chem final

Mole

Moles are the unit chemists use to count particles.

Avogadro’s number

6\.02 x 1023

Empirical formula

the smallest whole-number mole ratio of the elements.

Molecular formula

the actual number of atoms of each element in one molecule or formula unit of the substance. 

Precipitate

dissolved substances react to form one (or more) solid products

Coefficient

the number written in front of a reactant or product - it is a multiplier.

Synthesis reaction

two or more substances (elements and/or compounds) react to produce a single product. 

A+B=AB

Single replacement reaction

the atoms of one element replace the atoms of another element in a compound.

A+BX=AX+B

Double replacement reaction

ions exchange between two compounds. 

AX+BY=AY+BX

Stoichiometry

the study of quantitative relationships between the amounts of reactants used and the amounts of products formed by a chemical reaction. 

Limiting reactant

limits the extent of the reaction and thereby determines the amount of product formed.

Kinetic molecular theory

explains how particles move and behave at the molecule level.  

Solute vs. solvent

The dissolving medium is called the solvent. A substance that dissolves in the medium is called a solute.

What increases solubility in solutions

Stirring or shaking increases the rate of solvation, breaking the solute into small pieces increases surface area and allows more collisions to occur, as temperature increases, rate of solvation increases.

Endothermic vs. exothermic

Endothermic and exothermic are two types of chemical reactions. In an endothermic reaction, energy is absorbed from the surroundings, resulting in a decrease in temperature. In an exothermic reaction, energy is released into the surroundings, resulting in an increase in temperature.

Catalyst

something that speeds up the rate of the reaction

Reversible reaction

a chemical reaction that can occur in both the forward and reverse directions

How equilibrium shifts when changing \[ \]

when products are added: shift left, when products are removed: shift right, when reactants are added: shift right, when reactants are removed: shift left

How equilibrium shifts when changing pressure/volume

when pressure increases/volume decrease: shift toward side with fewer moles

when pressure decreases/volume increases: shift toward side with more moles

How equilibrium shifts when changing temperature

exothermic: if temp increases shift left, if temp decreases shift right

endothermic: if temp increases shift right, if temp decreases shift left

K is greater than 1

Products are favored at equilibrium (there are more products than reactants)

K is less than 1

Reactants are favored at equilibrium (there are more reactants than products)

Enthalpy

the total heat content at constant pressure

Entropy

the randomness of all things in the universe.

Nuclear decay

unstable nuclei release energy by emitting radiation. 

Fission vs. fusion

fission: splitting of a nucleus into fragments

fusion: combining of atomic nuclei

Alpha decay particle

4/2 He

Gamma ray charge

does not change

Beta decay particle

0/-1

Least penetrating radiation

alpha particles

Transmutation reaction

the conversion of an element into another element.