Priya Talwar
Chemistry 1411-008, (Group 06 Partners: Esther, Bethany, Sophia)
19 October, 2017
CSI: How to identify an unknown white powder
Jiayue Sun
Introduction
The Identity of a chemical compound is extremely critical to observe. The identity can lead to discovering its properties and can aid in its classification. Thus scientist all around the world put high emphasis on the procedure to identify a compound through the flame test and chemical testing. Flame test works to identify the cation within the compound, while chemical testing using certain compounds and acid identifies the anion.
Flame test uses the differences of energy levels of an element. When the flame, from the micro burner used, excites the electrons in their ground state, the electrons absorb the energy and move to a higher energy level. Yet since the ground state is preferred, the electrons tend to move down the energy level and emit the extra energy absorbed. This type of energy is emitted through photon and wavelength, a characteristic of light. Thus, each element emits a certain type light which can be used to identify it by consulting a chart with all the documented flame test results. In Particular for this experiment, the test for ammonia and Magnesium is conducted with the addition of sodium hydroxide and the observing for the presence of the odor of ammonia for ammonia or precipitate for magnesium.
The chemical testing uses compounds including acids and alkaline to combine with the element.
6-3: This process is used by cells to manufacture _biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products__
3. Removed the test tube from the flame and places a piece of moistened litmus paper in the mouth of the test tube. Identified any odor that is readily apparent by wafted the fumes toward your nose. Caution: Do not sniff
The first experiment is about the combustion of magnesium after which the ash is formed.
The primary goal of this laboratory is to correctly identify an unknown substance. To achieve this task, one may use various tests that reveal both chemical and physical properties of a substance. By comparing the results of a known substance and the unknown substance, one may eliminate alternative possibilities and more accurately predict the undisclosed compound. Furthermore, by performing these tests, data can be collected and verified regarding chemical and physical properties of the unknown. Understanding the chemical properties of a known substance aids one’s understanding of the unknown based on comparative analysis of the results of the tests.
The purpose of this lab is to test substances and to determine the physical and chemical properties of substances.
A chemical reaction is when substances (reactants) change into other substances (products). The five general types of chemical reactions are synthesis (also known as direct combination), decomposition, single replacement (also known as single displacement), double replacement (also known as double displacement), and combustion. In this lab, the five general types of chemical reactions were conducted and observations were taken before, during, and after the reaction. Then the reactants and observations were used to determine the products to form a balanced chemical equation. The purpose of this lab was to learn and answer the question: How can observations be used to determine the identity of substances produced in a chemical reaction?
In a chemistry stockroom, a vial of an Unknown White Compound was found. In order to properly dispose of the substance, the substance has to be identified .The possible compounds has been limited to one of 15 different compounds. Also, approximately 5 grams of the Unknown White Compound (UWC) were available for testing. In order to determine the properties of the compound, a series of tests was conducted. These tests included a ph test, a conductivity test, a flame test, a sulfate test, a halide test, an ammonium test, a solubility test, and a carbonate test. Using the results of these experiments, it was hypothesized that the UWC is potassium chloride. To further confirm the hypothesis, a synthesis of potassium chloride was conducted.
Examine a piece of nichrome wire. On the data sheet, record the color and the luster of the metal. Use a forceps to hold the wire in the flame of your burner for about two minutes (recall where the hottest part of the flame is located). Describe the appearance of the wire while held in the hottest part of the flame. Allow the wire to cool and reexamine it. From your observations, determine if there was a physical or a chemical change. Give specific reasons for your conclusions. Save the nichrome wire for step #2.
Substances A and B have an appearance of a white solid like. Substances A and B were put into a test tube and on the Bunsen burner. As a result, B melted faster than A. A was slow to melt. The reason why B melted faster than A is because it has a lower boiling point than substance A which made it melt faster. It also shows that A needs more energy than B to be broken down.
3.6.1. BAP (Benzyl amino purine) stock solution (2mg/ml): 20mg of BAP being weighed and dissolved completely in 1N NaOH to a final total volume of 10 ml with autoclaved double distilled water to obtain a stock concentration of 2mg/ml was prepared and stored in clean autoclaved vials at -4°C.
5. Zoom Out by clicking on the green arrow next to the Save button. Click on the Stockroom and then on the Clipboard and select Balloon Experiment N2. Again, set the temperature, pressure, and moles to 298 K, 1.00 atm, and 0.300 moles, respectively. You may have to click on the Units button to change some of the variables to the correct units. Repeat the experiment with this gas labeling the data link ‘Real Gas N2.’
Purpose: The purpose of this experiment is to observe a variety of chemical reactions and to identify patterns in the conversion of reactants into products.
The luminous yellow flame is smoky because no air is entering the burner and hydrocarbon is converted into carbon dioxide
A chemical change is a change that alters the identity of a substance. A chemical change can be identified by five things: change in mass, formation of a precipitate, release of heat and/or light, color change, or giving off gas.
Once a light beam shines through the flame, the atoms absorb some of the light. It is then detected, recorded and compared to a series of standard solutions. In the absorption spectrum, the absorbed light show up as black gaps. These distinctive gaps indicate the difference in energy levels for a particular element. If this can be compared to the concentration of its standard solution, then it can form a calibration curve.