Introduction: This lab is destined to calculate the cell potential of different electrochemical cell. Electrochemical cells is very useful in everyday life. Thanks to them, we have batteries that powers our mobile phones, laptops and so on.. Electrochemical Cells are devices in which chemical energy released during a chemical reaction is converted into electrical energy . A typical cell might consist of two half cells. Each half-cell consists of cathode, electrode where reduction(gain of electrons) is happened, or anode in which oxidation(loss of electrons) is happened, and electrolyte, a solution containing the corresponding cation(metal) of the half-reaction. The electrode of the half-cells are connected by a wire along which the electrons flow. And two solutions are separated by a salt bridge. As long as electrode is dipped in its electrolyte, potential difference is developed at the metal solution interface. The potential difference between the two electrodes in a galvanic cell is called a cell potential or emf of the cell. Thus magnitude of the potential depends on the nature of metals …show more content…
In experiment 3, iron electrode is defined as cathode, because the more positive (or less negative) the reduction potential, the greater is the tendency for the reduction to occur. So in third experiment, Fe2+ has a greater tendency to be reduced than Zn2+. Moreover, Zn has a greater tendency to be oxidized than Fe. Due to the in the anode is negative electrode in which oxidation reaction is occur, Zn electrode is defined as anode. However, in forth experiment iron act as anode, because the value of E0 of iron is more negative than E0 of copper. The standard reduction potentials are -0.44V for iron and +0.34 V for copper. After the cathod and anode was defined, the cell potential in experiment 2&3&4 was measured. There was some inconsistencies with theoretical value of the cell
An error that could have been present during the lab includes not letting the zinc react completely with the chloride ions by removing the penny too early from the solution. For instance, the percent error of this lab was 45.6%, which was determined by the subtraction of the theoretical percent of Cu 2.5% and the experimental percent of Cu 3.64% and dividing by the theoretical percent of Cu 2.5%. This experiment showed how reactants react with one another in a solution to drive a chemical reaction and the products that result from the
Consequently, it induces second element to be oxidized. 2. In the experiment #3, zinc electrode acts as anode, where the oxidation processes occur, while iron half-cell acts as cathode, where the reduction processes appear. In the experiment #4, iron is visa verse reducing agent that evicts electrons to copper half-cell through the circuit.
Cadet Eric Wiggins Date: 18 September 2014 Course Name: Chem 100 Instructor: Captain Zuniga Section: M3A Identification of a Copper Mineral Intro Minerals are elements or compounds that are created in the Earth by geological processes. The method of isolating metals in a compound mineral is normally conducted through two processes.
The purpose of this lab was to be able to use physical characteristics to determine the identity of an unknown compound. The data from this experiment classified aluminum as metallic; ascorbic acid, paraffin, palmitic acid, sucrose, graphite, and water as molecular; sodium chloride as ionic. In order to determine this, 3 tests were conducted. The first test was to test the conductivity of each substance at room temperature. In this test, only graphite and aluminum conducted.
During this experiment, mitochondria were isolated from 20.2 grams of cauliflower using extraction buffer, filtration through Miracloth, and centrifusion. Twelve samples containing various volumes of mitochondrial suspension, assay buffer, DCIP, sodium azide, and citric acid cycle intermediates were prepared to be read by a spectrophotometer. The inclusion of the dye DCIP allowed for the absorbance of the reactions between the mitochondrial suspension and the TCA cycle intermediates succinate, malonate, and oxalate to be measured, as DCIP turns from blue to colorless as the activity of succinate dehydrogenase increases. Experimental Findings Increasing the number of mitochondria in the reaction did increase the reduction of DCIP relative to the amount of mitochondrial suspension present.
The lab started off by measuring critical materials for the lab: the mass of an an empty 100 mL beaker, mass of beaker and copper chloride together(52.30 g), and the mass of three iron nails(2.73 g). The goal of this experiment is to determine the number of moles of copper and iron that would be produced in the reaction of iron and copper(II) chloride, the ratio of moles of iron to moles of copper, and the percent yield of copper produced. 2.00 grams of copper(II) chloride was added in the beaker to mix with 15 mL of distilled water. Then, three dry nails are placed in the copper(II) chloride solution for approximately 25 minutes. The three nails have to be scraped clean by sandpaper to make the surface of the nail shiny; if the nails are not clean, then some unknown substances might accidentally mix into the reaction and cause variations of the result.
