postlab11 - already been calculated. The first reaction was...

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Sam Eichenblatt Lab 11 Chem 1310 A2 The first part of the experiment was, using the change in temperature when warm and room temperature water was added, calculating the Heat Capacity of the calorimeter. Using the equation –q(hot water)=q(cold water)+q(cal), we were able to limit the unknowns to only the heat capacity of the calorimeter(C(cal)). Water was heated and the initial temperature was taken before it was added to the room temperature water. After the two different waters were added they were left to reach the equilibrium temperature, and once that was reached the final temperature was taken. After that deltaT was plugged into the equation which only left C(cal) left after substituting q=c*m*deltaT into the original equation. This was done in two trials and the average C(cal) was taken and used later in the lab. In the second part of the lab the change in temperature was recorded from two different reactions in the calorimeter from the previous experiment. We used the same calorimeter because the C(cal) had
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Unformatted text preview: already been calculated. The first reaction was between magnesium and hydrochloric acid. There was a change in temperature of 6.5 C in this reaction and using this and the equation deltaH=-[qcal+qwater] the enthalpy was calculated. The deltaH was equal to -2.864 KJ. Then the enthalpy was calculated for the reaction between magnesium oxide and hydrochloric acid using the same method. The change in temperature was 6 C and the enthalpy was -2.643 KJ. After the two enthalpies were calculated, using the enthalpy of a third water equation was given(-285.84 KJ). Using the three enthalpies and flipping equations the enthalpy of the reaction Mg+(1/2)O2 MgO was found to be -286.02 KJ. Some possible errors for this experiement could have been misreading of the thermometer in any parts of the experiements. Also wrong weights or volumes of MgO, Mg, and HCl could have changed the final enthalpy values....
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This note was uploaded on 09/07/2010 for the course CHEM 1310 taught by Professor Cox during the Fall '08 term at Georgia Tech.

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