Honors Gen. Chem. Exam 2

Front 1

thermochemistry

Back 1

the study of relationships between chemistry and energy

Front 2

energy

Back 2

capacity to do work

Front 3

work

Back 3

the result of a force acting through a distance

Front 4

heat

Back 4

the flow of energy caused by a temperature difference

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kinetic energy

Back 5

energy associated with the motion of an object

Front 6

thermal energy

Back 6

energy associated with the temperature of an object

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potential energy

Back 7

energy associated with the position or composition of an object

Front 8

chemical energy

Back 8

the energy associated with the relative positions of electrons and nuclei in atoms and molecules

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law of conservation of mass

Back 9

energy can neither be created nor destroyed

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system

Back 10

portion of the universe which is singled out for investigation

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surroundings

Back 11

everything else in the universe which exists outside the system of investigation

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joule (J)

Back 12

the SI unit for energy

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calorie (cal)

Back 13

the amount of energy required to raise the temperature of 1 g of water by 1 degree C; 1 cal=4.184 J

Front 14

thermodynamics

Back 14

the general study of energy and its interconversions

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first law of thermodynamics

Back 15

the total energy of the universe is constant

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internal energy (E)

Back 16

the sum of the kinetic and potential energies of all of the particles that compose a system

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state function

Back 17

its value depends only on the state of the system, not how the system arrived at that state

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thermal equilibrium

Back 18

the point at which there is no additional net transfer of heat between the system and surroundings

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heat capacity (C)

Back 19

the quantity of heat required to change its temperature by 1 degree C

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specific heat capacity (Cs)

Back 20

the amount of heat required to raise the temperature of 1 gram of the substance by 1 degree C

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pressure-volume work

Back 21

the work that occurs when a volume change takes place against an external pressure

Front 22

calorimetry

Back 22

the experimental procedure used to measure the heat evolved in a chemical reaction

Front 23

bomb calorimeter

Back 23

a piece of equipment designed to measure the change in internal energy for combustion reactions

Front 24

enthalpy (H)

Back 24

the sum of the internal energy and the product of the pressure and volume of a system

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endothermic reaction

Back 25

absorbs heat from its surroundings; positive change in enthalpy

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exothermic reaction

Back 26

gives off heat to its surroundings; negative change in enthalpy

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coffee-cup calorimeter

Back 27

a piece of equipment designed to measure the heat of reaction for reactions at constant pressure

Front 28

Hess's Law

Back 28

the change in enthalpy for a stepwise process is the sum of the enthalpy changes of the steps

Front 29

standard state

Back 29

For a gas: pressure of exactly 1 atm. For a liquid of solid: pressure of 1 atm and the temperature of interest (25 C). For a substance in solution: concentration of 1 M.

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standard enthalpy change

Back 30

change in enthalpy for a process when all reactants and products are in their standard states

Front 31

standard enthalpy of formation

Back 31

the change in enthalpy when 1 mol of a compound forms form its constituent elements in their standard states

Front 32

quantum-mechanical model

Back 32

a model that explains how electrons exist in atoms and how those electrons determine the chemical and physical properties of elements

Front 33

electromagnetic radiation

Back 33

a type of energy embodied in oscillating electric and magnetic fields

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amplitude

Back 34

vertical height of the crest of a wave

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wavelength

Back 35

distance is space between adjacent crests

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frequency

Back 36

the number of cycles that pass through a stationary point in a given period of time

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electromagnetic spectrum

Back 37

includes all the wavelengths of electromagnetic radiation

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gamma ray

Back 38

the form of electromagnetic radiation with the shortest wavelength

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x-ray

Back 39

electromagnetic radiation with wavelengths slightly longer than those of gamma rays

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ultra-violet (UV) radiation

Back 40

electromagnetic radiation with slightly shorter wavelengths than visible light

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visible light

Back 41

those frequencies of electromagnetic radiation that can be detected by the human eye

Front 42

infrared radiation

Back 42

electromagnetic radiation emitted from warm objects, with wavelengths slightly larger than those of visible light

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microwaves

Back 43

electromagnetic radiation with wavelengths slightly longer than those of infrared radiation; used for radar and in microwave ovens

Front 44

radio waves

Back 44

the form of electromagnetic radiation with the longest wavelengths and smallest energy

Front 45

interference

Back 45

the superposition of two or more waves overlapping in space, resulting in either an increase or decrease in amplitude

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constructive interference

Back 46

the interaction of waves from two sources that align with overlapping crests, resulting in a wave of greater amplitude

Front 47

destructive interference

Back 47

the interaction of waves from two sources aligned so that the crest of one overlaps the trough of the other, resulting in cancellation

Front 48

diffraction

Back 48

the phenomena by which a wave emerging from an aperture spreads out to form a new wave front

