1# How does the enthalpy of neutralisation vary for different sodium salts? 2 3## Method 4 5The calorimeter was first calibrated with 80.0 mL of deionised water. The water was stirred as it was heated, and the average voltage and current draw were recorded for calculation of the calibration constant. 6 7After emptying and rinsing the calorimeter, 40.0 mL of 1.0 M NaOH was added to the calorimeter and its temperature recorded. 80.0 mL of 1.0 M HCl was then addedd and its temperature also recorded. Power was applied to the calorimeter for exactly 180 seconds, and the highest temperature of the solution was recorded. The solution was constantly mixed to minimise the error due to slow convection. 8The previous procedure was repeated for the other two compounds, Na2CO3 and Na2SO4. 9 10## Results 11 12After three attempts at calculating the heat capacity of the calorimeter, an average value for the calibration constant, C_cal, equal to 286.0 J/K, was obtained. This was calculated using the second and third calibration trials (the first one was an outlier due to timing inaccuracy and possibly residue in the calorimeter). 13 14/\H = C_cal * /\T_avg / n 15 16where n is the number of mol of NaOH, in this case equal to the volume in litres (since it is a 1M solution). 17 18## Discussion 19 20Assumed density of all solutions is 1 g/mL (=> mass = volume) 21Assumed heat capacity of solution is the same as water (4.18 JK/g)