Hess Law Lab Report

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LAB REPORT ON VERIFICATION OF HESS’S LAW Our purpose of doing this lab was to prove the Hess’s law correct. Hess’s law suggests that the enthalpy change of a reaction must be equal to the sum of the enthalpy changes of the related reactions which lead to the original reactions. The following are the reactions at the lab; 1) NaOH ( s) NaOH (aq) 2) NaOH (aq) + HCl (aq) NaCl (aq) + H2O (l) 3) NaOH (s) + HCl (aq) NaCl (aq) + H2O (l) As explained before, Hess’s Law states that the enthalpy change of reaction three (ΔH3) should be equal to the sum of the enthalpy changes of the first two reactions ( ΔH1 + ΔH2 ). As seen at the equations, the solid NaOH dissociates into its ions, after that it is neutralized by HCl. DATA…show more content…
Only random errors were made. The literature value for the enthalpy change of the last reaction which was provided by our teacher is -97 kJ mol-1. Agreeing this value, our result can be considered accurate. As told at the beginning of this lab report, our aim of this experiment was to test the validity of Hess’s law which suggests that the enthalpy change of a reaction must be equal to the sum of the enthalpy changes of the other reactions that relate to the original reaction. Our result achieved from this experiment is the simple proof of Hess’s Law’s validity. Even though the result of an experiment is accurate and matches the literature value, it does not mean that there were no mistakes made. As the difference of the percentage uncertainty and the percentage error suggests there were random errors made. First of them was the heat energy lost to the surrounding environment during the experiment process taking place. This caused the recorded highest temperature to be smaller than the actual highest temperature that was meant to reach. This could have been prevented by adding in more and perfect
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