unlv.instructure.com Question 3 Using Hess' law, determine AH for the following reaction: CS2(1) + 3 Cl2(g) -> CCI4(1) + S2CI2(1) Heats of Reaction: CS2(1) + 3 O2(g) --> CO2(g) + 2 SO2(g) AHº/kJ = -1077.0 2 S(s) + Cl2(g) --> S½CI2(1) AH/kJ = -60.2 C(s) + 2 Cl2(g) --> CCI4(1) AH/kJ = -135.4 S(s) +O2(g) --> SO2(g) AH/kJ = -296.9 C(s) +O2(g) --> CO2(g) AH/kJ = -393.5 -285.3 O-297.5 -272.5 -261.3 Question 4 MacBook Pro

Calorimetry: Question #3 Octane, C3H18 , is a constituent of gasoline, and burns in the presence of oxygen to produce water and carbon dioxide: 2 C3H18 (1) + 25 O2(g) → 16 CO2(9) + 18 H2O1) ΔΗ kJ/2mol %3D rxn C3H18 (1) When a 1.00-gram sample of octane is burned in a bomb calorimeter the temperature of the water and the calorimeter rises from 25.00°C to 33.20°C. If the heat capacity, Cbomb cal, of the empty bomb calorimeter is 837 J/°C, and the mass of the water is 1.200 kg: a) Calculate the heat, q, transferred, during the combustion, to the calorimeter: 6.86 kJ (calorimter) + qbomb cal = Cbomb cal • AT b) Calculate the heat, q, transferred, during the combustion, to the water: 41.2 kJ (1.200 kg H20) + 9H20 = + mH20 • AT • SH2O c) Calculate the enthalpy change (AHº rxn = kJ/2mol) for this reaction (2 mol of C3H18 (1): [ Select ] kJ/2 mol C3H18 (1)

Using Hess's law, what is AHf rxn for the following reaction? NO(G) + O(g) – NO2(9) NO(g) + O3(9) – NO2(9) +O2(9) AH xn = -198.8 kJ/mol Og(9) – 3/2 02(9) AHrxn = -142.2 kJ/mol 02(9) → 20(9) AH Prxn = +498.8 kJ/mol -839.8 kJ/mol -306.0 kJ/mol 394.9 kJ/mol 157.9 kJ/mol O 442.3 kJ/mol QUESTION 8 Octane (C3H18) undergoes combustion according to the following thermochemical equation. 2C8H18() + 2502(g) – 16CO2(g) + 18H20() AH°rxn = -1.0940 x 104KJ/mol What is the standard enthalpy of formation of liquid octane? AH°{(CO2(g)) = -393.5 kJ/mol and AH°F{H2O(1)) = -285.8 kJ/mol 495 kl/mol O -250 kJ/mol -495 kJ/mol -10,940. kJ/mol -2188 kJ/mol

N2(g) + O2(g)< -----> 2 NO(g)   H = +180.7 kJ 2 H2O(l) <-----> 2 H2(g) + O2(g)   H = +571.7 kJ 4 NH3(g) + 5 O2(g) <-----> 4 NO(g) + 6 H2O(l)   H = -1167.1 kJ Use Hess's law to calculate H for the reaction below. 2 NH3(g)  <----->  N2(g) + 3 H2(g)