Germain Henri Hess (August 7‚ 1802–November 30‚ 1850) was a Swiss-born Russian chemist and doctor who formulated Hess’s Law‚ an early principle of thermochemistry. Born in Geneva‚ Switzerland‚ his father was an artist and in 1805 moved the family to Russia to find work. Beginning in 1822‚ Hess studied medicine at the University of Tartu. He qualified as a physician in 1825. Hess turned to chemistry after a meeting with Jöns Jakob Berzelius‚ the famous Swedish chemist‚ and went to Stockholm University
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Heats of Reaction Lab Report Purpose: To measure the heats of reaction for three related exothermic reactions and to verify Hess’s Law of Heat Summation. NaOH(s) ( Na+(aq) + OH-(aq) ΔH = -10.6kcal/mol NaOH(s) + H+(aq) + Cl-(aq) ( H2O + Na+(aq) + Cl-(aq) ΔH = -23.9kcal/mol Na+(aq) + OH-(aq) + H+(aq) + Cl-(aq) ( H2O + Na+(aq) + Cl-(aq) ΔH = -13.3kcal/mol Background: Energy changes occur in all chemical reactions; energy is either absorbed or released. If energy is released in
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Thermodynamics – Enthalpy of Reaction and Hess’s Law I. Purpose The purpose of this lab is to verify Hess’s Law through the three reactions of NaOH and HCl‚ NH4Cl and NaOH‚ and NH3 and HCl. The sum of the enthalpies of the first two reactions should equal the enthalpy of the third reaction. II. Background Hess’s Law is used to determine the enthalpy of a reaction from adding two or more preceding reactions. To determine the enthalpies of certain chemical reactions‚ the change in must
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Lab 3: Reaction Order and Rate Laws Name: Student Lab Partners: None Date of Experiment: 16 March 2014 Location: My House Course Number: CHE112 Abstract: When combining compounds‚ there are always two roles considered in the reaction. These are reactants and products. Reactants are the initial compounds before mixing. The products are synonymous with the term byproduct‚ or what remains when the reaction occurs. For example‚ Sodium (Na+) and Chlorine (Cl-)
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physics and chemistry‚ heat is energy transferred from one body to another by thermal interactions. The transfer of energy can occur in a variety of ways‚ among them conduction‚radiation‚ and convection. The SI unit of heat is the joule. Heat can be measured by calorimeter‚ or determined indirectly by calculations based on other quantities‚ relying for instance on the first law of thermodynamics. In calorimeter‚ the concepts of latent heat and of sensible heat are used. Latent heat produces changes of
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HEAT GENERATED IN APPLIANCES Why do some appliances produce more heat than the others? Most appliances with high power rating are heating appliances.The heating appliances has a heating element like resistors. The resistorsconvert electrical energy into light and thermal energy . It depends on the resistance of material if how much heat can be produced from electricity. Those devices who produced heat‚ the Nichrome wire is an element who is responsible for heating . when we say nichrome
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well known Moore’s Law. c. Relevance Without the prior knowledge of the history of how computers or integrated circuits were designed and produced how can a student such as a computer scientist undergrad say that he knows what he is doing if he does not very well know the very building blocks that make up his career. It is very important to understand the small details of the subject matter before conquering enormous problems of the same ordeal. d. Flaw Moore’s Law still holds true that
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Reaction Order and Rate Law Name Data‚ Calculations‚ and Questions A. Calculate the initial and final concentrations as needed to complete Tables 1 and 2. Data Table 1: Varying the Concentration of 1.0 M HCl | | | | |Concentrations | | |# Drops |# Drops |# Drops |Initial
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volume). 3. [10 points] The following reaction is found to be first order in A: A −→ B + C If half of the starting quantity of A is used up after 56 seconds‚ calculate the fraction that will be used up after 6.0 minutes. 4. [15 points] The rate law for the decomposition of ozone to molecular oxygen 3 O3 (g) −→ 3 O2 (g) is rate = k [O3 ]2 . [O2 ] The mechanism for this process is k1 O3 O + O2 k−1 k 2 O + O3 −→ 2 O2 Derive a rate law from these elementary steps. Clearly
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Erica Chan Sinh Nguyen Dat Nguyen Wed 2:00-5:00 02/19/2014 OHM’S LAW I. Purpose The purpose of this lab is to help understand how voltage‚ current and resistance are closely related to one another. The outcome from this lab is to be able to differentiate when to use ohmmeter and voltmeter for the individual circuit. II. Theory Ohm’s Law states that the electric current through a material is directly proportional to the voltage across a piece of material (such as wire) while the resistance is held
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