(show all your works from part a to part h and please don\'t skip any questions

Question

(show all your works from part a to part h and please don't skip any questions. Thanks you)

c. what convention is used for heats of formation and free energies of formation of the elements in their standard states

d. what are allotropes? why are they important when determining standard states and list an example?

f. using the picture(3 pictures attached at the bottom of the questions part h), what is the standard enthalpy of formation of ethanol

g. write the balanced equation for the formation of carbon monoxide from its elements

h. the enthalpy change for the equation that you wrote in part g is - 221.0 kJ/mol. the enthalpy values have different values

Explanation / Answer

a. standard heat of formation of a compound is the total change in the enthalpy observed when the compound is formed from its elements at standard condition.

b. The superscript in the value suggests the change has occured at standard condition that is at 1 atm pressure and at 298.15 K temperature.

c. For measuring the standard free energy and enthalpy of a compound we use the standard values of its elements.

d. Allotropes are physical forms of an element. It is the different forms in which a given element may exist. Say for example, carbon may exist as graphite or diamond. Both of which have different values of standard enthalpy and free energy.

e. Equation dHof ethanol,

2C(graphite) + 3H2(g) + 1/2O2(g) ---> C2H5OH(l)

f. Using standard enthalpy of combustion for ethanol dHocomb = -1368 kJ/mol

and standard enthalpy of formation for CO2 and H2O and O2

-1368 = (2 x -393.5 + 3 x -285.8) - (dHof(ethanol) + 3 x 0)

dHof = -276.4 kJ/mol

g. Equation,

C(s) + 1/2O2(g) ---> CO(g)

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