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R = 0.008314 kJ/K.mol; 1 Faraday (F) = 96, 500 C/mol e^-; 1 J = 1C times 1V. Hyd

ID: 1072806 • Letter: R

Question

R = 0.008314 kJ/K.mol; 1 Faraday (F) = 96, 500 C/mol e^-; 1 J = 1C times 1V. Hydrazine, H_2NNH_2, is used as a rocket fuel. Use the data below to determine if hydrazine be prepared from the following reaction under standard conditions:: N_2(g) + 2 H_2(g) rightarrow H_2NNH_2(l) Calculate Delta S_total for the following reaction, then tell whether it is spontaneous under standard conditions or not. CaCO_3(s) rightarrow CaO(s) + CO_2(g) The entropy change for a certain non-spontaneous reaction at 50 degree C is 104 J/K. Is the reaction endothermic or exothermic? Explain your answer. What is the minimum value of Delta H degree (in kJ) for the reaction? Urea, NH_2CONH_2, can be prepared by the following reaction: 2 NH_3(g)+ CO_2(g) rightarrow NH_2CONH_2 (aq) Given that Delta G degree = -13.6 kJ, calculate Delta G at 25 degree C for the following set of conditions: 10 atm NH_3, 10 atm CO_2, 1.0 M NH_2CONH_2; and 0.10 atm NH_3, 0.10 atm CO_2, 1.0 M NH_2CONH_2 Would get you more product or less product for each condition?

Explanation / Answer

1.)

N2H4(l) +  O2(g)   ------>  N2(g)   +  2H2O(l)

Molar mass of hydrazine = 32.05 g/mol

Moles of hydrazine = Mass / molar mass

                              =3.60 g / 32.05 g/mol

                              =0.1123 mol

So enthalpy change per mole of hydrazine = 69.8 kJ / 0.1123mol

                                                                ˜621 kJ

4.)

2NH3(g)+CO2(g)--->NH2CONH2(aq)+H2O(l)

we know that

dG = dGo + RT ln K

K = [NH2C0NH2] / pC02 x (pNH3)^2

K = 1 / 10 x 100

K = 1 x 10-3

dG = -13.6 x 1000 + 8.314 x 298 x ln (1 x 10-3)

dG = -13.66 kJ


B)

dG = dGo + RT ln K

K = [NH2C0NH2] / pC02 x (pNH3)^2

K = 1 / 0.1 x ( 0.1)^2

K = 1000

dG = -13.6 x 1000 + 8.314 x 298 x ln 1000

dG = 35.14 kJ

for a reaction to be spontaneous dG < 0

so

part A is spontaneous