Chemistry for Engineers: Thermochemistry Lecture Review

Potential Energy is energy stored in the ______ bonds of a substance.

An endothermic reaction is a reaction where the system absorbs energy from the surrounding in the form of ______.

Examples of an endothermic reaction include evaporation of ______.

Exothermic reaction is a reaction that releases energy from the system in the form of ______.

Examples of an exothermic reaction include burning of a ______.

Kinetic Energy is energy that comes from ______.

The first law of thermodynamics states that energy can neither be created nor destroyed but can only changed from one form to another. Heat (q) and work (w) are the only possible forms of energy transfer, this can attribute to the overall change in energy (E) of a system. So, we can write, - The change in energy is always defined as the difference between the final state and the initial state. It is a physical property of a material that measures how much heat is required to raise the temperature of one mole of that material to 1degC.

Energy is transferred into a system. Work is done on a system.

A process of measuring the amount of heat released or absorbed during a chemical reaction. It can determine whether the reaction is exothermic or endothermic.

______ is a measure of the total energy in a system/reaction. It is the total heat absorbed or released in the system. Sometimes referred to as “heat content.” The heat flow of the reaction system is equal to the difference in enthalpy between products and reactant.

A chemical equation that shows enthalpy relation between products and reactants. It must contain a balanced chemical equation, and the appropriate value and for change in enthalpy.

The sign of change in enthalpy indicates whether the reaction, when carried out at constant pressure, is endothermic (positive change in enthalpy) or exothermic (negative change in enthalpy).

The magnitude of change in enthalpy is directly proportional to the amount of reactant or product.

Change in enthalpy for a reaction is equal in magnitude but opposite in sign to change in enthalpy for the reverse reaction.

The value quoted for change in enthalpy applies when the products and reactants are at the same temperature, ordinarily taken to ______ unless specified otherwise.

Change in enthalpy is the same whether it occurs in one step or in a series of steps.