The lecture began with a discussion of the conservation of energy, the

change of energy is equal to the heat(q) and work(w). We then talked about

entthalpy which is defined as the heat absorbed or evolved at constant

pressure, which is usually the condition in the lab. Endothermic reactions

were defined as heat going from the surrounding to the system and exothermic

reactions consist of heat going from the system to the surrounding. We also

defined the state functions as, E, H, P, and V and non state functions as, q

and w. The lecture was concluded by using Hess's Law. According to this law,

when reactants are converted to products, the change in enthalpy is the same

whether the reaction takes place in one step or a series of steps, in other

word enthalpy change depends only on the initial and final state.