Introduction Enthalpy change‚ ΔH‚ is defined as the heat output of a system as it goes through a reaction under constant pressure. It is an important aspect of thermochemistry‚ which is the study of energy changes during a chemical or physical reaction . When we calculate enthalpy change‚ we always assume that the pressure is constant. We are able to calculate enthalpy change numerous ways‚ notably by the increase in heat‚ Q‚ given by an exothermic reaction or the heat absorbed by an endothermic
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Thermodynamics- Enthalpy of Reaction and Hess’s Law December 5‚ 2011 Kylie Case‚ Emma McKee‚ Rebecca Smith Purpose: In this lab‚ the purpose was to verify Hess’s Law. Theory: Four main topics were covered during this experiment including enthalpy of reaction‚ heat of formation‚ Hess’s Law‚ and calorimetry. The first being enthalpy of reaction‚ ΔHrxn‚ which is the heat or enthalpy change for a chemical reaction. The energy change is equal to the amount of heat transferred at a constant
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slide #1. Slide #1: 1. With the wooden applicator stick‚ dip the end into the blood and place a tiny drop onto slide #1 and put cover slip over it. Slide#2 1. Place 1 drop of 0.9% NaCl with the drop of blood (use the filter paper to absorb excess liquid). 2. Add a cover-slip and use filter paper to absorb extra liquid (if necessary). 3. Observe cells under 40X then IOOX and then high power (400X). 4. The sheep blood in an isotonic solution Slide#3 1. Place 1 drop of 10% NaCl solution onto
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Introduction The reaction rate of a chemical reaction is determined as the change in the concentration of a reactant or product over the change in time. [1] The rate of a reaction is determined by experiment. Many factors influence the rate of a reaction: the nature of the reaction‚ concentration‚ pressure‚ temperature‚ and surface area‚ presence of catalyst and intensity of light. [2] For a chemical reaction‚ the rate law or rate equation is a mathematical expressed equation that links the reaction rate with
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Hess Law Lab DESIGN Aspect 1: Problem: What is the molar enthalpy of formation of magnesium oxide? Variables: Manipulated: None Responding: None Controlled: Isolation of calorimeter‚ concentrations of substances involved. Aspect 2: Background Information: Assumptions: Specific heat capacity of water‚ we assume that the acid has the same qualities as water including heat capacity‚ and we assume the enthalpy of formation for magnesium oxide from the data booklet for theoretical
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Evaluating An Enthalpy Change That Cannot Be Measured Directly. Dr. Watson. Introduction. We were told that sodium hydrogencarbonate decomposes on heating to give sodium carbonate‚ water and carbon dioxide as shown in the equation below:- 2NaHCO3(s)--------> Na2CO3 (s) + H2O (l) + CO2 (g) = DeltaH1 This was given as deltaH1 and we had to calculate as part of the experiment. This however cannot be measured directly‚ but can be found using the enthalpy changes from two other reactions. These being
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06.03 Calorimetry: Lab Report Before You Begin: You may either copy and paste this document into a word processing program of your choice or print this page. Part I The Dissolving of Solid Sodium Hydroxide in Water Procedure: 1. Measure out approximately 200 mL of distilled water and pour it into the calorimeter. Stir carefully with a thermometer until a constant temperature is reached. Record the volume of water and the constant initial temperature of the water on your data table.
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Acids and Bases Are Everywhere Every liquid you see will probably have either acidic or basic traits. Water (H2O) can be both an acid and a base‚ depending on how you look at it. It can be considered an acid in some reactions and a base in others. Water can even react with itself to form acids and bases. It happens in really small amounts‚ so it won’t change your experiments at all. It goes like this: 2H2O --> H2O + H+ + OH- --> H3O+ + OH- See how the hydrogen ion was transferred? Most of the
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Acid-Base Titration Objectives: 1. To titrate a hydrochloric acid solution of unknown concentration with standardized 0.10M sodium hydroxide. 2. To utilize the titration data to calculate the molarity of the hydrochloric acid. Materials: See handout for more info. Procedure: See handout for more info. Data and Calculations: Table 1: Volume of NaOH Required to Neutralize 10.00mL of Unknown HCl Molarity of NaOh | Trial 1 | Trial 2 | Trial 3 | Trial 4 | Initial Volume of NaOH(mL)
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project is to determine whether river water or lake water is cleanest as it relates to tap water. The independent variables being tested in this experiment are the different waters being tested which are river water‚ lake water‚ and tap water‚ which is the control. The dependant variable is which of the three waters are the cleanest as it relates to unfiltered tap water. The purpose of this experiment is to determine what the different aspects of the three types of waters are and how that relates to cleanliness
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