General Chemistry Flashcards
(143 cards)
1
Q
Concentration of a solution calculated by gram equivalent weight of solute per liter of solution, often denoted by N.
A
Normality
2
Q
A solution of unknown concentration to which small volumes of a solution of known concentration are added to reach the equivalence point.
A
Titrand
3
Q
The measure of how quickly reactants are consumed and products are formed, commonly expressed in terms of mol L^‐1 s^‐1.
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Reaction Rate
4
Q
An equation used to determine a cell’s electromotive force (emf) when conditions are not standard. E{cell} = E°{cell} - (0.0592/n)logQ where E{cell} is the emf, E°{cell} is the emf under standard conditions, n is the number of electrons transferred in the oxidation-reduction reaction, and Q is the reaction quotient.
A
Nernst Equation
5
Q
The resulting positive nuclear charge an outer electron senses after accounting for the shielding effect of inner core electrons. Abbreviated Z{eff}. Increases from left to right and from bottom to top on the Periodic Table.
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Effective Nuclear Charge
6
Q
The amount of energy required to remove an electron from orbit about a gaseous atom into free space. Increases from left to right and from bottom to top on the Periodic Table.
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Ionization Energy
7
Q
A hypothetical equation showing only the species that is oxidized or reduced in a oxidation-reduction reaction and the correct number of electrons transferred between the species in the complete, balanced equation.
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Oxidation-Reduction Half-Reaction
8
Q
A reaction that will proceed or occur on its own without additional energy input from its surroundings.
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Spontaneous Reaction
9
Q
A unification of Boyle’s Law, Charles’s Law, Gay-Lussac’s law, and Avogadro’s principle into the formula that describes the behavior of ideal gases: PV = nRT.
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Ideal Gas Law
10
Q
The electrode where oxidation occurs during a cell’s oxidation-reduction reaction. Electrons always flow from the anode in an electrochemical cell.
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Anode
11
Q
A transfer of energy from a substance with a higher temperature to a substance with a lower temperature.
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Heat
12
Q
The product of the molar concentrations of dissociated ions in solution at any point in a dissociation reaction, where each ion is raised to the power of its stoichiometric coefficient. Denoted IP.
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Ion Product
13
Q
An apparatus commonly referred to as a bomb calorimeter; used to measure the amount of heat absorbed or released during a reaction.
A
Constant-Volume Calorimeter
14
Q
An equation commonly used in titration-based problems that relates the pH or pOH of a solution to the pKₐ and the ratio of the dissociated species. pH = pKₐ + log([A^-]/[HA]).
A
Henderson-Hasselbalch Equation
15
Q
The sum of all the masses present (in amu) in one molecule of a molecular compound.
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Molar Mass
16
Q
The reactant in a chemical equation that, given nonstoichiometric amounts, determines the amount of product that can form; the reactant that runs out first.
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Limited Reagent
17
Q
A reactant in which an acid and a base are combined to form a salt (and often water as well).
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Neutralization Reaction
18
Q
The point in a titration at which an equimolar amount of titrant has been added to the unknown solution.
A
Equivalence Point
19
Q
The energy released when an atom or ion in the gaseous state gains an electron. Increases from left to right and from bottom to top on the Periodic Table.
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Electron Affinity
20
Q
The ratio of the amount of solute to the amount of solution; quantified by mole fraction, molarity, molality, or normality, among other measures.
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Concentration
21
Q
States that the partial pressure of a gas dissolved in a solution is directly proportional to the partial pressure of this gas above the solution.
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Henry’s Law
22
Q
The sum of the exponents in a rate law, where each exponent provides the reaction order with respect to its reactant.
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Reaction Order
23
Q
A process in which temperature (and, therefore, internal energy) remain constant.
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Isothermal Process
24
Q
Common definition of acids as proton (H^+) donors and bases as proton acceptors.
A
Brønsted-Lowry Definition
25
A reaction in which two or more reactants combine to form a product (such as A + B ➝ C).
