Chm 113 - Ch 4-6 Exam 2 Notecards Terms And Definitions

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aqueous solutions

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solutions in which water is the dissolved medium

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solvent

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the component of the solution that is present in the greatest quantity

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solute

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component other than the solvent

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electrolyte

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any substance whose aqueous solution contains ions

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nonelectrolyte

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any substance that forms a solution containing no ions

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strong electrolytes

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electrolytes that are present in solution entirely as ions

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weak electrolytes

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electrolytes that are present partly as ions and partly as molecules

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solvation

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the interaction of ions with polar solvent molecules

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precipitation reactions

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those in which an insoluble product (precipitate) forms.

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precipitate

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insoluble product

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solubility

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the amount that dissolves in a given quantity of solvent

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exchange reactions (metathesis reactions)

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cations and anions appear to exchange partners

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molecular equation

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complete formulas of all reactant and products

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complete ionic equation

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shows all dissolved strong electrolytes as their component ions

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net ionic equation

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ions that go through the reaction unchanged (spectator ions) are omitted

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spectator ions

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ions that go through a reaction unchanged

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acids

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proton donors, they increase the concentration of H+(aq) in aqueous solutions which they are added.

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bases

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proton acceptors, they increase the concentration of OH-(aq) in aqueous solutions.

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strong acids

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strong electrolytes

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strong bases

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strong electrolytes

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weak acids

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weak electrolytes

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weak bases

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weak electrolytes

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neautralization reaction

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when solutions of acids and bases are mixed. (between an acid and a metal hydroxide produces water and a salt)

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oxidation

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loss of electrons by a substance

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reduction

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gain of electrons by a substance

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oxidation number

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keep track of electrons during chemical reactions are are assigned to atoms using specific rules

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concentration

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expresses the amount of a solute dissolved in the solition

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molarity

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the number of moles of solute per liter of solution

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titration

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combine a solution of a known concentration with a solution of unknown concentration to determine the unknown concentration of quantity of solute in the unknown.

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equivalence point

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the point in the titration at which stoichiometrically equivalent quantities of reactants are brought together

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thermodynamics

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study of energy and it's transformations

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thermochemistry

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the transformations of energy - especially heat - during chemical reactions.

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kinetic energy

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energy due to the motion of the object

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potential energy

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the energy that an object possesses by virtue of its position relative to other objects

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joule

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SI unit of energy

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calorie

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another common unit of energy

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system

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when we study thermodynamic properties, we define a specific amount of matter as the...

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surroundings

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everything outside the system

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work

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the energy expanded to move an object against a force

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heat

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the energy that is transferred from a hotter object to a colder one

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energy

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the capacity to do work or to transfer heat

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internal energy

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the sum of all kinetic and potential energies of its component parts

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first law of thermodynamic

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the change in the eternal energy of a system (deltaE) is the sum of the heat (q) transferred into or out of the system and the work (w) done on or by the system (deltaE=q+w)

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endothermic

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the system absorbs heat from the surroundings

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exothermic

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the system releases heat to the surroundings

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state function

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the value of any state function depends only on the state or condition of the system and not on the details of how it came to be in the state

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pressure-volume (P-V) work

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when gas is produced or consumed in a chemical reaction occuring at constant pressure, the system may perform pressure-volume (P-V) work against the prevailing pressure of the surroundings.

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enthalpy

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(H) related to energy: (H=E+PV)

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enthalpy of reaction

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the enthalpy of the products minus the enthalpy of the reactants: (Hproducts-Hreactants).

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caliometry

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the amount of heat transferred between the system and the surroundings is measured experimentally by...

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calorimeter

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measures the temperature change accompanying a process

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heat capacity

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the amount of heat required to raise its temperature by 1K

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molar heat capacity

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heat capacity for one mole

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specific heat

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for one gram of a substance

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bomb calorimeter

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constant-volume calorimetry is carried out in a vessel of fixed volume

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Hess's law

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states that if a reaction is carried out in a series of steps, (deltaH) for the reaction will be equal to the sum of the enthalpy changes for the steps.

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enthalpy of formation

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(delta(H) subscript(f)) of a substance is the enthalpy change for the reaction in which the substance is formed from its constituent elements

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standard states

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usually enthalpies are tabulated for reactions where reactants and products are in their...

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standard enthalpy change

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(delta(H) degree sign) is the enthalpy change when all reactants and products are in their standard states

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standard enthalpy of formation

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(delta(H) subscript(f) degree sign) of a substance is the change in enthalpy for the reaction that forms one mole of the substance from its elements in their standard states

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fuel value

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the heat released when one gram of the substance is combusted

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electronic structure

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describes the energies and arrangement of electrons around the atom. Much of what is known about the electronic structure of atoms was obtained by observing the interaction of light with matter.

