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Flashcards in Test 2 Deck (73):
1

surface tension

The energy required to increase the surface area of a liquid by a given amount

2

capillarity

A property that results in a liquid rising through a narrow space against the pull of gravity

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viscosity

A measure of the resistance of liquid to flow

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crystalline solid

Solid with a well-defined shape because of the orderly arrangement of the atoms, molecules, or ions.

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amorphous solid

A solid that has a poorly defined shape because it lacks extensive molecular-level ordering of its particles.

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lattice

The three dimensional arrangement of points created by choosing each point to be at the same location within each particle of a crystal; thus, the lattice consists of all points with identical surroundings

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unit cell

The smallest portion of a crystal that , if repeated in all three directions, gives the crystals

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coordination number

In a crystal, the number of nearest neighbors surrounding a particle. In a complex, the number of ligand atoms bonded to the central metal ion.

9

simple cubic unit cell

A unit cell in which a particle occupies each corner of a cube

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body-centered cubic unit cell

A unit cell in which a particle lies at each corner and in the center of a cube

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face-centered cubic unit cell

A unit cell in which a particle occurs at each corner and in the center of each face of a cube.

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packing efficiency

The percentage of the available volume occupied by atoms, ions, or molecules in a unit cell

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hexagonal closet packing

A crystalline structure based on the hexagonal unit cell in which the layers have an abab pattern.

14

cubic closet packing

A crystal structure based on the face-centered cubic unit cell in which the layers have an abcabc pattern.

15

x-ray diffraction analysis

An instrumental technique used to determine dimensions of crystal structure by measuring the diffraction patterns caused by x-rays impinging on the crystal

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atomic solid

A solid consisting of individual atoms held together by dispersion forces; the frozen noble gases are the only examples.

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molecular solid

A solid held together by intermolecular forces between individual molecules.

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ionic solid

A solid whose unit cell contains cations and anions

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metallic solid

A solid whose individual atoms are held together by metallic bonding

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network covalent solid

A solid in which all the atoms are bonded covalently so that individual molecules are not present

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electron-sea model

A qualitative description of metallic bonding proposing that metal atoms pool their valence electrons into a delocalized "sea" of electrons in which the metal cores are submerged in an orderly array.

22

band theory

An extension of molecular orbital theory that explains many properties of metals and other solids, in particular, the differences in electrical conductivity of conductors, semiconductors, and insulators.

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valence band

In band theory, the lower energy portion of the band of molecular orbitals, which is filled with valence electrons.

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conduction band

In band theory, the empty, higher energy portion of the band of molecular orbitals into which electrons move when conducting heat and electricity

25

conductor

A substance that conducts an electric current well.

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semiconductor

A substance whose electrical conductivity is poor at room temperature but increases significantly with rising temperature

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insulator

A substance that does not conduct an electric current.

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superconductivity

The ability to conduct a current with no loss of energy to resistive heating.

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solute

The substance that dissolves in the solvent

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solvent

The substance in which the solute dissolves.

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miscible

Soluble in any proportion

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solubility

The maximum amount of solute that dissolves in a fixed quantity of a particular solvent at a specific temperature

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like-dissolves-like rule

An empirical observation stating that substances having similar kinds of intermolecular forces dissolve in each other

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hydration shell

The oriented cluster of water molecules that surrounds an ion in aqueous solution

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ion-induced dipole force

The attractive force between an ion and the dipole it induces in the electron cloud of a nearby non polar molecule

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dipole-induced dipole force

The intermolecular attraction between a polar molecule and the oppositely charged pole it induces in a nearby molecule

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alloy

A mixture of elements with metallic properties that is typically a solid-solid solution.

38

heat of solution

The enthalpy change occurring when a solution forms from solute and solvent

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solvation

The process of surrounding a solute particle with solvent particles

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hydration

Solvation in water

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heat of hydration

The enthalpy change occurring when 1mol of a gaseous species is hydrated

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charge density

The ratio of the charge of an ion to its volume

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entropy

A thermodynamic quantity related to the number of ways the energy of a system can be dispersed through the motions of its particles

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saturated solution

A solution that contains the maximum amount of dissolved solute at a given temperature

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unsaturated solution

A solution in which more solute can be dissolved at a given temperature

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supersaturated solution

An unstable solution in which more solute is dissolved than in a saturated solution

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Henry's Law

A law stating that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid

48

molality

A concentration term expressed as number of moles of solute dissolved in 1000g of solvent.

49

mass percent

The fraction by mass expressed as a percentage

50

volume percent

A concentration term defined as the volume of solute in 100 volumes of solution.

51

mole fraction

A concentration term expressed as the ratio of moles of one component of a mixture to the total moles present.

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colligative property

A property of a solution that depends on the number, not the identity, of solute particles.

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electrolyte

A substance that conducts a current when it dissolves in water.

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non electrolyte

A substance whose aqueous solution does not conduct an electric current

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vapor pressure lowering

The decrease in the vapor pressure of a solvent caused by the presence of dissolved solute particles.

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Raoul's law

A low stating the the vapor pressure of solvent above a solution equals the mole fraction of solvent times the vapor pressure of pure solvent.

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ideal solution

A solution whose vapor pressure equals the mole fraction of the solvent times the vapor pressure of the pure solvent.

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boiling point elevation

The increase int he boiling point of a solvent caused by the presence of dissolved solute

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freezing point depression

The lowering of the freezing point of a solved caused by the presence of dissolved solute particles.

60

semipermeable membrane

A membrane that allows solvent, but not solute, to pass through.

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osmosis

The process by which solvent flows through a semipermeable membrane from a dilute to a concentrated solution.

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osmotic pressure

The pressure that results from the ability of solvent, but not solute, particles to cross a semipermeable membrane. The pressure required to prevent the net movement of solvent across the membrane

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ionic atmosphere

A cluster of ions of net opposite charge surrounding a given ion in solution.

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chemical kinetics

The study of the rates and mechanism of reactions.

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reaction rate

The change in the concentrations of reactants with time.

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average rate

The change in concentration of reactant divided by a finite time period.

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instantaneous rate

The reaction rate at a particular, given by the slope of a tangent to a plot of reactant concentration vs. time.

68

initial rate

The instantaneous rat occurring as soon as the reactants are mixed,, that is, at t=0.

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rate law

An equation that expresses the rate of a reaction as a function of reactant concentrations

70

rate constant

The proportionality constant that relates reaction to rate to reactant concentrations.

71

reaction orders

The exponent of a reactant concentration in a rate law that shows how the rate is affected by changes in that concentration

72

integrated rate law

A mathematical expression for reactant concentration a s a function of time.

73

half-life

In chemical processes, the time required for half the initial reactant concentration to be consumed.