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ΔH_R1= -1.875 kJ

ΔH_R2= -4.678 kJ

ΔH_R3= -2.865 kJ

mol_R1=2.00/(22.99+16.00+1.008)= 0.05 mol

mol_R2=2.00/(22.99+16.00+1.008)= 0.05 mol

mol_R3=1.0*50.1000= 0.05 mol

ΔH/mol_R1=-1.875/0.05= -37.5 kJ/mol

ΔH/mol_R2=-4.678/0.05= -93.6 kJ/mol

ΔH/mol_R3=-2.865/0.05= -57.3 kJ/mol

-ΔH_R1  ΔH_R2  ΔH_R3

-37.5+-57.3= -94.8 kJ/mol

37.5+-93.6= -56.1 kJ/mol

|-94.8+93.6| / |-93.6| *100= 1.28% error

Conclusion:

The purpose of the lab was to practice applying Hess's Law and verifying that the heat of a reaction is equal to the sum of the other reactions. We achieved this by using a coffee cup calorimeter to combine NaOH with water and HCl and using a thermal probe to measure the initial and final temperature, which was used along with the mass or volume of NaOH, to find the heat released, which was used to find ΔH. We then used the mass of NaOH to find the ΔH/mol. We then added two reactions and compared them against the third to verify the data/calculations.