midterm Exam Flashcards
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Q
Element
A
A substance consisting if atoms of the same atomic number. Historically defined as a substance that cannot be separated into simpler substances be chemical means
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Matter
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Anything that occupies space and has mass; the physical material of the universe
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Chemistry
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The scientific discipline that studies the composition, properties, and transformations of matter
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Atom
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The smallest representative particle of an element
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Property
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A characteristic that gives a sample of matter its unique identity
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Molecule
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A chemical combination of two or more atoms
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Gas
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Matter that has no fixed volume or shape; its conforms to the volume and shape of its container
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Liquid
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Matter that has a distinct volume but no specific shape
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Solid
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Matter that has both a definite shape and a definite volume
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States of matter
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The tree forms that matter can assume: solid, liquid, and gas
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Pure substance
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Matter that has a fixed composition and distinct properties
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Element
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A substance consisting of atoms of the same atomic number. Historically defined as a substance that cannot be separated into simpler substances by chemical means
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Compound
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A substance composed if two or more elements united chemically in definite proportions
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Law of constant composition (law of definite proportions)
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That every elemental composition of a pure compound is always the same, regardless of its source
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Mixture
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A combination of two or more substances in which each substance retains its own chemical identity
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Solutions
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A mixture of substances that had a uniform composition; a homogenous mixture
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Physical properties
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Properties that can be measured without changing the composition of a substance ex: color, freezing point, density
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Chemical properties
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Properties that describe a substances composition and its reactivity; how the substance reacts or changes into other substances ex: flammability, chemical stability (in a given environment)
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Physical change
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Changes that occur without no change in chemical composition ex:phase change
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Changes state
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Transformations of matter from on state to a different one ex:gas to liquid
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Chemical change
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Processes in which one or more substances are converted into other substances (chemical reactions)
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Intensive properties
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A property that is independent of the amount of material considered ex:density
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Extensive properties
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A property that depends on the amount of material considered ex: mass, volume
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Scientific method
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The general process of advancing scientific knowledge by making experimental observations and by formulating hypothesis, theories, and laws
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Scientific law
A concise verbal statement or a mathematical equation that summarizes a wide range of observations and experiences
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Hypothesis
A tentative explanation of a series of observation or of a natural law
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Theory
A tested model or explanation that satisfactorily accounts for a certain set of phenomena
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Mass
A measure of the amount of material in an object. It measures the resistance of an object to being moved.. Mass=kg
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Kelvin scale
The absolute temperature scale; the SI unit for temperature is the kelvin. Zero in the kelvin scale corresponds to. degree celcius+273
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Density
The ratio of an objects mass to its volume
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Celcius-Fahrenheit
F=Cx 9/5 +32
| C=(f-32) x 5/9
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Precision
The closeness of agreement among several measurements of the same quantity; the reproducibility of a measurement
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Accuracy
A measure of how closely individual measurements agree with the correct value
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Atoms
The smallest representative particle of an element
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Subatomic particles
Particles such as protons, neutrons, and electrons that are smaller than an atom
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Cathode rays
Streams of electrons that are produced when a high voltage is applied to electrodes in an evacuated tube
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Radioactivity
Possessing radioactivity, the spontaneous disintegration of an unstable atomic nucleus with accompanying emission of radiation
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Nuclear model
Model of the atom with nucleus containing protons and neutrons and with electrons in the space outside the nucleus
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Nucleus
The very small, very dense, positively charged portion of an atom; of is composed of protons and neutrons
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Proton
A positively charged subatomic particle found in the nucleus of an atom
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Neutron
An electrically neutral particle found in the nucleus of an atom; it has approximately the same mass as a proton
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Electrons
A negatively charged subatomic particle found outside the atomic nucleus; it is a part if all atoms. An electron has a mass times that of a proton
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Electronic charge
The negative charge carried by an electron; it has a magnitude of .
