Exam 2 Flashcards
Chp 4 and 5
Synthesis Reaction
A + B –> AB
Decomposition Reaction
AB –> A + B
Single- Displacement Reaction
A + BC –> AC + B
Double-Displacement Reaction
AB + CD –> AD + CB
Combustion Reaction
X + O2 –> … + Heat
Electrolyte
a substance that disassociates into ions when dissolved in water and also forms solutions that conduct electricity
Strong Electrolyte
an electrolyte that completely disassociates into ions when dissolved in water
look for:
-soluble ionic compounds
-strong acids and bases
Weak Electrolyte
an electrolyte that partially disassociates into ions when dissolved in water
look for:
-wake acids and bases
nonelectrolyte
substance that does NOT disassociate into ions when dissolved in water and forms solutions that do NOT conduct electricity
Acids
a substance that produces H+ ions when dissolved in water
Bases
a substance that produces OH- ions when dissolved in water
Precipitation Reaction
a reaction in which a solid (or precipitate) forms when two aqueous solutions are mixed. The solid in a precipitate reaction is an insoluble ionic compound.
Molecular Equation
chemical equation showing the complete neutral formulas for each compound in the reaction
Complete Ionic Equation
chemical equations that list all the ions present in the reaction
Net Ionic Equation
chemical equation that shows only the species that actually change during the reaction
Acid-Base Reaction (Neutralization Reaction)
a reaction in which an acid reacts with a base to neutralize each other and produce water and an ionic compound (salt)
General Acid-Base Reaction
HA(aq) + BOH(aq) –> H2O(l) + BA(aq or s)
Oxidation-Reduction Reactions (Redox Reaction)
reactions where electrons are transferred form one substance to another
Oxidation (OIL)
the loss of electron, accompanied by the increase in oxidation state (OS)
Reduction (RIG)
the gain of electron, accompanied by the decrease in oxidation state (OS)
Oxidizing Agent
the substance that is being reduced and causes the oxidation of another substance
Reducing Agent
the substance that is being oxidized and causes the reduction of another substance
Stoichiometry
describes the numerical relationships between the amounts of reactants and produces in a balanced chemical equation
Limiting Reactant (LR)
the reactant that is completely consumed in a chemical reaction and limits the amount of desired product
Excess Reactant (ER)
any reactant that occurs in a quantity greater than what is required to completely reaction with LR
Theoretical Yield (TY)
maximum amount of desired product that can be made by the amount of LR –> ALWAYS determined through calculations
Actual Yield (AY)
the amount of desired product that is actually produced in a chemical reaction under experimental conditions
Percent Yield (PY)
(AY/TY) x 100%
Equivalence Point
the point (volume) at which the amount of acid is stoichiometrically equal to the amount of base in solution
Energy
the capacity to supply heat or do work
Heat
the energy transfer that occurs as a result of temperature difference
Work
the energy transfer that occurs as a result of unbalanced faces
Kinetic Energy (KE)
the energy associated with motion of the object
Thermal Energy
a form of KE that is associated with the random motion of atoms and molecules
Potential Energy (PE)
the energy associated with position or composition of an object
Chemical Energy
a form of PE that is associated with relative positions
Law of Conservation of Energy
energy can neither be created nor destroyed, only transferred from one form to another
System
the portion of the universe that is under investigation
Surroundings
everything that exists outside the system
First Law of Thermodynamics
the total energy of the universe (ie. internal energy) is constant
Internal Energy (U)
the sum of all KE and PE of every component of the system
State Function
a function whose values depend only on the state of the system, not on how the system arrived at the state
examples:
-internal energy
-enthalpy
-volume
-temperature
-pressure
-altitude
Thermal Equilibrium
the point at which there is no additional net transfer of heat between a system and its surroundings
(the amount of heat lost by one substance must be equal to the amount of heat gained by the other)
Pressure-Volume Work
the work that occurs when a volume change takes place against external pressure
Exothermic Process
a process that absorbs heat from its surrounding
Hess’s Law
if a chemical equation can be expressed as the sum of a series of steps, the delta H(rxn) for the overall reaction is equal to the sum of delta H(rxn) for the individual steps
Endothermic Process
a process that releases heat into the surrounding
Gas at Standard State
pure gas at pressure of 1 atm
Solid or Liquid at Standard State
pure substance in its most stable form at 1 pressure of 1 atm and temperature of interest (usually) 25 degrees celsius
Solution at Standard State
solution at concentration of 1M
