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: volume). After
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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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Molar Volume of a Gas Objective: The objective is to determine the volume‚ of one mole of hydrogen gas at STP using experimental data‚ known mathematical relationships‚ and a balanced chemical equation. Theory: The goal of this lab is to find the volume of one mole of hydrogen at STP. The experimenters will be working with hydrochloric acid and magnesium to find the objective. The acid in this lab will react to the magnesium and cause the water in the eudiometer to rise because of the reaction
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Molar Mass of a Volatile Liquid There are several ways to find the molar mass of a substance. One way‚ if the substance is a gas‚ is to use the Ideal Gas Equation to find molar mass. The standard equation reads PV=nRT where “n” is the number of moles present‚ “P” is the pressure (which is obtained by reading the barometric pressure of the room with the class barometer)‚ “V” is the volume of the gas‚ “R” is the universal constant‚ and “T” is the temperature of the gas. The experiment’s objective
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Capacity for a 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
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constant. Use potassium chloride with a known conductivity as a standard solution. The conductivity measurements are not appropriate to compare between two electrolyte solutions because of the high dependant towards solution concentration. The molar conductivity (Λm) measurements would be more appropriate. Λm could be determined from the conductivity value: [pic] where C is the electrolyte concentration In mol/L. the unit is S cm2mol-1 If the dependant of conductivity towards concentration
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10-3 mol 3. Molar mass – mass in grams of one mole of a substance. Example 3-5 page 76 4.62 g Na3PO4 Molar Mass Na3PO4 = (22.9898 gNa X 3) + (30.9738 gP) + (15.9994 gO X4) = 163.9408 g per mol Na3PO4 Moles Na3PO4 = 4.62 g X 163.9408 g/ mol = 2.818 X 10-2 mol Na3PO4 Moles Na = 2.818 X 10-2 mol Na3PO4 X 3 mol Na / mol Na3PO4 = 8.45 X 10-2 mol Na Na+ ions = 8.45 X 10-2 mol Na X (6.022 X 1023) = 5.08 X 1022 ions C. Solutions and Their Concentrations 1. Molar Concentration
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chemical reaction occurs in which the system produces heat it is exothermic (it feels hot) Under conditions of constant pressure the heat absorbed or released is termed enthalpy (or "heat content"). We do not measure enthalpy directly‚ rather we are concerned about the heat added or lost by the system‚ which is the change in enthalpy (or ΔH The quantity of heat gained or lost by a system‚ ΔH‚ is dependent upon‚ the mass‚ m‚ of the system: the more massive an object the more heat needed to raise its
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a coffee cup calorimeter was used to measure the temperature readings of a neutralization reaction and magnesium oxide‚ MgO. Calorimetry is used to measure amounts of heat transferred to or from a substance.2 The difference of temperatures was used to calculate the heat energy given off by each sub-reaction. These values were solved by using Hess’s Law which determined the overall enthalpy changes of the neutralization reaction and MgO formation. Hess’s Law states that the heat evolved or absorbed
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Grant 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
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