energy and heat associated with chemical reactions and/or physical transformations. A reaction may release or absorb energy‚ and a phase may change‚ such as in melting and boiling. Thermochemistry focuses on these energy changes‚ particularly on the system ’s energy exchange with its surroundings. In combination with entropy determinations‚ it is used to predict whether a reaction is spontaneous or non-spontaneous‚ favourable or unfavourable. Chemical reactions can be divided into two based on the
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comparing the average amount of NaOH and HCl needed for Neutralization in each Condition 4. HCl + NaOH H2O + NaOH Already Balanced Conclusion: In Conclusion‚ the effect of increasing the volume of HCl‚ is that the amount of NaOH needed to neutralize HCl is the almost the initial volume of HCl. In Condition 2 Trial 2 the initial volume of HCl was 8.0 mL‚ the substance stayed pink at 16.0 mL‚ so the amount of NaOH needed for neutralization was 8.0 mL. In the other conditions and trials the
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LAB OF ENTHALPY CHANGE IN COMBUSTION Objective: Determine the Enthalpy change of combustion ΔHc of three different alcohols. Methanol‚ Ethanol and Isopropilic acid. Procedure: 1. Fill the spirit micro burner with Ethanol and weight it 2. Pour 100 cm3 of water into the aluminum cup 3. Arrange the cup a short distance over the micro burner 4. Measure the temperature of water 5. When the temperature of the water has risen by 10°C‚ record the temperature. 6. Reweight
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The purpose of this lab is to determine the rate of reaction under different circumstances. Different variables will be manipulated to discover their effects on a particular reaction. Changes in temperature‚ pH‚ and enzyme concentration are examples of factors that have the potential to affect the initial rate of an enzyme catalyzed reaction in a controlled experiment‚ whether it be speeding the reaction up or slowing it down. Part I of the experiment establishes a baseline that can be used to compare
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Determining the unknown concentration of HCl via heat of neutralization of a reaction involving strong electrolytes and weak electrolytes. Myeongwon Lee 20522885 Partner: Frank Wong TA: Afsoon CHEM 120L – Earth Science & Chem 149 Section: 004 Tuesday‚ November 26th‚ 2013 Introduction All chemical changes are accompanied by change in energy and this energy is in form of heat. The energy change of a reaction that happens at constant pressure is defined as heat of reaction or enthalpy change and the
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Calorimeter and of the Enthalpy of an Acid-Base Reaction Abstract The purpose of this lab was to first‚ determine the specific heat capacity of a homemade calorimeter‚ and second‚ to calculate the enthalpy of reaction for an acid-base reaction between 6M KOH and 6M HNO3. To determine the specific heat capacity of the calorimeter‚ two differing temperatures of water were measured and volume was measured and mixed within the calorimeter. The enthalpy of reaction for an acid-base reaction was found by
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Heat of Neutralization Lab Objective: The objective of this lab was to measure‚ using a calorimeter‚ the energy changes accompanying neutralization reactions. Background: Chemical changes are always accompanied by a change in energy‚ typically as heat. If the reaction releases heat (ΔH < 0) then the reaction is exothermic. If the reaction absorbs heat (ΔH > 0) then the reaction is endothermic. The quantity of heat is measured experimentally by having the reaction take place in an insulated container called a
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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
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Abstract This lab is performed in order to determine the total energy in a reaction between zinc and hydrochloric acid. The reaction is done twice‚ once to measure the heat of the reaction and again to determine the work done in the system. This is because Enthalpy equals heat plus work (∆H= ∆E+W). Heat and work can be broken down further into separate components so the equation used in lab is ∆H=mc∆T + PV. Many calculations are used in the lab to find out what cannot be measured directly (ex:
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Enthalpy‚ represented by the sign ∆H in kJ/mol‚ is the heat change in a reaction. It shows whether how much heat is released or absorbed during the reaction. If the reaction is endothermic‚ the enthalpy would be positive and if the reaction is exothermic‚ the enthalpy would be negative. During a chemical reaction‚ which consists of breaking and creating bonds‚ heat is either absorbed or released. In this lab‚ the reaction uses the disassociation of an ionic compound ammonium nitrate shown in the
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