 In part three of our Hesse's law experiment, we will measure the heat of neutralization of an aqueous solution of hydrochloric acid and solid sodium hydroxide. We mass out about a one gram sample of solid sodium hydroxide. In our calorimeter, we add 50 milliliters of water and 55 milliliters of the hydrochloric acid solution. We stir the solution and record an initial temperature. We then add the sodium hydroxide, stir the solution and record the maximum temperature reached.