Chapter 6

• First law of thermodynamics states that energy can neither be created nor destroyed; it can only be converted from one form to another. Energy of the universe is constant.
• State function is one that depends only on the system’s present state. It is independent of the pathway. Enthalpy change is state function.
• Calorimetry is the science of measuring heats of reactions.
• Q = mc∆T
• Hess’s Law states that in going from a particular set of reactants to a particular set of the products, the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps.
• Standard enthalpy of formation is the enthalpy change when 1 mole of a substance is formed from its elements, all substances in their standard states.
• The heat capacity of a sample is defined as the amount of energy required to raise the temperature of the sample by 1 degree Celsius.