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Angstrom
Si units to measure atomic dimensions
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Atomic number
The number of protons in the nucleus of an atom of an element
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Mass number
The sum of the number of protons and neutrons in the nucleus of a particular atom
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Atomic weight
The average mass of the atom of an element in atomic mass units (amu); it is numerically equal to the mass in grams of one mole of the element
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Mass spectrometer
An instrument used to measure the precise masses and relative amounts of atomic and molecular ions
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Group
Elements that are in the same column of the periodic table; elements within the same group if family exhibit similarities in their chemical behavior
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Period
The row of elements that lie in a horizontal row in the periodic table
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Metallic elements (metals)
Elements that are usually solids at room temperature, exhibit high electrical and heat conductivity, and appear lustrous. Most of the elements in the periodic table are metals
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Nonmetallic elements (nonmetals)
Elements in the upper right corner of the periodic tae; nonmetals differ from metals in their physical and chemical properties
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Metalloids
Elements that lie along the diagonal line separating the metal from the nonmetals in the periodic table; the properties of metalloids are intermediate between those of metals and nonmetals
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Molecules
A chemical combination of two or more atoms
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Molecular compound
A compound that consists of molecules
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Diatomic molecule
A molecule composed of only two atoms
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Chemical formula
A notion that uses chemical symbols with numerical subscripts to convey the relative proportions of atoms of the different elements in a substance
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Empirical formula
A chemical formula that shows the kinds of atoms and their relative numbers in a substance in the smallest possible whole-number ratio
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Molecular formula
A chemical formula that indicates the actual number of atoms if each element in one molecule of a substance
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Structural formula
A formula that shows not only the number and kinds of atoms on the molecule but also the arrangement(connections) of the atoms
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Ions
Electrially charged atom or group of atoms(polyatomic ion); ions can be positively or negatively charged, depending on whether electrons are lost (positive) or gained (negative) by the atoms
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Ionic compounds
A compound composed of cations and anions
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Polyatomic ion
An electrically charged group of two or more atoms
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Chemical nomeclature
The rules used in naming substances
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Oxyanion
A polyatomic anion that contains one or more oxygen atoms
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Organic chemistry
The study of carbon-containing compounds, typically containing carbon-carbon bonds
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Hydrocarbons
Compounds composed of only carbon and hydrogen
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Alkanes
Compounds of carbon and hydrogen containing only carbon-carbon single bonds
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Alcohol
An organic compound obtained by substituting a hydroxyl group for a hydrogen on a hydrocarbon
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Isomers
Compounds whose molecules have the same overall composition but different structures
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Stoichiometry
The relationships among the quantities of reactants and products involved in chemical reactions
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Chemical equation
A representation if a chemical reaction using the chemical formulas of the reactant and products; a balanced equation contains equal numbers of atoms of each element on both sides of the equation
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Reactant
A starting substance in a chemical reaction; it appears to the left if the arrow in a chemical equation
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Products
A substance produced in a chemical reaction; it appears to the right of the arrow in a chemical equation
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Combination reaction
A chemical reaction in which two or more substances combine go form a single product
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Decomposition reaction
A chemical reaction in which a single compound reacts to give two or more products
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Combustion reaction
A chemical reaction the proceeds with evolution of heat and usually also a flame; most combustion involves reaction with oxygen, as in the burning of a match
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Formula weight
The mass of the collection of atoms represented by a chemical formula.