Combination Reaction
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A medium, commonly a liquid, into which a solute is dissolved to create a solution.
Solvent
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The energy barrier that must be overcome for a reaction to proceed; often denoted by Ea.
Activation Energy
28
A system that allows for the exchange of energy and matter across its boundaries.
Open System
29
A pressure-temperature plot showing the conditions under which a substance exists in pure phase or in equilibrium between different phases.
Phase Diagram
30
A solution containing water as its solvent.
Aqueous Solution
31
An analytical procedure in which a solution of known concentration is slowly added to a solution of unknown concentration to the point of molar equivalency, thereby providing the concentration of the unknown solution.
Titration
32
The charge assigned to an atom in a molecule or polyatomic ion, assuming even division of the electrons in a bond. Molecules containing atoms with lower formal charges tend to be more stable than those with higher formal charges.
Formal Charge
33
A system that can exchange neither energy nor matter with its surroundings.
Isolated System
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An electrochemical cell that uses an external electric source to drive a nonspontaneous (unfavorable) oxidation-reduction reaction.
Electrolytic Cell
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The highly reactive elements found in Group IA (Group 1) of the Periodic Table, except hydrogen.
Alkali Metals
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The electrons occupying the outermost electron shell of an atom that participate in chemical bonds. Atoms with the same number of valence electrons usually have similar properties.
Valence Electrons
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A chemical reaction in which an atom or ion of one compound is replaced by another atom or ion (such as A + BC ➝ B + AC).
Single-Displacement Reaction
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States that the enthalpy change of an overall reaction is equal to the sum of the standard heats of formation of the products minus the sum of the standard heats of formation of the reactants.
Hess's Law
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Law stating that energy cannot be created or destroyed but only transferred and transformed.
Law of Conservation of Energy
40
An electrode immersed in an electrolytic solution that is the site of either oxidation or reduction in an electrochemical cell.
Half-Cell
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Elements that have characteristically high electronegativity, ionization energy, and electron affinity. These elements tend to be found on the right side of the Periodic Table and are poor conductors of electricity.
Nonmetals
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A single particle or polyatomic species with an electric charge.
Ion
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The region in a molecule where atomic orbitals overlap, resulting in either a stable low-energy bonding orbital or an unstable high-energy antibonding orbital.
Molecular Orbital
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The point in a titration at which exactly half the molar equivalence of reactant is consumed by the titrant being added. At this point in an acid-base titration, the pH is equal to the pKₐ of the titrand.
Half-Equivalence Point
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The distance measured either between the nucleus and outermost electron of an atom or by the separation of the two nuclei in a diatomic element. Decreases from left to right and from bottom to top on the Periodic Table.
Atomic Radius
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Elements found in Group IIA (Group 2) of the Periodic Table.
Alkaline Earth Metals
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A system that allows for the exchange of energy, but not matter, across its boundaries.
Closed System
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The acronym for valence shell electron pair repulsion theory, which states that the three-dimensional molecular geometry about some central atom is determined by the electronic repulsion between its bonding and nonbonding electron pairs.
VSEPR Theory
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A reaction in which a species loses electrons.
Oxidation
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A point on a phase diagram at which a substance exists in equilibrium between all three phases.
Triple Point
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Inert elements naturally existing in a gaseous state that comprise Group VIII (Group 18) of the Periodic Table.
Noble Gas
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A solution of known concentration added in small volumes to a solution of unknown concentration to reach the equivalence point.
Titrant
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The pressure contribution of a single gas in a container holding a mixture of gases, as given by the equation P{A} = X{A}P{total}, where X{A} is the mole fraction of gas A and P{total} is the total pressure of the mixture.
Partial Pressure
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273 Kelvin (0° Celsius) and 1 atmosphere (760 mmHg).
Standard Temperature and Pressure (STP)
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An acid that will completely dissociate in aqueous solution (such as HCl, HI, HNO3, and HClO4).
