GenChem 2 Other Topics for Exam 3rd Cycle

Thermochemistry

Is the study of heat changes that accompany chemical reactions and phase changes. It helps to determine whether a particular chemical reaction will occur and to know if it will release or absorb energy as it occurs. To calculate the amount of energy released or absorbed to determine if a chemical reaction is an economically viable process.

System

A specific part of the universe that contains the reaction or process you wish to study.

CHOICES (System, Surroundings, Universe)

Surroundings

Everything in the universe other than the system.

CHOICES (System, Surroundings, Universe)

Universe

System plus surroundings.

CHOICES (System, Surroundings, Universe)

Enthalpy

Is the heat content of a system at constant pressure.

Calorimetry

It measures the heat content of a chemical reaction.

Calorimeter

Is a device used to measure the amount of heat involved in a chemical or physical process. For example, when an exothermic reaction occurs in solution in a calorimeter, the heat produced by the reaction is absorbed by the solution, which increases its temperature.

Heat Capacity

Defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. The SI unit of heat capacity is joule per kelvin (J/K). It is an extensive property.

Hess’s Law

States that if you can add two or more thermochemical equations to produce a final equation for a reaction, then the sum of the enthalpy changes for the individual reactions is the enthalpy change for the final reaction.

Spontaneous Process

Any physical or chemical change that once begun; occurs with no outside intervention. For many of these processes, some energy may be required from the surroundings to get the process started, for example, using a match to light a Bunsen burner.

Entropy

It is a measure of the number of possible ways that the energy of a system can be distributed, and this is related to the freedom of the system’s particles to move and number of ways they can be arranged It is sometimes considered to be a measure of the disorder or randomness of the particles that make up a system In general, it is increased when volume, energy, number of particles or the particle’s movement of freedom increases.

Free Energy

Useful energy; energy available to do work. If the change is negative, reaction is spontaneous but if it  is positive the reaction is non spontaneous.

CHOICES (Free Energy or Gibbs Free Energy)

Gibbs Free Energy

The free energy released or absorbed in a chemical reaction is equal to the difference between the enthalpy change and the product of the change in entropy and the temperature.

CHOICES (Free Energy or Gibbs Free Energy)