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Molecular weight
The mass of the collection of atoms represented by the chemical formula for a molecule
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Molar mass
The mass of one mole of a substance in grams; its numerically equal to the formula weight in atomic mass units
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Limiting reactant (limiting reagent)
The reactant present in the smallest stoichiometric quantity in a mixture of reactants; the amount of product that can form is limited by the complete consumption of the limiting reactant
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Theoretical yield
The quantity of product that is calculated to form when all of the limiting reagent reacts
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Percent yield
The ratio of the actual (experimental) yield of a product to its theoretical (calculated) yield, multiplied by 100
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Aqueous solution
A solution in which water is the solvent
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Solvents
The dissolving medium of a solution; it is normally the component of a solution present in the greater amount
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Solute
A substance dissolved in a solvent to form a solution; it is normally the component of a solution present in the smaller amount
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Electrolyte
A solute that produces ions in a solution; an electrolytic solution conducts an electric current
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Nonelectrolyte
A substance that does not ionize in water and consequently gives a nonconducting solution
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Strong electrolyte
A substance(strong acid, strong base, most salts) that is completely ionized in solution
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Weak electrolyte
A substance that only partly ionizes in solutions
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Solvation
The clustering of solvent molecules around a solute particle
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Chemical equilibrium
A state of dynamic balance in which the fate f
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Precipitation reaction
A reaction that occurs between substances in a solution in which one of the products is insoluble
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Precipitate
An insoluble substance that forms in, and seperates from a solution
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Solubility
The amount if a substance that dissolves un a given quantity of solvent at a given temperature to form a saturated solution
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Exchange/ metathesis reaction
A reaction between compounds that when written as a molecular equation appears to involve the exchange of ions between the two reactants
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Molecular equation
A chemical equation in which the formula for each substance is written without regard for whether it is an electrolyte or a nonelectrolyte
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Complete ionic equation
A chemical equation in which dissolved strong electrolytes (such as dissolved ionic compounds) are written as a separate ions
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Net ionic equation
A chemical equation for a solution reaction in which soluble strong electrolytes are written as ions and spectator ions are omitted
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Spectator ions
Ions that go through a reaction unchanged and that appear on both sides if the complete ionic equation
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Acid
A substance that is able to donate a ion(a proton) and, hence, increases the concentration of when it dissolves in water
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Bases
A substance that is an acceptor; a base produces an excess if ions when it dissolves in water
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Strong acid
An acid that ionizes completely in water
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Strong base
A base that ionizes completely in water
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Weak acid
An acid that only partly ionizes in water
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Weak base
A base that only partly ionizes in water
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Neutralization reaction
A reaction in which an acid and a base react in stoichiometrically equivalent amounts; the neutralization reaction between an acid and. metal hydroxide produces water and a salt
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Salt
An ionic compound formed by replacing one or more hydrogens of an acid by other cations
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Oxidation
A process in which a substance loses one or more electrons
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Reduction
A process in which a substance gains one or more electrons
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Oxidation number
Keep track of electrons during chemical reactions and are assigned to atoms using specific rules
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Redox reactions
A chemical reaction in which the oxidation states of certain atoms change
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Displacement reaction
A reaction in which an element reacts with a compound, displacing and element from it
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Activity series
A list of metals in order of decreasing ease of oxidation
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Concentration
The quantity of solute present in a given quantity of solvent or solution
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Molarity
The concentration of a solution expressed as moles if solute per liter of solution
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Dilution
A process of preparing a less concentrated solution from a more concentrated one by adding solvent
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Titration
The process of reacting a solution of unknown concentration with one of known concentration (a standard solution)
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Standard solution
A solution of known concentration
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Equivalence point
The point in titration at which the added solute reacts completely with the solute present in the solution
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Indicator
A substance added to a solution that changes color when the added solute has reacted with all the solute present in the solution.
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Thermodynamics
The study of energy and its transformation
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Thermochemistry
The relationship between chemical reactions and energy changes
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Kinetic energy
The energy that an object possesses by virtue of its motion
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Potential energy
The energy that an object possesses as a result of its composition or its position with respect to another object
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Joule
The Si unit of energy. Related unit=calorie
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calorie
A unit of energy, it is the amount of energy needed to raise the temperature of 1g of water.
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System
In thermodynamics, the position of the universe that we single out for study. We must be careful to state exactly what the system contains and what transfers of energy it may have with its surroundings
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Surroundings
In thermodynamics, everything that lies outside the system that we study
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Work
The movement of an object against some force
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Force
A push or pull
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Heat
The flow of energy from a body at high temperature to one at lower temperature when they are placed in thermal contact
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Energy
The capacity to do work or transfer heat
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Internal energy
The total energy possessed by a system. When a system undergoes a change, the change in internal energy, is defined as the heat, q, added to the system plus the work, w, done in the system by its surroundings
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1st law of thermodynamics
Energy is conserved in any process.
