Part A Determine the enthalpy for this reaction: Ca(OH)2(s)+CO2(g)CaCO3(s)+H2O(l
ID: 909264 • Letter: P
Question
Part A
Determine the enthalpy for this reaction:
Ca(OH)2(s)+CO2(g)CaCO3(s)+H2O(l)
Express your answer in kilojoules per mole to one decimal place.
Part B
Consider the reaction
Ca(OH)2(s)CaO(s)+H2O(l)
with enthalpy of reaction
Hrxn=65.2kJ/mol
What is the enthalpy of formation of CaO(s)?
Express your answer in kilojoules per mole to one decimal place.
± Enthalpy
Enthalpy H is a measure of the energy content of a system at constant pressure. Chemical reactions involve changes in enthalpy, H, which can be measured and calculated:
Hrxn=productsmHfreactantsnHf
where the subscript "rxn" is for "enthalpy of reaction" and "f" is for "enthalpy of formation" and m and nrepresent the appropriate stoichiometric coefficients for each substance.
The following table lists some enthalpy of formation values for selected substances.
Hrxn= kJ/molExplanation / Answer
Ca(OH)2(s)+CO2(g)CaCO3(s)+H2O(l)
Check if bbalanced:
it is balanced
H = Hprod - Hreact = (1207.0 + 285.8)-(986.1+-393.5) = -113.2 kJ/mol
B)
when
Ca(OH)2(s)CaO(s)+H2O(l) Hrxn=65.2kJ/mol
then
Hrxn = Hprod - Hreact
65.2 = HCaO + HH2O - HCa(OH)2
65.2 = HCaO + 285.8 - 986.1 = 700.3
65.2 = HCaO + 700.3
HCaO = 65.2-700 = -634.8