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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Measuring the Enthalpy change of combustion Abstract This simple experiment is carried out to show the difference in the enthalpy change of combustion between two fuels‚ hexane and methanol. These fuels are individually weighed before and after used as heat source to heat water in a calorimeter. The result is used to find out amount of heat transferred by the fuel‚ amount of fuel used and the enthalpy change of combustion. Introduction Enthalpy change of combustion is the enthalpy change when
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Calorimetry: Enthalpy of Neutralization Introduction: The purpose of this lab experiment was to determine the molar concentration of the unknown HCl by using a coffee cup calorimeter. A coffee cup calorimeter is made of Styrofoam cups with a thermometer that is placed from the top and into the calorimeter to measure the temperature as the reaction happens. The Styrofoam cup used for the calorimeter creates an isolated system as it acts as a heat insulator between the cup and the surrounding
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of MgO‚ using a calorimeter and determining the enthalpy of two reactions. Applying Hess’ law we were able to determine the standard heat formation of MgO. Introduction Energy exchanged in a chemical reaction can either be in the form of heat or light. If light is involved a glow is seen‚ if heat is involved the temperature of the system will change(lab manual page 35). The amount of heat exchanged under constant pressure is called the enthalpy change‚ this can either be endothermic or exothermic
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Yr: 2014 Yr: 2013 Remarks 1.1 Profitibality Ratio 1.1.1 ROE= x 100 = 10.71% x100 = 10.30% Higher the better 1.1.2 ROTA= x100 = 18.27% x100 = 19.45% Higher the better 1.1.3 GPM= x100 = 71.67% x100 =70.35% Higher the better 1.1.4 OPM= x100 =28.72% x100 =29.79% Higher the better 1.1.5 NPM= x100 =43.48% x100 =39.46% Higher the better 1.1.6 NPM= x100 =38.74% x100 =35.04% Higher the better 1.2 Asset Utilisation 1.2.1 TA TURN= x100 =18.27% x100 =19.45% Higher the better 1.2.2
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Sample Calculations I-Beam (S8x18.4) Dimensions: D= 8 in; h= 7.148 in; bf= 4.001 in; tw= 0.271in; tf= 0.426in; L (length of the beam) =18.4 in I= (bf*D3 – h3 (bf – tw))/12= 57.6 in4; E (Referenced value of Young’s modulus) = 29X106 psi Theoretical Strain: ε= σ/E= (M*y)/(E*I) P = load a = distance from support to the applied load (48 in) y = distance from neutral axis to the extreme element in y-direction The sing in the theoretical strain (±) determines if the strain is in compression
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3rd‚ 2009 Lab Report #3: Copper Cycle Abstract: The purpose of the experiment is to cycle solid copper through a series of five reactions. At different stages of the cycle‚ copper was present in different forms. First reaction involves reaction between the copper and nitric acid‚ and copper changed from elemental state to an aqueous. The second reaction converted the aqueous Cu2+ into the solid copper (2) hydroxide. In the third reaction Cu(OH)2 decomposed into copper 2 oxide and water when heated
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CALCULATIONS Determining the amount Limiting Reagent used. nlimiting reagent = Molarity x Volume or Mass / Molar Mass Example: Limiting reagent is 5mL of 1.0 M HCl nlimiting reagent = Molarity x Volume nlimiting reagent = (1.0 [mol/L]) x 0.005 [L]) = 0.005 mol Determining the qrxn and qcal. qrxn + qcal = 0 -qrxn = qcal qrxn = ΔHrxn x nlimiting reagent qcal = Ccal ΔT qrxn = - Ccal ΔT + mcsolid ΔT (note: only if there is a precipitate formed in the reaction)
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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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Determining the enthalpy change for the thermal decomposition of potassium hydrogen carbonate into potassium carbonate. Controlled Variables: 1. Volume of HCl ± 0.5 cm3 (± 2%) 2. Concentration of HCl‚ 3. Same mass of K2CO3 and KHCO3 within specified ranges of 2.5 – 3.0g and 3.25 – 3.75g respectively 4. Same calorimeter used i.e. polystyrene cup is used in this experiment 5. Same thermometer will be used ± 0.10K 6. Same source of K2CO3‚ KHCO3 and HCl Raw Data Results: The raw
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