Name Calculated values of AHC (joules): Separations of Food Dyes by Paper Chromatography 9- Date Original value calculated for ATC New value calculated for ATC +0.4 °C J J Now compare the new value to the old (first) value by calculating the relative percentage uncertainty in AHc: relative percentage uncertainty AH(new) AH(original) AHC(original) × 100% = Typically, this relative percentage uncertainty is about 3%. Also keep in mind that our neglect of the heat losses to the calorimeter biases our results to values that are about 3% too low. 2. The enthalpy of dissociation of water. The H2SO4 and NaOH reactants and the NaHSO4 product in part 3 actually exist as dissociated ions, so the equation H3O+ HSO4 + Na + OH → Na+ + HSO4 + 2 H₂O better represents the reaction (the total ionic equation). Write the equation that represents the net ionic equation by canceling out the spectator ions (those that appear on both sides of the total ionic equation). Net ionic equation: This net ionic equation represents the reaction of a strong acid and a strong base in water. Based on this result, and the measured AH reaction/mol from part 3, what is the approximate enthalpy change for the dissociation of water into H₂O' and OH lons? (Hint: How is the net ionic reaction above related to the reaction below?) 2 H2O → H3O+ (aq) + OH(aq) Estimated AHreaction kJ/mol (Note: This is only an approximate estimate because HSO4 ion is nearly undissociated in 1 M H2SO4 but is about 14% dissociated in 0.5 M NaHSO4 because the enthalpy change for this partial dissociation is included in our measurements. Compare your estimate for the dissociation of water with the literature value of about +57 kJ/mol.) 202