15.2 Born-Haber Cycle Our calculations of enthalpies so far have involved covalent substances. Now we need to look at the enthalpy changes involved in the formation of giant ionic lattices. Lattice enthalpy is defined as either the: ’the enthalpy change that occurs when one mole of a solid ionic crystal is broken into its ions in the gaseous state‚ at standard temperature and pressure. Because all the bonds in the ionic lattice are broken‚ it is an endothermic process‚ ∆H is positive. ’ The
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experiment‚ we us naphthalene as a fuel in bomb calorimeter which naphthalene powder is turned to pellet using pellet press. The fuel is burnt at constant volume condition in a high pressure container (the bomb). The whole bomb‚ pressurized with excess of oxygen. The mass of iron wire‚ ma =0.02g. The mass of naphthalene pellet with iron wire‚ mb =0.38g. The bomb is submerged in 850g of water and the initial temperature of calorimeter state temperature of calorimeter water before burning the fuel‚ Ti is
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molar enthalpy change of a neutralization reaction Principle H2SO4(aq)+2NaOH(aq)=Na2SO4(aq)+2H2O(l) The reaction is a exothermic reaction‚ when the heat released by it is absorbed by water‚ the temperature of the water increases. The heat produced by the reaction can be calculated if it is assumed that all the heat is absorbed by the water. Heat change of reaction=-heat change of water =-mH2O×cH2O×△TH2O As the water has gained the heat produced by the reaction‚ the heat change of reaction is negative
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* . Introduction Endothermic reactions are accompanied by the absorption of heat. The dissolving of ammonium nitrate in water is an example of an endothermic reaction. The solution resulting from this mixture is colder than either the ammonium nitrate or the water. This is the simple explanation of what happens in an instant ice pack. The more detailed information will be discussed in the following paragraphs. Cold Packs Most cold packs come with a fabric cover made to absorb condensation and
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LAB OF ENTHALPY CHANGE IN COMBUSTION Objective: Determine the Enthalpy change of combustion ΔHc of three different alcohols. Methanol‚ Ethanol and Isopropilic acid. Procedure: 1. Fill the spirit micro burner with Ethanol and weight it 2. Pour 100 cm3 of water into the aluminum cup 3. Arrange the cup a short distance over the micro burner 4. Measure the temperature of water 5. When the temperature of the water has risen by 10°C‚ record the temperature. 6. Reweight
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between the end point and the equivalence point is that the end point is just an indicator of when the color changes and titration stops. The equivalence point is when the H+ ions are neutralized by OH- ions‚ which occurs when both are used up in the reaction causing the pH to be 7. The molarity of NaOH from the indicator was exactly .500 M‚ but the molarity for the equivalence point from the second derivative was .688 M. This resulted in a range of roughly 27.3%‚ which is way over the 15% error mark
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Determination of Rate and Order of a Reaction Results This experiment used a spectrometer to find the wavelength with maximum absorbance in a green food coloring solution. For this particular solution the wavelength was 629.7 nm. The system was then calibrated to that and was set to measure the food coloring and bleach solution. The measured visible light absorbance of the mixed solution was collected over a time of 200 seconds and eight points were then selected and placed into the Absorbance
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substance within the system”. Apparatus: Two (2) similar Calorimeters: a Thermometer: a Measuring Cylinder: a Bunsen burner: a Tripod: an Asbestos Gauze Cork Mat. Procedure: * The tripod and Bunsen burner were set up as shown in fig. 1 * Using the measuring cylinder 50gm of water was measured and poured into (1) one calorimeter labeled A‚ and 100gm was also measured and poured into the other calorimeter labeled B. * The calorimeter containing the 50gm of water was set on the cork mat
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The movie that we watched was about reviving a person from the dead. This is said to be done in the future but they had already started researching how to use ice as a power to revive a clinically dead person. They used ice as a method to preserve a body and now they are planning on how to revive a person through the use of nanotechnology that can repair all the cells that were ruptured n the freezing process. The technology that they were referring in the movie is called Cryonics. This Cryonics
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Task 1: Assessment criterion 2.1 Determine the enthalpy change for the reaction (ΔHfθ) between zinc and copper sulphate solution‚ giving full practical details. Aim To determine the enthalpy change for the reaction between zinc and copper sulphate. Zn (s) + CuSO4 (aq) ZnSO4 (aq) + Cu (s) Introduction In the study of energy (thermodynamics) the system refers to the reacting chemicals (zinc and copper sulphate solution) and the surroundings is everything else (atmosphere
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