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Some substances form crystalline solids consisting of particles in a very organized structure; others form amorphous (noncrystalline) solids with an internal structure that is not ordered. The main types of crystalline solids are ionic solids, metallic solids, covalent network solids, and molecular solids. The properti...
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The structures of crystalline metals and simple ionic compounds can be described in terms of packing of spheres. Metal atoms can pack in hexagonal closest-packed structures, cubic closest-packed structures, body-centered structures, and simple cubic structures. The anions in simple ionic structures commonly adopt one o...
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C g = k P g C g = k P g
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( P A = X A P A * ) ( P A = X A P A * )
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P solution = ∑ i P i = ∑ i X i P i * P solution = ∑ i P i = ∑ i X i P i *
https://openstax.org/books/chemistry-atoms-first-2e/pages/11-key-equations
P solution = X solvent P solvent * P solution = X solvent P solvent *
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Δ T b = K b m
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Δ T f = K f m
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Î = MRT
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alloy : solid mixture of a metallic element and one or more additional elements
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amphiphilic : molecules possessing both hydrophobic (nonpolar) and a hydrophilic (polar) parts
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boiling point elevation : elevation of the boiling point of a liquid by addition of a solute
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boiling point elevation constant : the proportionality constant in the equation relating boiling point elevation to solute molality; also known as the ebullioscopic constant
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colligative property : property of a solution that depends only on the concentration of a solute species
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colloid : (also, colloidal dispersion) mixture in which relatively large solid or liquid particles are dispersed uniformly throughout a gas, liquid, or solid
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crenation : process whereby biological cells become shriveled due to loss of water by osmosis
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dispersed phase : substance present as relatively large solid or liquid particles in a colloid
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dispersion medium : solid, liquid, or gas in which colloidal particles are dispersed
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dissociation : physical process accompanying the dissolution of an ionic compound in which the compound’s constituent ions are solvated and dispersed throughout the solution
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electrolyte : substance that produces ions when dissolved in water
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emulsifying agent : amphiphilic substance used to stabilize the particles of some emulsions
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emulsion : colloid formed from immiscible liquids
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freezing point depression : lowering of the freezing point of a liquid by addition of a solute
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freezing point depression constant : (also, cryoscopic constant) proportionality constant in the equation relating freezing point depression to solute molality
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gel : colloidal dispersion of a liquid in a solid
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hemolysis : rupture of red blood cells due to the accumulation of excess water by osmosis
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Henry’s law : the proportional relationship between the concentration of dissolved gas in a solution and the partial pressure of the gas in contact with the solution
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hypertonic : of greater osmotic pressure
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hypotonic : of less osmotic pressure
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ideal solution : solution that forms with no accompanying energy change
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immiscible : of negligible mutual solubility; typically refers to liquid substances
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ion pair : solvated anion/cation pair held together by moderate electrostatic attraction
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ion-dipole attraction : electrostatic attraction between an ion and a polar molecule
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isotonic : of equal osmotic pressure
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miscible : mutually soluble in all proportions; typically refers to liquid substances
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molality (m) : a concentration unit defined as the ratio of the numbers of moles of solute to the mass of the solvent in kilograms
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nonelectrolyte : substance that does not produce ions when dissolved in water
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osmosis : diffusion of solvent molecules through a semipermeable membrane
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osmotic pressure (Î) : opposing pressure required to prevent bulk transfer of solvent molecules through a semipermeable membrane
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partially miscible : of moderate mutual solubility; typically refers to liquid substances
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Raoult’s law : the relationship between a solution’s vapor pressure and the vapor pressures and concentrations of its components
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saturated : of concentration equal to solubility; containing the maximum concentration of solute possible for a given temperature and pressure
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semipermeable membrane : a membrane that selectively permits passage of certain ions or molecules
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solubility : extent to which a solute may be dissolved in water, or any solvent
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solvation : exothermic process in which intermolecular attractive forces between the solute and solvent in a solution are established
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spontaneous process : physical or chemical change that occurs without the addition of energy from an external source
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strong electrolyte : substance that dissociates or ionizes completely when dissolved in water
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supersaturated : of concentration that exceeds solubility; a nonequilibrium state
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suspension : heterogeneous mixture in which relatively large component particles are temporarily dispersed but settle out over time
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Tyndall effect : scattering of visible light by a colloidal dispersion
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unsaturated : of concentration less than solubility
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van’t Hoff factor (i) : the ratio of the number of moles of particles in a solution to the number of moles of formula units dissolved in the solution
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weak electrolyte : substance that ionizes only partially when dissolved in water
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A solution forms when two or more substances combine physically to yield a mixture that is homogeneous at the molecular level. The solvent is the most concentrated component and determines the physical state of the solution. The solutes are the other components typically present at concentrations less than that of the ...
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Substances that dissolve in water to yield ions are called electrolytes. Electrolytes may be covalent compounds that chemically react with water to produce ions (for example, acids and bases), or they may be ionic compounds that dissociate to yield their constituent cations and anions, when dissolved. Dissolution of an...
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The extent to which one substance will dissolve in another is determined by several factors, including the types and relative strengths of intermolecular attractive forces that may exist between the substances’ atoms, ions, or molecules. This tendency to dissolve is quantified as a substance’s solubility, its maxim...
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Properties of a solution that depend only on the concentration of solute particles are called colligative properties. They include changes in the vapor pressure, boiling point, and freezing point of the solvent in the solution. The magnitudes of these properties depend only on the total concentration of solute particle...
