Determining the composition of pennies with redox reactions Introduction: The understanding of oxidation and reduction must be clear to carry out this lab. With the understanding of these concepts we can calculate or hypothesize for the properties of each element or compound. Oxidation involves the gain of electrons of hydrogen or the loss of oxygen or decrease in oxidation state. If zinc completely reacts with HCL‚ then the theoretical yield of copper should be equivalent to the actual yield
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Purpose Determine which kinds of reactions involve electron transfer as the driving force. Background Redox (reduction-oxidation) reactions include all chemical reactions in which atoms have their oxidation state changed. So‚ when a metal and a nonmetal react‚ there is an ionic bond formed‚ which means one of them loses electrons while the other gains them. Since this reaction involves the exchange of electrons it is termed as a redox reaction. The oxidation states in a metal- nonmetal are simple
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98.) Consider the unbalanced redox reaction: Cr2O72- (aq ) + Cu(s ) → Cr3+ (aq ) + Cu2+ Balance the equation in acidic solution and determine how much of a 0.850 M K2Cr2O7 solution is required to completely dissolve 5.25 g of Cu. Nitric acid is usually purchased in concentrated form with a 70.3% HNO3 concentration by mass and a density of 1.41 g/mL. How much of the concentrated stock solution in milliliters should you use to make 2.5 L of 0.500 M HNO3? Mass %= Mass Solute/ Mass Solvent + Mass
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word as used in your textbook? A. B. C. D. E. air tap water sea water water toothpaste 2. Select the best statement. A. B. C. D. E. Physical changes may be reversed by changing the temperature. Physical changes alter the composition of the substances involved. Physical properties are not valid characteristics for identifying a substance. Physical properties are mostly extensive in nature. Physical changes are usually accompanied by chemical changes. 3. Select the best
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Skills Determining the reactivity of various metals Testing Relative Oxidizing and Reducing Strengths of Metal Atoms and Ions By observing whether reactions occur between solid metals and metal ions in solution‚ you can determine the order of oxidizing and reducing agents according to strength. Question How can the presence or absence of a reaction provide information about the relative strength of oxidizing and reducing agents? Safety Precautions • Wear goggles‚ gloves‚ and an apron
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Determination of % Composition of Pennies Using Redox and Double Displacement (Precipitation) Reactions Introduction: Oxidation involves the gain of electrons of hydrogen or the loss of oxygen or decrease in oxidation state. If zinc completely reacts with HCL‚ then the theoretical yield of copper should be equivalent to the actual yield. Purpose: In this lab‚ we will determine the percent composition of a modern (post-1982) penny by using a strong acid to react and dissolve the zinc
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IB Chemistry Experiment 4 Composition of a Post-1983 Penny Lab Report Background: Through the use of percent composition one can easily find out how much of a certain element is in a compound or an item such as a post-1983 penny. The experiment will be using HCl a strong acid to dissolve all the zinc inside the outer copper shell. The reaction follows as such; Zn+2HCLZnCl2+H2‚ but there will be no reaction with copper. The portion that will be measured is the mass of copper left after all of
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created. In chemical analysis‚ the amount of an object is determined using a process called titration. According to Petrucci et al.‚ titration is a reaction carried out by the carefully controlled addition of one solution to another. It has several types like acid-base titrations and redox titrations. This experiment focuses on the latter type‚ the redox titration. A redox titration is based on an oxidation-reduction reaction between analyte and titrant (Harris‚2009). It involves the transfer
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CHM151LL Laboratory Report Form Fall 2011 Title: Project 5: SPECTROPHOTOMETRIC ANALYSIS OF A PENNY Date Run: 04/03/2012 Date Submitted: 04/15/2012 Grade: _____________________ Objectives: The purpose of this experiment is to use spectrophotometry to determine the percentage of copper in a copper-clad penny‚ and to determine the thickness of copper layer on the copper-clad penny. Introduction: In the spectrophotometric analysis of a penny lab‚ we will be conducting three
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--Greek proverb Preparing to experiment You will be provided with the following materials: Redox Reactions Reactions involving oxidation and reduction processes are very important in our everyday world. They make batteries work and cause metals to corrode (or help to prevent their corrosion). They enable us to obtain heat by burning fuels--in factories and in our bodies. Many redox reactions are complex. However‚ combustion and synthesis (from elements) are two ordinary examples which
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