Strong Acid
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A representation of a displacement reaction showing only the reactive species and omitting the spectator ions.
Net Ionic Reaction
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Concentration of a solution calculated by moles of solute per kilograms of solvent, often denoted by m.
Molality
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The energy of a system available to do work.
Gibbs Free Energy
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Alternate Lewis structures of the same molecule that show the delocalization of electrons within that molecule; Lewis structures that contribute to a resonance-stabilized system. Resonance structures have the same atomic connectivity but differ in the distribution of electrons.
Resonance Structures
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States that the number of moles of a gas present is proportional to its volume, assuming constant pressure and temperature.
Avogadro's Principle
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A species that is reduced in the process of oxidizing another species.
Oxidizing Agent
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The amount of heat required to raise once gram of a substance by one degree Celsius.
Specific Heat
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A rule stating that atoms tend to react in order to form a complete octet of valence electrons. Exceptions include hydrogen (stable with two electrons), Be (four), B (six); any element in Period 3 and lower (can have more than eight electrons and be stable); and molecules with an odd number of electrons.
Octet Rule
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A reaction in which a species gains electrons.
Reduction
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The product of the molar concentrations of dissociated ions in a saturated solution, where each ion is raised to the power of its stoichiometric coefficient. Denoted Ksp.
Solubility Product Constant
66
An equilibrium expression used to measure acid strength, given by the ratio of the product of the products' molar concentrations to the product of the reactants' molar concentrations, with each term raised to the power of its stoichiometric coefficient. Denoted Kₐ.
Acid Dissociation Constant
67
A species that is oxidized in the process of reducing another species.
Reducing Agent
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Concentration of a solution calculated by moles of solute per liters of solution, often denoted by M.
Molarity
69
States that at a constant pressure, the volume of an ideal gas is directly proportional to its temperature.
Charles's Law
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The process of forming a cagelike network of solvent molecules around a solute in a solution.
Solvation
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A compound, commonly an ion, dissolved in a solvent to create a solution.
Solute
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A definition of acids as producers of excess H^+ and bases as producers of excess OH^- in aqueous solutions.
Arrhenius Definition
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The molarity of a solute such that a solution is saturated (at equilibrium).
Molar Solubility
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An expression of the autoionization of water into H^+ and OH^- at a certain temperature, given by the product of the ions' molar concentrations. Denoted by Kw, and equal to 10^-14 at 25°C. Kw = [H^+][OH^-].
Water Dissociation Constant
75
States that at a constant temperature, the volume of an ideal gas is inversely proportional to its pressure.
Boyle's Law
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The properties of solutions – such as vapor pressure lowering, freezing point depression, boiling point elevation, and osmotic pressure – that are affected only by the number of solute particles dissolved and not by their chemical identities.
Colligative Properties
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A chemical reaction in which one substance breaks down into two substances (such as A ➝ B + C).
Decomposition Reaction
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The expected amount of product yielded in a reaction according to the reactants' stoichiometry.
Theoretical Yield
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A variable that depends only on the current state of a system, and not the path taken to get there. Includes pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy.
State Function
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A reaction that proceeds with the net release of heat into the surroundings.
Exothermic
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A "play-by-play" showing the individual steps of a reaction, including the formation and destruction of any reaction intermediates that may occur.
Reaction Mechanism
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A species capable of reacting as either an acid or a base. In the Brønsted-Lowry sense, a species that can pick up or give off a proton. In the Lewis sense, a species that can donate or accept a lone pair of electrons.
Amphoteric
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The total heat content of a system at a constant pressure, commonly denoted by H.
Enthalpy
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Elements that have properties between those of metals and nonmetals; includes B, Si, Ge, As, Sb, Te, Po, and At.
Metalloids
85
The quantum mechanical concept that we cannot measure the exact momentum and position of an orbiting electron simultaneously. That is, the more accurately we measure an electron's momentum, the less we know about its exact position.
