Energy transfer, calorimetry, enthalpy and Hess's law

Learning objectives

Classify a process as endothermic or exothermic from the sign of q or ΔH, and explain the direction of energy transfer between system and surroundings at the particulate level

Calculate heat transferred using q = mcΔT, analyze calorimetry data to determine an enthalpy change per mole, and explain why an insulated calorimeter is assumed to lose no heat

Explain enthalpy changes of phase transitions in terms of intermolecular forces, and calculate the energy needed for a process that includes both heating and a change of state

Estimate the enthalpy change of a gas-phase reaction from average bond enthalpies, explaining why bond breaking is endothermic and bond forming exothermic

Apply Hess's law and standard enthalpies of formation to calculate the enthalpy change of a reaction, and manipulate given thermochemical equations correctly by reversing and scaling them

Evaluate an experimental enthalpy value against an accepted value and identify whether a stated procedural error would make the magnitude too large or too small