Question

Please solve questions 1, 2 and 3

At what temperatures is the reaction below spontaneous? 2 H2(g) + O2(g) + 2 H2O(l) Select one: O a. at T > ~1750 K O b. at T < ~1750 K O c. at T > ~1.75 K. d. at T < ~ 1.75 K O e. The reaction is spontaneous at all temperatures. Which one of the following thermodynamic quantities is not a state function? Select one: O a. entropy b. Gibbs free energy O c. enthalpy d. work o e. internal energy Calculate the enthalpy of formation of hydrazine, N2H4, given 3 N2H4(8) ► 4 NH3 (8) + N2(8) AH = -471.4 kJ/mol Select one: o a. -89.21 kJ/mol O b. -95.55 kJ/mol c. 95.55 kJ/mol O d. 46.19 kJ/mol O e. 89.21 kJ/mol 0

Answer 1

2H2(g) + O2(g) ------------> 2H2O(l)

$\Delta$H0 = 2*-285.83-(2*0 + 0)

        = -571.66KJ/mole

        = -571660J/mole

$\Delta$S0 = 2*69.91-(2*130.684 + 205)

        = -326.548J/mol-K

$\Delta$G0   <0 for spontaneous reaction

$\Delta$H0 - T$\Delta$S0 <0

$\Delta$H0 <T$\Delta$S0

$\Delta$H0/$\Delta$S0 <T

-571660/-326.548<T

1750<T

a. at T>1750K >>>>answer

work and heat are path functions

entropy, enthalpy, Gibb's free energy,internal energy are state functions

d.work >>>>answer

3N2H4(g) -----------> 4NH3(g) + N2(g)     $\Delta$ H = -471.4KJ/mole

$\Delta$H   = $\Delta$ H products - $\Delta$ H reactants

-471.4 = 4$\Delta$H(NH3(g)) + $\Delta$ H (N2(g)) - 3 $\Delta$ H (N2H4(g) )

-471.4 = 4*-46.11 + 0 -3 $\Delta$ H (N2H4(g) )

$\Delta$H (N2H4(g) ) = 95.55KJ/mole

c. 95.55KJ/mole >>>>answer