15.2 Born-Haber Cycle Our calculations of enthalpies so far have involved covalent substances. Now we need to look at the enthalpy changes involved in the formation of giant ionic lattices. Lattice enthalpy is defined as either the: ’the enthalpy change that occurs when one mole of a solid ionic crystal is broken into its ions in the gaseous state‚ at standard temperature and pressure. Because all the bonds in the ionic lattice are broken‚ it is an endothermic process‚ ∆H is positive. ’ The
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Speed of Decomposition and Its Factors Purpose The term decomposition is the process of breaking down dead organisms to reuse them. Decomposition allows nutrients in organisms to become free after they die or have become old and they are ready to be used by living plants and animals for their growth. Without decomposition useful nutrients would remain locked inside of a dead organism and it would be very difficult for new life to grow. Most of the nutrients that are essential for the plants
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Determining an enthalpy change of a displacement reaction Aim: To determine the enthalpy change for the displacement reaction between zinc powder and copper (II) sulphate solution. Zn (s) + Cu2+ (aq) → Cu2+ (s) + Zn2+ (aq) Theory: For the displacement reaction‚ an excess amount of zinc powder is added to the measured amount of aqueous copper (II) sulphate. The temperature change over a period of time has to be measured and thus‚ the enthalpy change for the reaction can be measured. The equation
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Introduction The primary objective of this lab is to be able to determine the specific heat of a reaction by using a calorimeter. A calorimeter is a device used to determine the specific heat of chemical reaction or a physical change. The specific heat a reactions is used to refer to the amount of heat that is lost or gained when one gram of a particular substance increases or decreases by one degree Celsius. When a chemical reaction occurs in an open container most of the energy gained or lost
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the Enthalpy of a Chemical Reaction All chemical reactions involve an exchange of heat energy; therefore‚ it is tempting to plan to follow a reaction by measuring the enthalpy change (∆H). However‚ it is often not possible to directly measure the heat energy change of the reactants and products (the system). We can measure the heat change that occurs in the surroundings by monitoring temperature changes. If we conduct a reaction between two substances in aqueous solution‚ then the enthalpy of
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Chemistry Internal Assessment: Determining the Enthalpy Change of a Displacement Reaction AIM: To determine the enthalpy change for the reaction between copper(II) sulfate and zinc. BACKGROUND THEORY: Bond breaking is endothermic while bond forming is exothermic. The reaction between copper(ll) sulfate and zinc is exothermic as the energy required to form the bonds of the products is greater than the energy required to break the bonds of the reactants. In an exothermic reaction‚ heat is
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Nicholas Acevedo Chem 216 Lab T/Th 8-10:50 Mr. Torres January 31‚ 2013 Experiment 2 Kinetics of H2O2 Decomposition Introduction When measuring the rate of a reaction one can measure the rate at which one of the product appears or the rate at which the reactants disappear. The actual rate of a chemical reaction however is dependent on two things; the temperature the actual experiment is performed at‚ and the concentration pertaining to the reactants. The rate of a reaction more often
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Devon Backstrom February 5st 2013 PSU Chemistry 222 – Lab 4 Decomposition of Hydrogen Peroxide Abstract: This lab was designed to observe the decomposition of hydrogen peroxide into it oxygen and water. The equation for this reaction is H202 H2O + +1/2O2 thus by measuring volume and pressure of O2 generated the amount of O2 generated can be calculated which in turn can be utilized to determine the concentration of water already in the H2O2 solution. The results determined that 3.02% of the
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calculate the enthalpy change of neutralization of the given pairs of acid and base. Theory: When alkali neutralizes an acid‚ a salt and water are formed. Aqueous hydrogen ions‚ H+(aq) from the acid react with the hydroxide ions‚ OH-(aq) from the alkali‚ forming water. Ionic equation: H+ (aq)+OH- (aq) → H2O (l) The identity of the salt will depend on the nature of the acid and alkali used. The combination of H+ and OH- ions in this way releases energy. In this practical‚ the enthalpy changes accompanying
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Plan: Aim: The enthalpy change of combustion of a fuel is a measure of the energy transferred when one mole of fuel burns completely. A value for the enthalpy change can be obtained by using the burning fuel to heat water and using fact that 4.2j of energy are required to raise the temperature of 1g of water by 1oC. In this investigation my aim is to find the enthalpy change of combustion of a number of alcohols so that I can investigate how and why the enthalpy change is affected by the molecular
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