium The name of my element is Selenium. The element symbol is “Se”. Selenium was discovered in Sweden by Jons Jacob Berzelius in 1817. Selenium is an origin for a greek word meaning moon. Selenium has four energy levels. In the first energy level, it has two electrons. The second energy level has eight electrons. The third energy level has 18 electrons. The fourth energy level has six valence electrons. Selenium has forty-five neutrons. Selenium has the…

Cellular Death: Tonicity on Potato Cells Introduction The purpose of this experiment was to test the effects of tonicity on potato cells. During this experiment slices of a potato were placed into beakers containing salt solutions with different concentrations. How will the percentage of salt concentration in solution affect a plant cells water content? This experiment will determine which salt solution concentrate will cause the potato cells to absorb water or lose water. Tonicity in…

Chemistry Honors Mrs. Moreno Period 5 INTERPRETING THE PERIODIC TABLE Partner’s name: Faranak Hajikhan, Pablo Moncada, Albina Contreras and Karla Santos Title: Interpreting the Periodic Table Date: 12-18-14 Subject: Honors Chemistry / Period 5 Introduction: The periodic table is a table of the chemical elements in which the elements are arranged by order of a atomic number. The periodic table also has a special name for its vertical columns. Each…

Trayc Poppenhager May 5, 2015 TA: GK Chem 341 Thermodynamics and Kinetic Control Goal: The overall goal of this experiment was to learn and observe about kinetic and thermodynamic control of different reactions by noticing which product forms faster or slower and possibly which reaction is more stable than the rest of the reactions. Significance: Organic chemists find using kinetic and thermodynamic control useful because they use the concept of the reactions to figure out…

Introduction Four reactions were done using coffee cup calorimetry for each. Two Styrofoam cups were stacked together for each reaction performed, with a piece of cardboard used as lid with a hole for the thermometer. The beginning and final temperatures were taken for all reactions and solvents used. The end result and point of the experiment is to find what ΔH. Also this is a constant pressure calorimetry experiment. The goal of each of the reactions is to get ΔHrxn which is represented in…

After letting the potatoes sit for a few days. The potato in the freshwater solution was soft and sticky, it could be easily squished it also had a bad scent because the potato had gone bad. However, the potato in the saltwater solution was firm and had become more narrow than before, it did not have a scent like the freshwater potato did. The solution that caused the potato to change the most in circumference and mass, was the saltwater solution. In the data table the potato in the fresh water…

To demonstrate their effectiveness in creating new carbon to carbon bonds, the Grignard arylation of 2-butanone was carried out. The Grignard reaction of phenyl bromide and magnesium, followed by the addition of 2- butanone yielded a crude product of 2-phenyl-2-butanol. The 1H NMR spectra was taken before distillation, showing the crude product, as well as after distillation, showing one of greater purity. In addition, an IR spectrum was taken after distillation. Both the 1H NMR and IR spectra…

Limiting reactants occur in a reaction when one of the reactants runs out and there is excess of another reactant. It is important to understand limiting reactants because it allows us to adjust the amount of chemicals we need to create a product without having excess chemicals. On October 5, 2017, we completed a lab in which we determined which chemical was the limiting reactant in a reaction by adding each chemical to the excess chemical and observing which formed a precipitate. II. Data,…

regular tap water, this is because tap water could itself contains many unwanted impurities such salts, other solids and bacteria. If these were to contaminate the solutions to be used it would create a margin of error in your results. In analytic chemistry there are four main pieces of glassware used which must be cleaned carefully and appropriate Burette The burette is to first be cleaned with deionised water, this is to remove and contaminants…

The purpose of this lab was to use NMR, Recrystallization, TLC, and Melting point to separate and identify the components of a given unknown mixture. The first step of the experiment was to use the two NMR spectra given to identify the major and minor components of the unknown mixture. When an external magnetic field is applied, there is a quantized interaction between the magnetic field itself and the magnetic moment of the proton. Thus, the magnetic moment of the proton either applies with or…