A chemist measures the enthalpy change AH during the following reaction: 3 N2(9) + 8 H2(9)→4NH3(g) + N,H4(1) AH=-134. kJ Use this information to complete the table below. Round each of your answers to the nearest kJ/mol. reaction ΔΗ NH, () + N,H,() – N, 6) + H, 6) O kJ 4NH, (g) + N,H, (1) → 3N, (3) + 8H, (g) O kJ

Measurements show that the energy of a mixture of gaseous reactants increases by 301. kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that – 104. kJ of work is done on the mixture during the reaction. Calculate the change in enthalpy of the gas mixture during the reaction. Be sure your answer has the correct number of significant digits. O exothermic ? Is the reaction exothermic or endothermic? O endothermic

Given the standard enthalpies of formation for the following substances, determine the reaction enthalpy for the following reaction. AGran =? kJ 4A (g) + 2B (3) → 1C (g)+ 7D (g) AGi in kJ/mol Substance A (g) B (g) C(g) D (g) 76.34 + 5.24 - 55.86 - 14.55 O - 452.59 kJ/mol O + 452.59 kJ/mol O + 137.17 kJ/mol O - 141.51 kJ/mol O - 137.17 kJ/mol

One day while camping, a student used a propane stove to boil some water. The student heated 5.00 L of water from 15.6°C to 98.5°C. The molar enthalpy of combustion of propane is -2043.9 kJ/mol and heating the water required 1.38 mol of propane. Determine the efficiency of the propane camp stove if the heat released from the stove was used to heat the water. 62.4 % 38.4% D162 % 61.6%