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Endothermic process
A process in which a system absorbs heat from its surroundings
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Exothermic process
A process in which a system releases heat to its surroundings
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state function
A property of a system that is determined by its state or condition and not by how it got to that state; its value is fixed when temperature, pressure, composition, and physical for are specified; p, v, t, e and h
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Pressure-volume work
Work performed by expansion of a gas against a resisting pressure
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Enthalpy
A quantity defined by the relationship the enthalpy change. For a reaction that occurs at constant pressure is the heat evolved or absorbed in the reaction
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Enthalpy of reaction
The enthalpy change associated with a chemical reaction
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Calorimetry
The experimental measurement of hear produced in chemic and physical processes
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Calormeter
An apparatus that measures the heat released or absorbed in a chemical or physical process
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Heat capacity
The quantity of heat required to raise the temperature of a sample of matter by (or 1 K)
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Molar heat capacity
The heat required to raise the temperature of one mole of a substance by 1 K
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Specific heat (Cs)
The heat capacity of 1 g of a substance; the heat required to raise the temp if 1g of a substance 1K
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Bomb calorimeter
A device for measuring the heat evolved in the combustion of a substance under constant-volume conditions
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Hess's law
The heat evolved in a give process can be expressed as the sum of the heats of several processes that, when added, yield this process if interest
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Enthalpy of formation
The enthalpy change that accompanies the formation of a substance from the most stable forms of its component elements that
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Standard enthalpy change
The change in enthalpy in a process when all reactants and products are in their stable forms at 1atm pressure and a specified temperature, commonly
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Standard enthalpy of formation
The change in enthalpy that accompanies the formation of one mole of a substance from its elements, with all substances in their standard states
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Fuel value
The energy released when 1g of substance is combusted
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Fossil fuels
Coal, oil, and natural gas, which are presently our major sources of energy
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Natural gas
A naturally occurring mixture of gaseous hydrocarbon compounds composed of hydrogen and carbon
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Petroleum
A naturally occurring combustible liquid compared if hundreds of hydrocarbons and other organic compounds
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Coal
A naturally occurring solid containing hydrocarbons if high molecular weight, as well as compounds containing sulfur, oxygen, and nitrogen
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Renewable energy sources
Energy such as solar energy, wind energy, and hydroelectric energy derived from essential inexhaustible sources
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Electronic structure
The arrangement of electrons in an atom or molecule
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Electromagnetic radiation(radiant energy)
A form of energy that has wave characteristics and that propagates through a vacuum at the characteristic speed of .
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Wavelength
The distance between identical points on successive waves
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Frequency
The number of times per second that one complete wavelength passes a given point
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Quantum
The smallest increment of radiation energy that may be absorbed or emitted; the magnitude of radiant energy ise
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Planck's constant (h)
The constant that relates the energy and frequency of a photon
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Photoelectric effect
The emission of electrons from a metal surface induced by light
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Photon
The smallest increment (quantum) of radiant energy; a photon of light with frequency has an energy =hv
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Spectrum
The distribution among various wavelengths of the radiant energy emitted or absorbed by an object
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Continuous spectrum
A spectrum that contains radiation distributed over all wavelengths
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Line spectrum
A spectrum that contains radiation at only certain specific wavelengths
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ground state
The lowest-energy, or most stable, state
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Excited state
A higher energy state than the ground state
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Matter waves
The term used to describe the wave characteristics of a moving particle
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Uncertainty principle
A principal stating 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 pf extremely small mass, such as electrons
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Wave functions
A mathematical description of an allowed state (an or orbital) for an electron in the quantum mechanical model of the atom
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Probability density (electron density)
A value that represents the probability that an electron will be found at a given point in space
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Electron density
The probability of finding an electron at any particular point in an atom; this probability is equal to, the square of the wave function. Also called the probability density
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Orbitals
An allowed energy state of an electron in the quantum mechanical model of the atom; the term orbital is also used to describe the spatial distribution of the electron. An orbital is defined by the values of three quantum numbers n, i, and m
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Electron shells
A collection of orbitals that have the same value of n (3s, 3p, 3d)
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Subshell
One or more orbitals with the same set of quantum numbers n and i
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Radial probability function
The probability that the electron will be found at a certain distance from the nucleus
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Nodes
Point in an atom at which the electron density is zero ex. Nodes in 2s=spherical surface
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Degenerate
