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Using the table of standard enthalpies of formation at 298 K provided in the pdf

ID: 478045 • Letter: U

Question

Using the table of standard enthalpies of formation at 298 K provided in the pdf, calculate the H° for the following reaction: NaOH(aq) + HCl(g) NaCl(aq) + H2O(l) Please give your answer in kJ. Do NOT input the units. Give your answer to ONE decimal place. For example, if your answer is 12.62581, please input 12.6. If you need to input a negative value please use the hyphen "-" followed directly by the number, NO SPACE. Do not use the underscore ("_") For example, if your answer is -15.1611, please input -15.2.

Explanation / Answer

Enthalpy of reaction = Enthalpy of products - Enthalpy of reactants.

Standard Enthalpy of formation of reactants:

NaOH(aq)= -470.1 kJ/mol

HCl(g)= -93.3 kJ/mol

Standard Enthalpy of formation of products:

NaCl(aq)= -407 kJ/mol

H2O(l)= -285.8 kJ/mol

Enthalpy of reaction at 298K=

(-407-285.8)kJ/mol - (-470.1-93.3) kJ/mol

= - 692.8 kJ/mol - (-563.4) kJ/mol = -692.8 + 563.4 kJ/mol =-129.4kJ/mol

Standard heat of reaction at 298K = -129.4 kJ/mol