In: Chemistry
A student gets the following data for the heat of neutralization trials using 1.0 M NaOH and 1.0 M HCl.
A. Mass of calorimeter /g trial1:43.5
B. Mass HCl and calorimeter / g trial1:64.0
C. Mass calorimeter, HCl and NaOH / g trial1:85.0
D1. Mass HCl / g (B - A) trial1:.......
D2. Mass NaOH /g (C - B) trial1:.......
Mass of Solution (D1 + D2) trial1:.......
Initial temp. HCl measured / C (therm 1) trial1:22.1
Initial temp. HCl corrected / C trial1:........
Initial temp. NaOH measured / C (therm 2) trial1:21.6
Initial temp. NaOH corrected / C trial1:.......
E. Average Initial Temp corrected / C trial1:.......
Final temp. measured / C (therm 1) trial1:28.8
F. Final temp. corrected / C trial1:.......
G. Temp. change corrected / C o (F - E) trial1:........
Using this data, determine the Molar Enthalpy of Neutralization for this trial. The mcalib calib is 0.969 and b is 2.0 C for both Thermometer 1 and Thermometer 2 and B the calculated heat capacity of the calorimeter was 33 J °C-1 .
A. Mass of calorimeter /g trial1: 43.5
B. Mass HCl and calorimeter / g trial1: 64.0
C. Mass calorimeter, HCl and NaOH / g trial1: 85.0
D1. Mass HCl / g (B - A) trial1: 29.0
D2. Mass NaOH /g (C - B) trial1: 21.0
Mass of Solution (D1 + D2) trial1: 50.0
Initial temp. HCl measured / C (therm 1) trial1: 22.1
Initial temp. HCl corrected / C trial1: 22.1 + 0.969 = 23.069
Initial temp. NaOH measured / C (therm 2) trial1: 21.6
Initial temp. NaOH corrected / C trial1: 21.6 + 2 = 23.6
E. Average Initial Temp corrected / C trial1: 23.3345
Final temp. measured / C (therm 1) trial1: 28.8
F. Final temp. corrected / C trial1: 28.8 + 0.969 = 29.769
G. Temp. change corrected / C o (F - E) trial1: 29.769 - 23.3345 = 6.4345
Heat of neutralization : (msol * Cpwater * deltaT) + (Cpcal * deltaT)
H = (50g * 4.18 J/gºC * 6.4345) + (33 J/ºC * 6.4345) = 1557.15 J/mol = 1.56 kJ
We have 21g of NaOH, which are aproximately, taking density of 1 kg/L and 1 M, 0.021 moles
We have 29 g of HCl, which are 0.029 moles
We divide the heat by 0.021 moles to get molar heat of neutralization:
1.56 kJ / 0.021 moles = 74.2857 kJ/mol