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Colloids are mixtures in which one or more substances are dispersed as relatively large solid particles or liquid droplets throughout a solid, liquid, or gaseous medium. The particles of a colloid remain dispersed and do not settle due to gravity, and they are often electrically charged. Colloids are widespread in natu...
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Δ S = q rev T Δ S = q rev T
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S = k ln W
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Δ S = k ln W f W i Δ S = k ln W f W i
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Δ S ° = ∑ ν S ° (products) − ∑ ν S ° (reactants) Δ S ° = ∑ ν S ° (products) − ∑ ν S ° (reactants)
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Δ S = q rev T Δ S = q rev T
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Δ S univ = Δ S sys + Δ S surr
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Δ S univ = Δ S sys + Δ S surr = Δ S sys + q surr T Δ S univ = Δ S sys + Δ S surr = Δ S sys + q surr T
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Δ G = Δ H − T Δ S
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entropy (S) : state function that is a measure of the matter and/or energy dispersal within a system, determined by the number of system microstates; often described as a measure of the disorder of the system
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Gibbs free energy change (G) : thermodynamic property defined in terms of system enthalpy and entropy; all spontaneous processes involve a decrease inG
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microstate : possible configuration or arrangement of matter and energy within a system
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nonspontaneous process : process that requires continual input of energy from an external source
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reversible process : process that takes place so slowly as to be capable of reversing direction in response to an infinitesimally small change in conditions; hypothetical construct that can only be approximated by real processes
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second law of thermodynamics : all spontaneous processes involve an increase in the entropy of the universe
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spontaneous change : process that takes place without a continuous input of energy from an external source
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standard entropy (S°) : entropy for one mole of a substance at 1 bar pressure; tabulated values are usually determined at 298.15 K
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standard entropy change (ΔS°) : change in entropy for a reaction calculated using the standard entropies
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standard free energy change (ΔG°) : change in free energy for a process occurring under standard conditions (1 bar pressure for gases, 1 M concentration for solutions)
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standard free energy of formation(ΔGf°)(ΔGf°) : change in free energy accompanying the formation of one mole of substance from its elements in their standard states
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third law of thermodynamics : entropy of a perfect crystal at absolute zero (0 K) is zero
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Chemical and physical processes have a natural tendency to occur in one direction under certain conditions. A spontaneous process occurs without the need for a continual input of energy from some external source, while a nonspontaneous process requires such. Systems undergoing a spontaneous process may or may not exper...
https://openstax.org/books/chemistry-atoms-first-2e/pages/12-summary
Entropy (S) is a state function that can be related to the number of microstates for a system (the number of ways the system can be arranged) and to the ratio of reversible heat to kelvin temperature. It may be interpreted as a measure of the dispersal or distribution of matter and/or energy in a system, and it is ofte...
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For a given substance, entropy depends on phase withSsolid<Sliquid<Sgas. For different substances in the same physical state at a given temperature, entropy is typically greater for heavier atoms or more complex molecules. Entropy increases when a system is heated and when solutions form. Using these guidelines, the si...
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The second law of thermodynamics states that a spontaneous process increases the entropy of the universe,Suniv> 0. If ΔSuniv< 0, the process is nonspontaneous, and if ΔSuniv= 0, the system is at equilibrium. The third law of thermodynamics establishes the zero for entropy as that of a perfect, pure crystalline solid ...
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Gibbs free energy (G) is a state function defined with regard to system quantities only and may be used to predict the spontaneity of a process. A number of approaches to the computation of free energy changes are possible.
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Q c = [ C ] x [ D ] y [ A ] m [ B ] n for the reaction m A + n B ⇌ x C + y D Q c = [ C ] x [ D ] y [ A ] m [ B ] n for the reaction m A + n B ⇌ x C + y D
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Q P = ( P C ) x ( P D ) y ( P A ) m ( P B ) n for the reaction m A + n B ⇌ x C + y D Q P = ( P C ) x ( P D ) y ( P A ) m ( P B ) n for the reaction m A + n B ⇌ x C + y D
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P = MRT
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K c = Q c at equilibrium
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K p = Q p at equilibrium
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K P = K c ( RT ) Δ n
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equilibrium : state of a reversible reaction in which the forward and reverse processes occur at equal rates
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equilibrium constant (K) : value of the reaction quotient for a system at equilibrium; may be expressed using concentrations (Kc) or partial pressures (Kp)
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heterogeneous equilibria : equilibria in which reactants and products occupy two or more different phases
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homogeneous equilibria : equilibria in which all reactants and products occupy the same phase
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law of mass action : when a reversible reaction has attained equilibrium at a given temperature, the reaction quotient remains constant
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Le Châtelier’s principle : an equilibrium subjected to stress will shift in a way to counter the stress and re-establish equilibrium
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reaction quotient (Q) : mathematical function describing the relative amounts of reactants and products in a reaction mixture; may be expressed in terms of concentrations (Qc) or pressures (Qp)
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reversible reaction : chemical reaction that can proceed in both the forward and reverse directions under given conditions
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A reversible reaction is at equilibrium when the forward and reverse processes occur at equal rates. Chemical equilibria are dynamic processes characterized by constant amounts of reactant and product species.
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The composition of a reaction mixture may be represented by a mathematical function known as the reaction quotient,Q. For a reaction at equilibrium, the composition is constant, andQis called the equilibrium constant,K.
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A homogeneous equilibrium is an equilibrium in which all components are in the same phase. A heterogeneous equilibrium is an equilibrium in which components are in two or more phases.
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