DETERMINATION OF ENTHALPY CHANGE OF NEUTRALIZATION IA Criteria Assessed: DCP CE MS Introduction When an 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 alkali‚ forming water. The identity of salt will depend on the nature of the acid and alkali used. H+(aq) + OH- (aq) → H2O(L) The combination of H+ and OH- ions in this way releases energy. In this practical‚ the enthalpy changes accompanying
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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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KINETICS OF THE ACID DECOMPOSITION OF THIOSULFATE Aqueous solutions of thiosulfate‚ S2O32-(aq) are stable if neutral or basic‚ but decompose quickly when the thiosulfate is dissolved in acid according to the equation: Sulfur dioxide is a gas at room temperature‚ but is very soluble in water. Sulfur‚ a water insoluble solid‚ forms a colloidal suspension. As a result‚ the solution first becomes cloudy and then opaque. We can take advantage of the developing opacity of the reaction system to do a
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Rate of Decomposition of Calcium Carbonate Theory Calcium carbonate‚ CaCO3‚is one of the most abundant minerals on the Earth. More than 4% of the Earth’s crust is composed of calcium carbonate. It is a major component in limestone‚ marble‚ seashells‚ bedrock‚ etc. Limestone and marble have been among the most widely used building materials for more than 5 000 years‚ from the pyramids in Egypt to the Parthenon in Greece and the Taj Mahal in India. In many places‚ limestone is also the foundation
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Measuring the enthalpy change of vaporisation of water You should attempt this part of the activity even if you have not seen the demonstration of the practical. 1. Calculate a value for ∆Hvap for water in KJ mol-1 using the data from the demonstration. Also‚ calculate ∆Hvap from the following data gathered by a student; 8100 J were needed to distil 2.95g of water. a) Explain why the boiling tube was surrounded with expanded polystyrene (or other similar insulation)‚ but the condenser was left
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Factors affecting the catalytic decomposition of Hydrogen peroxide Please refer to the additional files for tables/graphs. Aim- The purpose of this investigation is to investigate how certain factors affect the catalytic decomposition of Hydrogen peroxide. I will investigate the effect of altering the mass of catalyst used on the rate of the decomposition of Hydrogen peroxide. Introduction- The decomposition of Hydrogen peroxide is a process by which Hydrogen peroxide decomposes into water and
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From the experimental data and through its analysis‚ the enthalpy of combustion for the five alcohols were determined; methanol‚ ethanol‚ propanol‚ butanol‚ and pentanol. As the line of best fit in the graph suggests‚ the enthalpy of combustion increased as the sizes of the molecules increased. This was predicted in the hypothesis and proves it to be correct. As seen on the graph‚ the enthalpy of combustion increases from 140kJ/mol for methanol‚ which has the smallest molecular mass‚ to 530kJ/mol
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Vapor Pressure and Enthalpy of Vaporization of Water 1/9/12 Emily Toy Lab Partner: Zack Ronnei Instructor: Ms. Olsen‚ AP Chemistry Purpose: The purpose of this lab is to find the vapor pressure of water at temperatures between 50oC and 80oC. Procedure: 1. Take a10 mL graduated cylinder and fill it with 7 mL of water. 2. Next fill a 1000 mL beaker ¾ full with water. 3. Cover the graduated cylinder by putting your finger on top and place the cylinder in the 1000 mL beaker. Make
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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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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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