Chem 1A Unit 2

Spontaneous process

Natural tendency to occur under certain conditions

Nonspontaneous process

Will not take place unless it’s “driven” by the continual input of energy by an external source

Radioactive decay

A spontaneous process in which the nuclei of unstable isotopes emit radiation as they are converted to more stable nuclei

Graphitization

Conversion from the diamond allotrope to graphite allotrope

A spontaneous process takes place when it results in a ____ _____ distribution of matter or energy

Microstate (W)

Specific configuration of the locations and energies of the atoms or molecules that comprise a system

As microstates increase, ____ increases

Entropy

Distributions

Microstates with equivalent particle arrangements that are grouped together

What factors increase entropy?

Increased temperature, kinetic energy, and atom weight, a mixture of particles, and as particles are less bound together (gases have more entropy than solids, ie.)

Physical change

Change in the state or properties of matter without any accompanying change in chemical composition

Chemical change

Always produces one or more types of matter that differ from the matter present before the change

Extensive property

Depends on the amount of matter present; mass and volume

Intensive properties

Don’t depend on the amount of matter present; temperature

Chemical equation

Represents the identities and relative quantities of substances undergoing a chemical or physical change

Reactants

Substances undergoing chemical reaction; formulas on the left side of the equation

Products

Substances generated by the reaction; formulas on right side of the equation

Coefficient

Relative number of reactant and product species in a chemical reaction

Balanced equation

Has the same number of atoms for each element involved in the reaction on the reactant and product side of the equation

How do you calculate the number of atoms in a balanced equation?

By multiplying the coefficient of any formula containing that element by the element’s subscript in the formula

molecular equations 

don’t explicitly represent the ionic species that are present in solution; ionic compounds dissolved in water are more realistically represented as dissociated ions  

complete ionic equations

explicitly represent all dissolved ions; replaced by formulas for their dissociated ions

spectator ions

present in identical forms on both sides of the equation; presence is required to maintain charge neutrality

net ionic equation 

formed when you remove spectator ions from the ionic equation