The purpose of this experiment was to learn about the electrophilic aromatic substitution reactions that take place on benzene, and how the presence of substituents in the ring affect the orientation of the incoming electrophile. Using acetanilide, as the starting material, glacial acetic acid, sulfuric acid, and nitric acid were mixed and stirred to produce p-nitroacetanilide. In a 125 mL Erlenmeyer flask, 3.305 g of acetanilide were allowed to mix with 5.0 mL of glacial acetic acid. This mixture was warmed in a hot plate with constantly stirring at a lukewarm temperature so as to avoid excess heating. If this happens, the mixture boils and it would be necessary to start the experiment all over again.
The negatively charged protein molecules (A-) inside the neuron cannot cross the membrane. In integration to these selective ion channels, there is a pump that utilizes energy to move three sodium ions out of the neuron for every two potassium ions it inserts. Conclusively, when all these forces balance out, and the difference in the voltage between the inside and outside of the neuron is quantified, have the resting membrane potential. The resting membrane potential of a neuron is about -70 mV (mV=millivolt) - this designates that the inside of the neuron is 70 mV
2-a. The current drawn by each shunt resistor is linearly proportional to the cell voltage. As the cell voltage increases, more current is drawn by the shunt resistor. This will decrease the voltage differences between the different cells within the battery system since higher voltage cells is further discharged by the shunt resistors. It is worth mentioning that this method can be only used for Lead-acid and Nickel based batteries because they can be brought into overcharge conditions without cell damage [4r]. Its features are simplicity, low cost but the excess energy is converted into heat losses in the shunt resistors.
Copper Cycle Lab Report Ameerah Alajmi Abstract: A specific amount of Copper will undergo several chemical reactions and then recovered as a solid copper. A and percent recovery will be calculated and sources of loss or gain will be determined. The percent recovery for this experiment was 20.46%.
The effects of alcohol on Biological Membranes. Introduction In this experiment it will be analysed the damage alcohols can have on biological membranes. Membranes are made up of lipids and proteins. Membranes usually help maintain the balance in a cell as it holds all the cellular materials.
Chemistry IA Background information: Introduction: Electrolysis it’s a chemical process that when you pass an electric current into a solution or a liquid that contains ions to separate substances back to their original form. The main components that are required for electrolysis to take a place are: Electrolyte: it’s a substance that when dissolved in water it ionize and then it will contain free moving ions and without these moving ions the process of electrolysis won’t take place. Direct current (DC): This current provides the energy needed to discharge the ions in the electrolyte Electrodes: it’s an object that conducts electricity and it’s used in electrolysis as a bridge between the solution and power supply. A great example
Properties of Ionic and Covalent Substances Lab Report Introduction The purpose of this lab was to determine which of the following substances: wax, sugar, and salt, are an ionic compound and which are a covalent compound. In order to accurately digest the experiments results, definitions of each relating factor were researched, leading to the following information: ionic compounds are positive and negatively charged ions that experience attraction to each other and pull together in a cluster of ionic bonds; they are the strongest compound, are separated in high temperatures, and can be separated by polar water molecules. A covalent compound is formed when two or more nonmetal atoms share valence electrons; covalent compounds are also categorized into two sections: polar covalent and nonpolar covalent. Furthermore, polar covalent compounds dissolve in water, while nonpolar covalent compounds do not.
Biochemical tests are the tests used for the identification of bacterial species based on the differences in the biochemical activities of different bacteria. Bacterial physiology differs from one species to the other. These differences in carbohydrate metabolism, protein metabolism, fat metabolism, production of certain enzymes and ability to utilize a particular compound help them to be identified by the biochemical tests. Gram’s stain was originally devised by histologist Hans Christian Gram in 1884. Gram-positive bacteria stain purple, while Gram-negative bacteria stain pink when subjected to Gram staining.
This means there is no movement of ions in or out of the cell membrane and a resting potential is attained. At this point, there are more sodium ions outside the cell membrane and more potassium ions inside the