A situation in which two or more have the same energy
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Electron spins
A property of the electron that make it behave as though it were a tiny magnet. The electron behaves as if it were spinning on its axis; electron spin is quantized
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Spin magnetic quantum number
A quantum number associated with the electron spin; it may have values of or +/- 1/2
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Pauli exclusion principle
A rule stating that no two electrons in an atom mat have the same four quantum numbers ( n, l, m and m)... As a result bit more that two electrons in any atomic orbital
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Electron configuration
The arrangement of electrons in the orbitals of an atom or molecule
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Hunds rule
A rule stating that electrons occupy degenerate orbitals in such a way as to maximize the number of electrons with the same spin. In the other words, each orbital has one electron placed in it before pairing of electrons in orbitals occurs
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Valence electrons
The outermost electrons of an atom; those that occupy orbitals not occupied in the nearest noble-gas element of lower atomic number. Te valence electrons are the ones the atom uses in bonding
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Core electrons
The electrons that are not in the outermost shell of an atom
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Representatives (main group) element
An element from within the s and p blocks if the periodic table
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Transition elements (transition metals)
Element in Which the d orbitals are partially occupied
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Ianthanide (rare earth) elements
Element in which the 4f subshell is only partially occupied
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F block metals
Lanthanide and actinide element in which the 4f or 5f orbitals are partially occupied
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Valence orbitals
Orbitals that contain the outershell electrons of an atom
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Effective nuclear charge
The net positive charge experienced by an electron in a many-electron atom; this charge is not the full nuclear charge because there is some shielding f the nucleus by the other electrons in the atom
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Bonding atomic radius
The radius of an atom S defined by the distances separating it from other atoms to which it is chemically bonded
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Isoelectronic series
A series of atoms, ions, or molecules having the same number of electrons
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Ionization energy
The energy required to remove an electron from a gaseous atom when the atom is in its ground state
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Electron affinity
The energy change that occurs when an electron is added to a gaseous atom or ion
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Metallic character
The extent to which an element exhibits the physical and chemical properties characteristics of metals, for example, luster, malleability, ductility, and good thermal and electrical conductivity
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Alkali metals
Member of group 1A in the periodic table
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Alkaline earth metals
Members of group 2a in the periodic table
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Hydride ion
An ion formed by the addition of an electron to a Hydrogen atom
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Ozone
The name given to O3, an allotrope of oxygen
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Halogens
Members of group 7A in the periodic table
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Noble gases
Members of group 8A in the periodic table
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Chemical bond
A strong attractive force ghat exists between atoms in a molecule
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Ionic bond
A bond between oppositely charged ions. The ions are formed from atoms by transfer if one or more electrons
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Covalent bond
A bond formed between two or more atoms by a sharing of electrons
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Metallic bond
Bonding, usually in solid metals, in which the bonding electrons are relatively free to more throughout the three-dimensional structure
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Lewis symbol
(Electron dot symbol) the chemic symbol for an element, with a dot for each valence electron
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Octet rule
A rule stating that bonded atoms tend to possess or share a total of eight valence she'll electrons
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Lattice energy
The energy required to separate completely the ions in an ionic solid
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Born-haber cycle
A thermodynamic cycle based on hesss las that relates the lattice energy of an ionic substance go it's enthalpy of formation and to other measurable quantities
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Lewis structure
A representation of covalent bonding in a molecule that js drawn using lewis symbols. Shared electron pairs are shown as lines Nd unshared electron pairs are shown Pairs of dots
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️Single bond
A covalent bond involving one electron pair
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Double bond
A covalent bind involving two electron pairs
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Triple bind
A covalent bond involving thee electron pairs
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Bond polarity
A measure of the degree to which the electrons are shared unequally between two atoms in a chemical bond
218
Non polar covalent bond
A covalent bond in which the electrons are shared equally
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Polar covalent bond
A covalent bond in which the electrons are not shared equally
220
Electronegativity
A measure of the ability of an atom that is bonded to another atom to attract electrons to itself
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Polar molecule
A molecule that possesses a nonzero dipole moment
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Dipole
A molecule with one end having a partial negative change and the other snd having a partial positive charge, a polar molecule
223
Dipole moment
A measure of the separation and magnitude of the positive and negative charges in polar molecules
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Formal charge
the number of valence electrons in an isolated atom minus the number of electrons assigned to the atom in the lewis structure
225
Resonance structure
Individual lewis structure in cases where two or more lewis structures are equally good descriptions of a single molecule. The resonance structures in such an instance are averaged to give a more accurate description of the real molecule
226
Bond enthalpy
The enthalpy change, required to break a particular bond when the substance is in the gas phase
