Substance H2O H2O H2O R134a R134a T‚ oC 250 105 340 Substance H2O H2O H2O R134a R134a P‚ kPa 1800 v‚ m3/kg u kJ/kg x Phase description 1 0.025 50 8200 360 2000 T‚ oC 250 105 340 5.82 50 P‚ kPa 1800 120.8 8200 360 2000 v‚ m3/kg 0.125 1.42 0.02806 0.025 0.0009013 * quality not defined 2645 u kJ/kg 2685 2512 2715 134.6 121.4 X * 1 * 0.4322 * Phase description Superheated vapor Saturated vapor Superheated vapor
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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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calorimeter) to determine the heats of reaction for Magnesium (Mg) with Hydrochloric Acid (HCl) and Hydrochloric Acid with Magnesium Oxide (MgO). Then using mathematical formulas we were able to calculate the heat formation of MgO‚ which is measured in kJ/Mol. Since both reactions are in dilute water solutions of HCl it was necessary to know the heat capacity of water‚ but because some heat would be transferred to the calorimeter whose heat capacity was unknown‚ we had to record a correction factor
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contains 40 people is to be air conditioned with window air conditioning units of 6 kW cooling capacity. A person at rest may be assumed to dissipate heat at a rate of about 360 kJ/h. There are 10 light bulbs in the room‚ each with a rating of 100 W. The rate of heat transfer to the classroom through the walls is 15‚000 kJ/h. If the room air is to be maintained at a constant temperature of 21oC‚ determine the number of air-conditioning units required. In this problem‚ we define the system to
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Lecture 12 Chapter 6 6.1 Thermochemistry: Energy & units (p.227) From observation we know‚ that - some chemical reactions begin as soon as the reactants come into contact with each other (precipitation reactions) - some reactions are slow or even so slow at room temperature that even lifetime is not enough to observe a measurable change (rusting of iron‚ tarnishing silver) Also‚ almost all chemical reactions involve exchange of heat (or energy): in combustion reactions
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Experiment B2‚ Heats of Combustion – The Bomb Calorimeter. Objectives: To calibrate a bomb calorimeter by the combustion of benzoic acid. Then to use the calibrated calorimeter to measure the heat of combustion of naphthalene and calculate the heat of formation of naphthalene. Theory: q = C.ΔTBA C = q / ΔTBA Moles = mass / Mr ΔŪ = ΔU / moles ΔHoc‚298 = ΔŪoc‚298 + PDV = ΔŪoc‚298 + RTΔn C10H8 (s) + 12O2 (g) 10CO2 (g) + 4H2O (l) ΔHoc‚298 = - 1
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In this investigation I will be burning alcohol ’s to heat up a can of water. I will be burning four alcohol ’s‚ methanol‚ ethanol‚ propanol and butanol. The aim is to find out how much energy is produced when burning these alcohols. Alcohol ’s react with oxygen in the air to form water and carbon dioxide. The reaction that is involved in burning alcohols is exothermic because heat is given out. From this reason the reactant energy is higher than that of the product. The energy is given out when
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Coupled Reactions ABSTRACT A way to drive a non-spontaneous reaction forward is by coupling it with another reaction that is highly spontaneous‚ resulting to a spontaneous overall reaction. In this study‚ since the extraction of C(s) from CO2(s) is a non-spontaneous process‚ it was coupled with the oxide formation reaction of Mg‚ a reaction with high spontaneity‚ so that the process of the extraction of C(s) would proceed. The reactions and products which were a mix of black and white
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Experiment 1: Calorimetry C.L. Mercado institute of chemistry‚ college of science university of the philippines‚ diliman quezon city‚ philippines date performed: November 16‚ 2012 instructor’s name: Irina Diane V. CastaÑo _________________________________________________________________________________________________________________________ introduction Chemical reactions absorb or release heat. One way to measure this is by using a homemade calorimeter. The calorimeter used
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Assignment 1. Questions from chapters 1 and 2 of McMurry and Fay Question numbers are from the fourth edition. Chapter 1. Chemistry: Matter and Measurement 1 1.1 1.2 1.3 (a) Cd (b) Sb (a) silver (c) Am (c) rhenium (d) cesium (e) argon (f) arsenic (b) rhodium (a) Ti‚ metal (d) Sc‚ metal (b) Te‚ semimetal (e) At‚ semimetal (c) Se‚ nonmetal (f) Ar‚ nonmetal 1.4 1.5 The three Acoinage metals@ are copper (Cu)‚ silver (Ag)‚ and gold (Au). (a) The decimal point must be shifted
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