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electromagnetic radiation

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(also known as radiant energy) move through a vaccum at the speed of light, c=2.998x10^8 m/s. has both electric and magnetic components that vary periodically in wave-like fashion. the wave characteristics of radiant energy allow it to be described in terms of wavelength (lambda) and frequency (v) which are interrelated (lambda X v = c)

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quantum

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minimum amount of radiant energy that an object can gain or lose is related to the frequency of the radiation E=hw. this smallest quantity is called a ______ of energy.

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Planck constant

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constant h.

h = 6.626 x 10^(-34) J-s

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photoelectric effect

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the emission of electrons from metal surfaces when exposed to light

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photons

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the smallest increment (a quantum) of radiant energy; a photon of light with frequency (v) has an energy equal to (hv) (Section 6.2)

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spectrum

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the distribution among various wavelengths of the radiant energy emitted or absorbed by an object (section 6.3)

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continuous spectrum

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a spectrum that contains radiation distributed over all wavelengths.

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line spectrum

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a spectrum that contains radiation at only certain specific wavelengths (section 6.3)

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principal quantum number

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the energy of the electron in the hydrogen atom depends on the value of a quantum number, n, called the ______ (section 6.3)

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ground state

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the lowest-energy, or most stable, state. (section 6.3)

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excited state

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a higher energy state than the ground state. (section 6.3)

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matter waves

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the term used to describe the wave characteristics of a moving particle. (section 6.4)

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momentum

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the product of the mass, m, and velocity, v, of an object (section 6.4)

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uncertainty principle

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a principle state there is an inherent uncertainty in the precision with which we can simultaneously specify the position and momentum of a particle. this uncertainty is significant only for particles of extremely small mass, such as electrons (section 6.4)

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wave functions

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a mathematical description of an allowed energy state (an orbital) for an electron in the quantum mechanical model of the atom; it is usually symbolized by the greek letter (___) (section 6.5)

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probability density (____^2)

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a value that represents the probablity that an electron will be found at a given point in space. also called electron density. (section 6.5)

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electron density

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the probability of finding an electron at any particular point in an atom; this probability is equal to (____^2) the square of the wave function. also called the probability density (section 6.5)

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orbitals

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an allowed energy state of an electron in the quantum mechanical model of the atom; the term orbital is also used to described the spatial distribution of the electron. An orbital is defined by the values of three quantum numbers: n, l, and m1 (section 6.5)

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angular momentum quantum number

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indicated by the letters s, p, d, f, and so on, corresponding to the values of 0, 1, 2, 3...

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magnetic quantum number

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relates to the orientation of the orbital in space.

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subshell

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one or more orbitals with the same set of quantum numbers n and l. For example, we speak of the 2p subshell (n=2, l=1), which is composed of three orbitls (2px, 2py, and 2pz) (section 6.5)

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radial probability function

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the probability that the electron will be found at a certain distance from the nucleus (section 6.6)

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nodes

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points in an atom at which the electron density is zero. for example, the node in a 2s orbital is a spherical surface (section 6.6)

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degenerate

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a situation in which two or more orbitals have the same energy. (section 6.7)

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electron spin

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a property of the electron that makes it behave as though it were a tiny magnet. the electron behaves as if it were spinning on its axis; electron spin is quantized. (section 6.7)

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spin magnetic quantum number (ms)

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a quantum number associated with th elextron spin; it may have values of +(1/2) and -(1/2) (section 6.7)

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Pauli exclusion principle

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a rule stating that no two electrons in an atom may have the sam four quantum numbers (n, l, m1, and ms). as a reflection of this principle, there can be no mere than two electrons in any one atomic orbital. (section 6.7)

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electron configuration

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the arrangement of electrons in the orbitals of an atom or molecule (section 6.8)

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orbital diagram

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pictoral depiction of the arrangement of electrons (section 6.8 and 6.9)

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Hund's rule

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a rule stating that electrons occupy degenerate orbitals in such a way as to maximize the number of electrons with the same spin. in other words, each orbital has one electron place in it before pairing of electrons in orbitals occurs. (section 6.8)

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valence electrons

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the outermost electrons of an atom; those that occupy orbitals not occupied in the nearest noble-gas element of lower atomic number. the valence electrons are the ones the atom uses in bonding. (section 6.8)

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core electrons

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the electrons that are not in the outermost shell of an atom.

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representative (or main group) elements

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an element from within the s and p blocks of the periodic table (figure 6.29) (section 6.9)

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transition elements (transition metals)

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elements in which the d orbitals are partially occupied. (section 6.8)

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lanthanide (rare earth) elements

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elements in which the 4f subshell is only partially occupied. (sections 6.8 and 6.9)

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actinide elements

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element in which the 5f orbitals are only partially occupied. (section 6.8)

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f-block metals

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lanthanide and actinide elements in which the 4f or 5f orbitals are partially occupied. (section 6.9)