Heisenberg Uncertainty Principle
86
The elements found in the B groups of the Periodic Table. These elements contain partially filled d subshells.
Transition Elements
87
A systematic pairing of a protonated species (acid) with its deprotonated form (conjugate base) or a deprotonated species (base) with it protonated form (conjugate acid). Conjugates appear on opposite sides of a chemical equation.
Conjugate Acids and Bases
88
A particle of light energy with a value equal to hf, where h is Planck's Constant and f is the frequency of radiation.
Photon
89
An oxidation-reduction reaction in which the same species is both oxidized and reduced.
Disproportionation (Dismutation)
90
A process that occurs at a constant pressure.
Isobaric Process
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A ratio (calculated as a percentage) of the actual mass of product yielded to the theoretical yield of product mass.
Percent Yield
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States that electrons will first fill orbitals within a subshell unpaired and with parallel spins before being coupled with other electrons of opposite spins in the same orbital. This method of maximizing the number of half-filled orbitals allows for the most stable distribution of electrons within a subshell.
Hund's Rule
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A method of the tendency of a species to be reduced, commonly used in identifying the anode and cathode of an electrochemical cell.
Reduction Potential
94
The study of reaction rates and the factors that affect them.
Chemical Kinetics
95
States that the vapor pressure of a solvent is proportional to the mole fraction of the solvent in the solution; provides an explanation for the boiling point elevation seen in solutions.
Raoult's Law
96
The part of the universe under consideration that is separated by some real or imaginary boundary from its surroundings.
System
97
An ion in water that is capable of conducting electricity in that solution.
Electrolyte
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A high-energy complex in which old bonds are partially broken and new bonds are partially formed. Charges existing only in the transition state are designated as partial charges.
Transition State
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States that the molar solubility of one salt is reduced when another salt, having a common ion, is brought into the same solution.
Common Ion Effect
100
An experimentally determined mathematical expression showing the rate of a reaction as a function of the concentrations of its reactants.
Rate Law
101
A solution containing a weak acid or base coupled with its conjugate salt, acting to prevent changes to the solution's pH upon the addition of acidic or basic substances.
Buffer
102
An atom or a substance that contains unpaired electrons and is consequently attracted to a magnet.
Paramagnetic
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An atom or a substance that contains no unpaired electrons and is consequently repelled by a magnet.
Diamagnetic
104
Very strong intermolecular force where a hydrogen covalently bonded to an N, O, or F is attracted to another N, O, or F.
Hydrogen Bonding
105
An electrochemical cell powered by a spontaneous oxidation-reduction reaction that produces an electric current; also called a voltaic cell.
Galvanic Cell
106
Denoted by F, it equals 9.65 × 10⁴ C/(mol e-). Commonly used in the formula It=nF, where I is current, t is time (in seconds), and n is moles of electrons transferred.
Faraday's Constant
107
A reaction that proceeds with the net absorption of heat from the surroundings.
Endothermic Reaction
108
The electrode at which reduction occurs during a cell's oxidation-reduction reaction. Electrons always flow towards the cathode in an electrochemical cell.
Cathode
109
A chemical reaction that either is driven by or produces electricity.
Electrochemical Reaction
110
A series of assumptions used to account for the behavior of ideal gases. The theory describes gases as volumeless particles in constant, random motion that exhibit no intermolecular attractions and undergo completely elastic collisions with each other and the walls of their container.
Kinetic Molecular Theory of Gases
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A definition of acids as electron pair acceptors and bases as electron pair donors.
Lewis Definition
112
The ratio of the concentrations of the products to the concentrations of the reactants at the point of equilibrium, where each reactant and product in the expression is raised to the power of its stoichiometric coefficient. Commonly denoted by Keq.
Equilibrium Constant
113
Theory stating that the rate of a reaction is directly proportional to the number of collisions that take place between reactants per second.
Collision Theory of Chemical Kinetics
114
Passive dispersion of a gas or solute throughout a medium by means of random motion.
