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53 terms

Chemistry 621A - Midterm Review Set

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Saturated Solution
the maximum amount of solute for a given quantity of solvent
solubility
the amount of solute that dissolves in a given quantity of solvent
unsaturated solution
a solution in which more solute can be dissolved
miscible
pairs of liquid that dissolve in each other in all proportions
immiscible
liquid solutes and solvents that are not soluble in each other
Supersaturated Solution
a mixture that has more dissolved solute than is predicted by its solubility at a given temperature
Henry's Law
at a given temperature the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid
Concentration
the strength of a solution
Dilute solution
a solution that contains a small amount of solute
Concentrated Solution
contains a large amount of solute
Molarity (M)
the concentration of solute in a solution expressed as the number of moles of solute dissolved in 1 liter of solution
Colligative Property
A property of a solution that depends on the number, not the identity, of the solute particles.
Freezing Point Depression
the difference in temperature between the freezing point of a solution and the freezing point of the pure solvent
Boiling Point Elevation
the difference in temperature between the boiling point of a solution and the boiling point of the pure solvent
Thermochemistry
the study of energy changes that occur during chemical reactions and changes in state
Chemical Potential Energy
energy stored in chemical bonds
Heat (q)
energy that transfers from one object to another because of a temperature difference between the objects
System
a part of the universe on which you focus your attention
Surroundings
everything else in the universe
Law of Conservation of Energy
the law that states that energy cannot be created or destroyed but can be changed from one form to another
Endothermic Process
a process that absorbs heat from the surroundings
Exothermic
chemical reaction in which energy is primarily given off in the form of heat
Specific Heat
the heat required to raise the temperature of one gram of a substance one degree centigrade
Calorimetry
the precise measurement of heat flow out of a system for chemical and physical processes
Calorimeter
an insulated device used to measure the absorption or release of heat in chemical or physical processes
Enthalpy (H)
the heat content of a system at constant pressure
Thermochemical Equation
a chemical equation that includes the enthalpy change
Heat of Reaction
the enthalpy change for a chemical equation exactly as it is written
Heat of Combustion
the heat of reaction for the complete burning of one mole of a substance
Molar Heat of Fusion (∆Hfus)
heat absorbed by one mole of substance in melting from solid-liquid at constant temperature
Molar Heat of Solidification (∆Hsolid)
heat lost when one mole of liquid solidifies at constant temperature
Molar Heat of Vaporization (∆Hvap)
the heat that must be added to 1 mole of liquid to convert it to vapor with no change in temperature
Molar Heat of Condensation (∆Hcon)
the amount of heat r4eleased when 1 mole of vapor condenses at the normal boiling point
Molar Heat of Solution (∆Hsoln)
change heat cause by dissolution of one mole substance
Hess' Law of Heat Summation
states that if you add two or more thermochemical equations to give a final equation, then you can also add the heats of reaction to give the final heat of reaction
Standard Heat of Formation (∆Hf)
is the change in enthalpy that accompanies the formation of one mole of a compound from its elements with all substances in their standard states at 25C
Rate
amount of change of one measurement in a given amount of time
Collision Theory
atoms, ions, and molecules can react to form products when they collide, provided that the particles have enough kinetic energy
Activation Energy
the minimum amount of energy required to start a chemical reaction
Activated Complex
an unstable arrangement of atoms that exists momentarily at the peak of the activation-energy barrier; an intermediate or transitional structure formed during the course of a reaction
Transition State
a term sometimes used to refer to the activated complex
Inhibitor
a substance that interferes with the action of a catalyst
Reversible Reaction
a reaction in which the conversion of reactants into products and the conversion of products into reactants occur simultaneously
Chemical Equilibrium
In a reversible chemical reaction, the point at which the rate of the forward reaction equals the rate of the reverse reaction.
Equilibrium Position
the relative concentrations of the reactants and products at equilibrium
Le Chatelier's Principle
when a stress is applied to a system in dynamic equilibrium, the system changes in a way that relieves the stress
Equilibrium Constant (Keq)
The ratio of product concentrations to reactant concentration at equilibrium, with each concentration raised to a power equal to the number of moles of that substance
Solubility Product Constant (Ksp)
an equilibrium constant that can be applied to the solubility of electrolytes; it is equal to the product of the concentration terms each raised to the power of the coefficient of the substance in the dissociation equation
Rate Law
an expression relating the rate of a reaction to the concentration of the reactants
Specific Rate Constant (K)
a proportionality constant relating the concentrations of reactants to the rate of the reaction
First Order Reaction
the reaction rate is directly proportional to the concentration of only one reactant
Elementary Reaction
a reaction in which reactants are converted to products in a single step
Reaction Mechanism
a series of elementary reactions that take place during the course of a complex reaction