Electrochemistry is a branch of chemistry which primarily focuses on the flow of electrons and the chemical reactions which occur due to the flow of those electrons. These chemical reactions are known as oxidation-reduction reactions, or simply redox reactions. Electrical energy provides the energy needed for the redox reactions to occur. Where oxidation occurs, reduction is certain to follow. Oxidation entails an increase in oxidation number, signifying a loss of electrons. Reduction entails a decrease in oxidation number, signifying a gain of electrons. A metal could be oxidized or reduced, depending on the products used in the reaction. This can be shown by dividing the net chemical equation into two half-equations: one demonstrating the …show more content…
The substituents were as follows: (1) a copper strip in Cu2+ cation solution, (2) a zinc strip in Zn2+ cation solution, and (3) a lead strip in Pb2+ cation solution. Each metal substituent in their corresponding metal cation solution were placed inside of a test tube, with a small fold of each strip made on the lip of the tube. This created three half cells – one copper, one zinc, and one lead. The circuit was completed by placing each end of a salt bridge (composed of potassium nitrate solidified into gelatinous agar) into two separate half cells containing different metals. The voltage of the voltaic cell was measured with the voltmeter, connecting the alligator leads to each fold of the metal strip on the outer lip of the test tube. Three measurements were taken, time using a new, clean salt bridge. The voltages generated by the Pb/Zn, Pb/Cu, and Cu/Zn cells were recorded and tabulated into figure 1.
As shown in Figure 1, each metal half cell combination included the oxidation of one metal and the reduction of the other. Given that the reduction cell potential of Cu2+ is equal to 0.34 V (Equation 4), the data from Figure 1could be plugged into Equation 5 (manipulated into Equations 6 and 7) to calculate the reduction half cell potentials of zinc (Equation 8) and lead (Equation 9) when combined with copper. The determined values for zinc and lead were, respectively: -0.740 V and -0.145
Purpose: The purpose of the lab was to perform a series of chemical reactions in order to transform copper within different reactions in order to start and end with solid brown copper.
Introduction: The purpose of this lab was to cycle solid copper through a series of chemical forms and return it to its original form. A specific quantity of copper undergoes many types of reactions and goes through its whole cycle, then returns to its solid copper to be weighted. We observed 5 chemical reactions involving copper which are: Redox reaction (which includes all chemical reactions in which atoms have their oxidation state changed), double displacement reaction, precipitation reaction, decomposition reaction, and single displacement reaction. 4HNO3(aq) + Cu(s) --> Cu (NO3)2(aq) + 2H2O (l) + 2NO2(g) Oxidation reduction reaction Cu (NO3)2(aq) + 2 NaOH (aq) --> Cu (OH)2(s) + 2 NaNO3(aq) Precipitation Reaction Cu (OH)2(s) + heat --> CuO (s) + H2O (l) Decomposition reaction CuO (s) + H2SO Data Results: (mass of copper recovered / initial mass of copper) x 100 Mass of copper recovered: 0.21 Initial mass of copper: 0.52 (0.21/0.52)x100 =40.38%.
Kranzler, J. H., Flores, C. G., & Coady, M. (2010). Examination of the Cross-Battery Approach
In the first part of this project, two cation elimination tests and one cation confirmation test were performed. 10 drops of 4 cation solutions: potassium, zinc(II), copper(II)
Investigating Which Metal Combination Gives Out the Most Voltage in a Solution Background Metals are an order of chemical elements in the periodic table. They are arranged in atomic number. All of them are solid (apart from mercury), good thermal and electrical conductors and are shiny when polished. Metals and non - metals are separated in the table by a diagonal line.
Electrolysis is the only permanent hair removal methods that can help you achieve and maintain a smooth, hair-free beautiful aspects. This is a convenient, low-Charge strategy to refresh your image, increase your confidence and enhance Your enjoyment of life everyday.
Electrolyte can be defined as the aqueous or molten substances which when dissolved in a solvent dissociates into ions and can transmit negatively charged ions.
The “blue-bottle” experiment demonstrates a redox reaction. This is one of the most common reactions in chemistry. Redox reactions are the movement of electrons from one substance to another. The word “redox” comes from the concepts of reduction and oxidation. Reduction is the intake of an electron by an atom. Oxidation is the opposite. It is the loss of an electron by an atom. These two reactions go hand in hand because in a chemical reaction, one reaction cannot happen without the other.
So a transfer of electrons takes place between the zinc and the acid. The zinc is oxidized and the acid is reduced to hydrogen gas which you can see bubbling out around the electrodes. The reaction at the penny electrode depletes the electrons from the copper and attaches them to the hydrogen ions in the phosphoric acid.
Another widely used primary cell is the zinc-mercuric-oxide cell, more commonly called a mercury battery. It can be made in the shape of a small flat disk and is used in this form in hearing aids, and electric wristwatches. The negative electrode consists of zinc, the positive electrode is of mercuric oxide, and the electrolyte is a solution of potassium hydroxide. The mercury battery produces about 1.34 volts.
... the reaction to shift to the right would be to remove products. A third way is to change the temperature. Since this is an endothermic reaction, +∆H, we can imagine that “heat” is a reactant. Thus, if we add heat, it will shift to the right. To be classified as a redox reaction, we need at least two elements to change oxidation states. The easiest way to look at a reaction and determine this is if you have an element by itself on one side of the reaction and it is in a compound on the other side. Most of the time, the oxidation number of each element in a compound is their common charge. The sum of oxidation numbers must equal the compounds overall charge. Elements in the natural state (by themselves) have an oxidation number of 0. The reducing agent is the species responsible for reducing the other chemical. Therefore, the reducing agent is oxidized itself.
The Electrolysis of Copper Sulphate Aim Analyse and evaluate the quantity of Copper (Cu) metal deposited during the electrolysis of Copper Sulphate solution (CuSo4) using Copper electrodes, when certain variables were changed. Results Voltage across Concentration of solution electrode 0.5M 1.0M 2.0M 2 5.0 10.6 19.5 4 10.5 19.8 40.3 6 14.3 26.0 60.2 8 15.2 40.4 80.3 10 15.0 40.2 99.6 12 15.1 40.0 117.0 Analysing/Conclusion The input variables in this experiment are; concentration of the solution and the voltage across the electrodes. The outcome is the amount of copper gained (measured in grams) at the electrodes. By analyzing the graph, we can see the rapid increase of weight gained for the 2.0 molar concentration as the gradient is steeper.
The electrodialysis setup consists of: an ED cell, a power DC, a brine tank, a feed tank, an electrode rinse tank, three centrifugal pumps (P = 84W, total head = 4.2 m) equipped each with a flowmeter and three valves to control feed flow rate. Fig. 2 shows a simplified diagram of the electrodialysis setup working in continuous mode.
It involves collisions between the free electrons, the fixed. particles of the metal, other free electrons and impurities. These collisions convert some of the energy that the free electrons are. carrying heat, which means that electrical energy is lost. Apparatus: I will be using an Ammeter.
Oxidation is an electrochemical reaction in which metals lose electrons to oxidizing reactants [5] [7][8] [6] [9]. Oxidation produces a crystallographic ally distinct solid compound as there action product. Thermodynamically, oxidation reactions with air or oxygen can be represented by: