The normal freezing point of n-octane (C₈H₁₈) is -57 °C. (a) Is the freezing of n-octane an endothermic or exothermic process?

Without referring to tables, predict which of the following has the higher enthalpy in each case: (b) 2 mol of hydrogen atoms or 1 mol of H₂

Calculate ΔE and determine whether the process is endothermic or exothermic for the following cases: (b) A system releases 66.1 kJ of heat to its surroundings while the surroundings do 44.0 kJ of work on the system.

Consider the combustion of liquid methanol, CH₃OH(l): CH₃OH(l) + 3/2 O₂(g) → CO₂(g) + 2 H₂O(l) ΔH = -726.5 kJ (d) If the reaction were written to produce H₂O(g) instead of H₂O(l), would you expect the magnitude of ΔH to increase, decrease, or stay the same? Explain.