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11 Dec 2019

2. Given the following data:
H2O(l) → H2(g) + 1/2O2(g) ΔH° = 285.8 kJ
2HNO3(l) → N2O5(g) + H2O(l) ΔH° = 76.6 kJ
2N2(g) + 5O2(g) → 2N2O5(g) ΔH° = 28.4 kJ

Calculate ΔH° for the reaction: 1/2N2(g) + 3/2O2(g) + 1/2H2(g) → HNO3(l)
Note that you should be able to answer this one without needing to use any additional information from the thermo table.

I've attempted this question multiple times. I am able to get to the simplified eqaution broken down, but I am not able to match the answer numerically. Any concise and clear explanations would be greatly appreciated! I really need to understand the material prior to my exam!

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Related questions

DearChegg Lifesaver. Here are the requirements:

1.Use given values as stated in questions below.

2.Clearly State Answer

3.(Please) LEAVE A COMMENT if you are currently working on anyproblems.

4.Formany of these problems you will need to use tabulated thermodynamicdata. Use the Information provided after problem 17.



---------------------------------------Questions---------------------------------------------------



1.Write a balanced formation equation for HNO3 at standardconditions. For the answer, enter the sum all of the coefficientsin the balanced equation. (If thisis not an integer, enter it as a decimal, not a fraction.)


2.Calculate ?H° for the following reaction:

SiO2(s)+ 4HF(g) ? SiF4(g) + 2H2O(g)


3.Use heat of formation data to determine ?H° for the reaction:

2NH3(g)? N2(g) + 3H2(g)


4.Calculate the mass of methane that must be burned to provide enoughheat to convert 330.0 g of water at 37.0°C into steam at 124.0°C.(Assume that the H2Oproduced in the combustion reaction is steam rather than liquidwater.)


5.Acetylene burns in air according to the following equation:

C2H2(g)+ 5/2 O2(g) ? 2 CO2(g) + H2O(g)

with?H° = -1255.8 kJ.

Giventhat ?Hf° for CO2(g) = -393.5 kJ/mol and ?Hf° for H2O(g) is -241.8kJ/mol, what is ?Hf° for C2H2(g)?






6.Given the following data:

HNO3(l)? 1/2N2(g) + 3/2O2(g) + 1/2H2(g) ?H° = 174.1 kJ

2N2O5(g)? 2N2(g) + 5O2(g) ?H° = -28.4 kJ

H2O(l)? H2(g) + 1/2O2(g) ?H° = 285.8 kJ


Calculate?H° for the reaction:

2HNO3(l)? N2O5(g) + H2O(l)

Notethat you should be able to answer this one without needing to useany additional information from the thermo table.


7.Hydrocarbons containing halogens are very useful molecules insynthetic chemistry. Use tabulated thermodynamic data as needed tocalculate ?Hf° for the reactionproduct in the equation shown below if ?H° for the reaction is-177.66 kJ.

C2H4(g)+ Cl2(g) ? CH2ClCH2Cl(g)



8.Identify the following statements as true or false. (Use thedrop-down menu and select "True" or "False" for each. You must getall 6 correct.)

Allsystems become more disordered spontaneously.

Both?Ssys and ?Ssurr must equal zero at equilibrium.

Theentropy of the universe is constant; the energy of the universedecreases towards a minimum.

Allspontaneous processes release heat.

Ifa reaction is spontaneous, the reverse reaction is non-spontaneous.

Ifa process decreases the randomness of the particles of a system,the entropy of the system increases.


9.Use tabulated thermodynamic data to calculate ?S° for the reaction:

PbO2(s)+ 2Ni(s) ? Pb(s) + 2NiO(s)



10.Calculate ?S° for the combustion of ethane (C2H6) to form carbondioxide and gaseous water.



11.Urea ((NH2)2CO) can be formed from ammonia and carbon dioxide asshown in the following reaction. The ?H° value for this synthesisis -134.0 kJ. Calculatethe ?H°f for urea.

2NH3(g)+ CO2(g) ? (NH2)2CO(s) + H2O(l)


12.The ?S° value for urea the synthesis reaction above is -424.0 J/K.Calculate S° for urea.

Tries0/99


13.Calculate ?G° for the synthesis of urea under standard conditions(298 K and 1 atm).

Tries0/99


14.Compute the standard free energy change for the following reaction.

O3(g)+ NO(g) ? NO2(g) + O2(g)

Tries0/99


15.The most important commercial process for generating hydrogen gasis the water-gas shift reaction:

CH4(g)+ H2O(g) ? CO(g) + 3H2(g)

Usetabulated thermodynamic data to find ?G° for this reaction at thestandard temperature of 25°C.


16.Now calculate ?G°1100 for this process when it occurs at 1100 K.


17.The molar enthalpy of fusion (?H°) of fluorine is 0.260 kJ/mol, andthe molar entropy of fusion (?S°) of fluorine is 4.851 J/mol K.Using this information,estimate the freezing point of fluorine. (You must answer inKelvin.)

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