Question

13. Given the data N,(g) + 0.9-2N0(g) 2N0(g) + O2(g) → 2NO2(g) 2N20(g)-> 2 N2(g) + O2(g) M,-+190.4 kJ/mol AH-=-129.3 kJ/mol A, =-58.7 kJ/mol For the "mol" of the units above, it means that the reaction coefficients are counted iin numbers of moles. Use Hess's law to calculate AH in kJ/mol for the reaction N20(g) + N2 (g) + 20, → 3N0(g) + NO2(g) 14. Compare the following two unbalanced violent chemical reactions that could be used in rocket engines: i) №Ha(g) + H2O2() → Ndg) + H2O(g) ii) NH3(g) + H2O2(1) → N2(g) + H2O(g) (a) Balance the reactions (b) Calculate the enthalpy changes of the two reactions (c) Which provides the most heat energy release per unit mass of the fuel (N2H4 or NH3)? (d) Which fuel would you use for a rocket engine?

Answer 1

13) Target eqn: N2O(g) N2g)202 (g)> 3NO (g)+ NO2 (g) AH? ) N2(g) +02 (g)>2NO multiply with 2 H 190.4 k 2N2 (g) +20 (8) 4NO(8) 2) 2NO(g) +02 (g)-> 2NO2 (g); multiply the 2nd equation with AH2(1904 kJ)+380.4 kJ AH2-129.3 kJ NO() 02(8)NO2 (8) AH2 129.3 kJ)-64.65 kJ 3 2N20(g)2N2 (g)+ 02(g); AH3 --158.7 kJ multiply the 2nd equation with - AH3 -158.7 kT)--79.35 kJ add the 3 equati on to get the target equation 2N,(E) +20,(8)4) NO(g)AH+380.4 kJ AH2 -64.65 kJ AH,--79.35 kJ NO(g) +- gNO2 (g) N20(g)> N2(g)+02 (g)