Front 49

photoelectric effect

Back 49

the observation that many metals emit electrons when light shines upon them

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photon (quantum)

Back 50

the smallest possible packet of electromagnetic radiation with an energy equal to hv

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emission spectrum

Back 51

the range of wavelengths emitted by a particular element; used to identify that element

Front 52

de Broglie relation

Back 52

the observation that the wavelength of a particle is inversely proportional to its momentum

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complementary properties

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those properties that exclude one another, i.e. the more you know about one, the less you know about the other. The wave nature and particle nature of electrons are complementary

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Heisenberg's uncertainty principle

Back 54

The principle stating that due to the wave-particle duality, it is fundamentally impossible to precisely determine both the position and velocity of a particle at a given moment in time

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deterministic

Back 55

a characteristic of the classical laws of motion, which imply that present circumstances determine future events

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indeterminacy

Back 56

the principle that present circumstances do not necessarily determine future events in the quantum-mechanical realm

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orbital

Back 57

a probability distribution map showing where the electron is likely to be found

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wave function

Back 58

a mathematical function that describes the wavelike nature of electrons

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quantum number

Back 59

one of the four interrelated numbers that determine the shape and energy of orbitals, as specified by a solution of the Schrodinger equation

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principle quantum number (n)

Back 60

an integer that specifies the overall size and energy of an orbital. The higher the value of n, the greater average distance between the electron and the nucleus and the higher the energy

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angular momentum quantum number (l)

Back 61

an integer that determines the shape of the orbital

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magnetic quantum number (Ml)

Back 62

an integer that specifies the orientation of an orbital

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principle level (shell)

Back 63

the group of orbitals with the same value of n

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sublevel (subshell)

Back 64

those orbitals in the same principle level with the same value of n and l

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probability density

Back 65

the probability (per unit volume) of finding the electron at a point in space as expressed by a three-dimensional plot of the wave function squared

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node

Back 66

a point where the wave function, and therefore the probability density and radial distribution function, all go through zero

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periodic property

Back 67

a property of an element that is predictable based on an element's position in the periodic table

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electron configuration

Back 68

a notation that shows the particular orbitals that are occupied by electrons in an atom

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ground state

Back 69

lowest energy state

Front 70

orbital diagram

Back 70

a diagram which gives information similar to an electron configuaration, but symbolizes an electron as an arrow in a box representing an orbital, with the arrow's direction denoting the electron's spin

Front 71

electron spin

Back 71

a fundamental property of electrons; spin can have a value of + or -1/2

Front 72

spin quantum number (Ms)

Back 72

the fourth quantum number, which denotes the electron's spin as either 1/2 (arrow up) or -1/2 (arrow down)

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Pauli exclusion priciple

Back 73

the principle that no two electrons in an atom can have the same four quantum numbers

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degenerate

Back 74

a term describing two or more electron orbitals with the same value of n that have the same energy

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shielding

Back 75

the effect on an electron of repulsion by electrons in lower-energy orbitals that screen it from the full effects of nuclear charge

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effective nuclear charge (Zeff)

Back 76

the actual nuclear charge experienced by an electron, defined as the charge of the nucleus plus the charge of the shielding electrons

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penetration

Back 77

the phenomenon of some higher-level atomic orbitals having significant amounts of probability within the space occupied by orbitals of lower energy level.

Front 78

aufbau principle

Back 78

the principle that indicates the pattern of orbital filling in an atom

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Hund's rule

Back 79

the principle stating that when electrons fill degenerate orbitals they first fill them singly with parallel spins

Front 80

valence electrons

Back 80

those electrons that are important in chemical bonding. For main-group elements, the valence electrons are those in the outermost principle energy level

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core electrons

Back 81

those electrons in a complete principle energy level and those in complete d and f sublevels

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van der Waals radius (nonbonding atomic radius)

Back 82

defined as one-half the distance between the centers of adjacent, nonbonding atoms in a crystal

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covalent radius (bonding atomic radius)

Back 83

defined in nonmetals as one-half the distance between two atoms bonded together, and in metals as one-half the distance between two adjacent atoms in a crystal of the metal

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atomic radius

Back 84

a set of average bonding radii determined from measurements on a large number of elements and compounds

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paramagnetic

Back 85

the state of an atom or ion that contains unpaired electrons and is, therefore, attracted by an external magnetic field

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diamagnetic

Back 86

the state of an atom or ion that contains only paired electrons and is, therefore, slightly repelled by an external magnetic field

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ionization energy (IE)

Back 87

the energy required to remove an electron from an atom or ion in its gaseous state

Front 88

electron affinity (EA)

Back 88

the energy change associated with the gaining of an electron by an atom in its gaseous state