I need help fixing the rest of the table Data and Results Use the table below to

Question

I need help fixing the rest of the table

Data and Results Use the table below to record your data and results. As a general rule, mass and moles should be expressed to two decimal places. All others should have one decimal place Trial 1 50 50 22.0 82.0 52.0 54.0 +5852 6688 836 33.5 14.94 28.9 Trial 2 50 50 Mass of hot water,g Mass of cold water, g Initial temperature of cold water, Tc Initial temperature of hot water, Th Average temperature, Ta (Tc+Th)/2 22.0 83.0 52.5 55.0 5852 6897 1045 rature at time 0 from graph To Heat lost by the hot water Heat gained by the cold water Heat gained by calorimeter in J Temperature change of the cold water in the calo Heat capacity (C) of the calorimeter in J/oc X33.6 14.95 rage heat capacity (C) of calorimeter in J/oc)

Explanation / Answer

First table:

Temperature change of the cold water in the calorimeter Trial 1: 52-22 = 30          Trial 2: 52.5- 22.0 = 30.5

Heat capacity of the calorimeter in J/oC =     Trial 1: 836/30 = 27.86   Trial 2:    1045/30.5 = 34.60

Average heat capacity of the calorimeter :     31.2

Second table:

Change in temperature (oC) dT:   5,   22,   28, -3,     -2,      0

Heat absorbed by the solution: (mass of water and slat is included)

Heat absorbed = heat capacity of water*mass of solution*temperature change

For first column = 4.186 J/g/oC*105g*5 oC = 2197.6 J

So starting from 1st column:   2197.6,     10130.1, 19339.3, -1318.5,   -920.9,    0.0

Heat capacity of the calorimeter, from table 1:    31.2,    31.2,    31.2,    31.2,    31.2,     31.2 (it is same for all)

Heat absorbed by calorimeter (J) (Heat capacity times dT):   means heat capacity times change in temperature:   if we calculate for first column = 31.2 * 5 = 156 J

So from first column = 156, 686,   873,    -93,   -62, 0

Change in enthalpy of a solution can be measured (but absolute measurement is difficult)

Enthalpy is the energy measurement of solution at constant pressure. If we assume that for solutions pressure is constant then the enthalpy of the solution will be same as absorbed heat by the solution.

Then unit conversion for enthalpy is easy   If enthalpy is b J and want to convert it into KJ then multiply the quantity with 0.001.

Enthalpy in KJ/mol can be calculated by dividing obtained values in second last row of the table second by the total mols of solution (means    moles of water+moles of salt)…….. 100 g water contains =100/18 = 5.55 mol   

     

Average enthalpy/mol can be obtained by dividing 3 values of cacl2 solution from 3.

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