Thermochemistry: An Ice Calorimeter Determination of Reaction Enthalpy D. F. Nachman 6/23/2010 Abstract: An ice calorimeter was used to study the reaction of magnesium metal and 1.00M sulfuric acid solution: Mg(s) + H2SO4(aq) →MgSO4(aq) + H2(g). We found the experimental molar enthalpy of reaction to be ΔH = –355 ± 17 kJ/mol at 0°C‚ 24% lower than the textbook value of ΔH° = –466.9 kJ/mol‚ reported at 25°C. Introduction Whether a chemical reaction occurs spontaneously or is driven by an outside
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The thermal decomposition of nitrates – ‘writing with fire’ 31 A message is written on filter paper with a solution of sodium nitrate and is then dried‚ rendering it invisible. Applying a glowing splint to the start of the message makes the treated paper smoulder and the message is revealed as the glow spreads its way through the treated paper. Lesson organisation The demonstration takes about 10 -15 minutes. It could be a student activity‚ but with a large class it will need a well
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Lab 5 DECOMPOSITION (Nov 2‚ 2011) Introduction: Decomposition is the breakdown of organic material into its smaller molecules and elements. (This term is generally considered as a biotic process but one may find it also used to describe an abiotic process‚ e.g.‚ due to weathering.) The decomposing organisms may use the release of elements for nutrients and by breaking apart the carbon-carbon bonds in organic matter this can release energy for them. These smaller molecules and nutrient elements
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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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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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investigate the effect of the mass of magnesium dioxide used on the speed of the reaction of 2H2O2(aq) 2H2O(l) + O2(g). I hypothesize that the speed of the reaction is proportional to the rate of decomposition. Independent Variable The mass of MnO2 used Dependent Variable The rate of decomposition through the amount of mass lost Controlled Variables Environment of the experiment Stay in the same place to carry out the experiment and finish the experiment as fast as possible in case of a sudden
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Chemistry Write-Up The Thermal Decomposition of Sodium Hydrogen Carbonate Aim: When Sodium Hydrogen Carbonate (NaHCO3) is heated‚ Carbon dioxide and water are given off to leave a white powder. The aim is to find the equations for this reaction. Hypothesis: The experiment will prove which of the equations below is true. It will tell us whether Sodium Carbonate is produced or Sodium Oxide. 2NaHCO3 Na2CO3 + CO2 + H2O 2NaHCO3 Na2O + 2CO2 + H2O Variables: Independent: Original
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Chemistry Internal Assessment: Determining the Enthalpy Change of a Displacement Reaction AIM: To determine the enthalpy change for the reaction between copper(II) sulfate and zinc. BACKGROUND THEORY: Bond breaking is endothermic while bond forming is exothermic. The reaction between copper(ll) sulfate and zinc is exothermic as the energy required to form the bonds of the products is greater than the energy required to break the bonds of the reactants. In an exothermic reaction‚ heat is
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calculate the enthalpy change of neutralization of the given pairs of acid and base. Theory: When alkali neutralizes an acid‚ a salt and water are formed. Aqueous hydrogen ions‚ H+(aq) from the acid react with the hydroxide ions‚ OH-(aq) from the alkali‚ forming water. Ionic equation: H+ (aq)+OH- (aq) → H2O (l) The identity of the salt will depend on the nature of the acid and alkali used. The combination of H+ and OH- ions in this way releases energy. In this practical‚ the enthalpy changes accompanying
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Plan: Aim: The enthalpy change of combustion of a fuel is a measure of the energy transferred when one mole of fuel burns completely. A value for the enthalpy change can be obtained by using the burning fuel to heat water and using fact that 4.2j of energy are required to raise the temperature of 1g of water by 1oC. In this investigation my aim is to find the enthalpy change of combustion of a number of alcohols so that I can investigate how and why the enthalpy change is affected by the molecular
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