Question

QUESTION 4 Before determining the ?soltnH of the salts in part B of Experiment 4 it's necessary to calibrate the calorimeter to effective heat capacity of the calorimeter. In order to do this, the neutralisation of hydrochloric acid and sodium hydroxide is used, where the ?H for the reaction is known, along with the specific heat and density of sodium chloride, the product of the reaction. By following the example on page 4-4 of the manual and the steps laid out in the table below determine Ccalorimeter in J K-1. The information that you need is shown in the table below. Value Enthalpy change for one mole ( \Delta H ?H) -58.3 kJ mol-1

Density 1 M NaCl (?) 1.037 g mL-1

Specific heat of 1 M NaCl solution ( C C) 3.90 g-1 K-1

Molarity of sodium hydroxide(aq) and hydrochloric acid(aq) used ( c c) 2 mol L-1

Volume of each of sodium hydroxide(aq) and hydrochloric acid(aq) used ( V V) 50 mL

Average neutralisation temperature rise ( \Delta T ?T) 11.2 °C

Calculation

Moles of H2O produced n (mol) = c (mol L ?1 ) ×V (L)

Enthalpy change for the reaction ? r H (kJ) =n (mol) ×?H (kJ mol ?1 )

Enthalpy change for the corresponding temperature change ? t H (kJ) =?? r H (kJ)

Mass of solution m (g) =V (mL) ×? (g mL ?1 )

Heat capacity of the solution C solution (J K ?1 ) =m (g) ×C (J g ?1 K ?1 )

The heat capacity of the calorimeter ( C calorimeter)

Answer 1