Diffusion
115
The ratio of the concentrations of the products to the concentrations of the reactants at any point during a reaction, where each reactant and product in the expression is raised to the power of its stoichiometric coefficient. Commonly denoted by Q. Usually compared to the equilibrium constant to determine the direction a reaction will proceed to regain equilibrium.
Reaction Quotient
116
A chemical species that changes color when undergoing dissociation. Indicators are used to signal the endpoint of a titration.
Indicator
117
Two different elements that share the same electronic configuration (such as K+ and Ar).
Isoelectronic
118
States that at a constant volume, the pressure of an ideal gas is directly proportional to its temperature.
Gay-Lussac's Law
119
A chemical reaction in which two different compounds exchange an atom or ion to form two new compounds (such as AB + CD ➝ AD + CB); also called a metathesis reaction.
Double-Displacement Reaction
120
States that when a system in equilibrium is placed under one of several stressors, it will react in order to regain equilibrium.
Le Châtelier's Principle
121
A dynamic point reached by a reversible reaction in which the rate of the forward reaction is equal to the rate of the reverse reaction. There is no net change in the concentrations of the products and reactants over time.
Equilibrium
122
Elements found in Group VIIA (Group 17) of the Periodic Table.
Halogens
123
An atom or molecule that has an unpaired electron in its outermost shell.
Free Radical
124
When a solute is dissolved in a solvent, it will dissociate until reaching an equilibrium point at which the rate of dissociation equals the rate of precipitation of the solute, regardless of any additional solute introduced into the mixture.
Solution Equilibrium
125
The product of the magnitude of either partial charge in a dipole multiplied by the distance between the charges, given by the equation p = qd where p is the dipole moment, q is the partial charge, and d is the displacement vector separating the charges.
Dipole Moment
126
A measure of an atom's ability to pull electron density toward itself when involved in a chemical bond. Increases from left to right and from bottom to top on the Periodic Table.
Electronegativity
127
A type of covalent bond between atoms with the same electronegativities, resulting in an even distribution of electron density along the bond.
Nonpolar Covalent Bond
128
A process in which no heat is transferred to or from the system by its surroundings.
Adiabatic Process
129
Elements that are characteristically electropositive, malleable, and ductile. These elements tend to be found on the left side of the Periodic Table, are lustrous, and have relatively low ionization energies and electron affinities.
Metals
130
A ratio that measures how much solute can dissolve in a solvent at a given temperature.
Solubility
131
The percentages of the elements making up a compound (usually by mass in amu).
Percent Composition
132
Chemical formula showing the smallest whole-number ratio of atoms in a compound.
Empirical Formula
133
The slowest step in a reaction mechanism; determines the overall rate of the reaction.
Rate-Determining Step
134
The movement of gas from one compartment to another through a small opening under pressure.
Effusion
135
A variable that depends on the path taken to get from one state to another. Includes work and heat.
Process Function
136
A hypothetical gas containing particles with zero volume and with no attractive intermolecular forces.
Ideal Gas
137
A type of covalent bond between atoms with different electronegativities that results in an unequal sharing of electron pairs, giving the bond partially positive and partially negative poles.
Polar Covalent Bond
138
States that no two electrons in an atom can have the same set of four quantum number values.
Pauli Exclusion Principle
139
A process that will proceed bidirectionally to form both product and reactant.
Reversible Reaction
140
The chaos or randomness of a system, often denoted by S. ΔS represents the change in entropy following a reaction.
Entropy
141
Scaled value used to measure the acidic strength of a solution, calculated by taking the negative logarithm of the proton concentration in a solution: pH = -log[H^+].
pH
142
A process in which volume remains constant and no net pressure-volume work is done.
Isovolumetric (Isochoric) Process
143
Law stating that the rates at which two different gases effuse or diffuse are inversely proportional to the square root of their molar masses: r{1}/r{2} = √M{1}M{2}.
Graham's Law
