Question | Answer |
Analytical Chemistry | The area of chemistry that focuses on the composition of matter |
Applied Chemistry | research that is direct toward a practical goal or application |
Biochemistry | the areas of chemistry that focuses on processes that take place in organisms |
Biotechnology | the field that applies science to the production of biological products or processes |
Chemistry | the study of the composition of matter and the changes that matter undergoes. |
Experiment | -a repeatable procedure that is used to test a hypothesis |
Hypothesis | a proposed explanation for an observation |
Inorganic chemistry | the study of substances that in general do not contain carbon |
Macroscopic | describes the world of objects that are large enough to see with the unaided eye |
Matter | anything that has mass and occupies space |
Microscope | describes the world of objects that can be seen only under magnification |
Manipulated variable | the variable that is changed during an experiment; also called independent |
Observation | information obtained through the senses; observation in science involving measurement |
Organic chemistry | the study of compounds containing carbon |
Physical Chemistry | the area of chemistry that deals with the mechanism, the rate and the energy transfer that occurs when matter undergoes change. |
Pollutant | a material found in air, water, or soil that is harmful to humans and other organisms |
Pure Chemistry | The pursuit of chemical knowledge for its own sake |
Responding Variable | the variable that is observed during an experiment; dependent variable |
Scientific Law | a concise statement that summarizes the results of many observations and experiments |
Scientific Method | a logical, systematic approach to the solutions of a scientific problem; steps in the scientific method include making observations, testing hypotheses and developing theories |
Technology | the means by which a society provides its members with those things needed and desired |
Theory | a well tested explanation for a broad set of observations |
Chemical Change | A change that produces matter with a different composition than the original. |
Chemical property | The ability of a substance to undergo a specific chemical change. |
Chemical reaction | A change in which one or more reactants change into one or more products; characterized by the breaking of bonds in reactants and the formation of bonds in products. |
Chemical Symbol | A one |
Compound | a substance that contains two or more elements chemically combined in a fixed proportion. |
Distillation | A process used to separate dissolved solids from a liquid, which is boiled to produce a vapor that is then condensed into a liquid. |
Element | the simplest form of matter that has a unique set of properties; an element cannot be broken down into simpler substances by chemical means. |
Extensive property | A property that depends on the amount of matter in a sample. |
Filtration | A process that separates a solid from the liquid in a heterogeneous mixture. |
Gas | A form of matter that takes the shape and volume of its container; a gas has no definite shape or volume. |
Heterogeneous Mixture | A mixture that is not uniform in composition; components are not evenly distributed throughout the mixture. |
Homogeneous Mixture | A mixture that is uniform in composition; Components are evenly distributed and not easily distinguished. |
Intensive Property | A property that depends on the type of matter in a sample, not the amount of matter. |
Law of Conservation of Mass: In any physical change or chemical reaction mass is conserved; mass can be neither created or destroyed. | |
Liquid | A form of matter that flows, has a fixed volume and a indefinite shape. |
Mass | A measure of the amount of matter that an object contains; the SI base unit of mass is the Kilogram. |
Mixture | A physical blend of two or more substances that are not chemically combined. |
Phase | any part of a sample with uniform composition and properties. |
Physical Change | A change during which some properties change but the composition of the material does not. |
Physical Property | A quality or condition of a substance that can be observed of measured without changing the substances composition. |
Precipitate | A solid that dorms and settles out of a liquid mixture. |
Product | A substance produced in a chemical reaction. |
Reactant | A substance present at the start of a reaction. |
Solid | A form of matter that has definite shape and volume. |
Solution | A homogeneous mixture; consists of solutes dissolved in a solvent. |
Substance | Matter that has uniform and definite composition; either an element or a compound; also called a pure substance. |
Vapor | Describes the gaseous state of a substance that is generally a liquid or a solid at room temperature. |
Volume | A measure of the space occupied by a sample of matter. |
Absolute Zero | The zero point on the Kelvin temperature scale, equivalent to -273.15°C. |
Accepted Value | A quantity used by general agreement of the scientific community. |
Accuracy | The closeness of a measurement to the true value of what is being measured. |
Calorie(cal) | The quantity of heat needed to raise the temperature of 1 g of pure water 1°C. |
Celsius Scale | The temperature scale on which freezing point of water is 0°C and the boiling point of water is 100°C. |
Conversion Factor | a ratio of equivalent measurements used to convert a quantity from one unit to another. |
Density | The ratio of mass of an object to its volume. |
Dimensional Analysis | A technique of problem solving that uses the units that read part of measurements to help solve the problem. |
Energy | The capacity for doing work or producing heat. |
Error | the difference between the accepted value and the experimental value. |
Experimental Value | a quantative value measured during an experiment. |
Gram(g) | a metric mass unit equal to the mass of 1 cm3 of water at 4°C. |
International System of Units(SI) | the revised version of the metric system adopted by international agreement in 1960 |
Joule(J) | the SI unit of energy; 4.184 J=Calorie |
Kelvin Scale | the temperature scale in which freezing point is 273.15 K and the boiling point is 373.15K; 0K is absolute zero. |
Kilogram(Kg) | the mass of 1 L of water at 4°C; it is the base unit of mass in SI. |
Liter(L) | the volume of a cube measuring 10cm on each edge or 1000cm3; it is the common unprefixed unit of volume in the metric system. |
Measurement | a quantivtive description that includes both a number and a unit. |
Meter(m) | the base unit of length in SI |
Percent error | the percent that a measured value differs from the accepted value. |
Precision | describes the closeness or reproducibility of a set of measurements taken under the same conditions. |
Scientific Notation | an expression numbers in the form m X 10n where m is equal to or greater than one and less than 10, and n is an integer. |
Significant Figures | all the digits that can be known precisely in a measurements plus a last estimated digit. |
Temperature | a measure of the average kinetic energy of particles in matter; temperature determines the direction of heat transfer. |
Weight | a force that measure the pull of gravity one given mass. |
Atom | the smallest particle of an element that retains its identity in a chemical reaction |
Atomic Mass | the weighted average of the masses of the isotopes of an element |
Atomic Mass Units(amu) | a unit of mass equal to one |
Atomic Number | the number of protons in the nucleus of an atom of an element |
Cathode Ray | the electrode at which reduction occurs |
Dalton's Atomic Theory | the first theory to relate chemical changes to events at the atomic level |
Electron | a negatively charged subatomic particle |
Group | a vertical column of elements in the periodic table, the constituent elements of a group have similar chemical and physical properties |
Isotopes | atoms of the same element that have the same atomic number but different atomic masses due to a difference in number neutrons |
Mass Number | the total amount of protons and neutrons in the nuclear of an atom. |
Neutron | subatomic particle that has no charge and a mass of 1 amu; found in the nucleus of an atom |
Nucleus | the tiny dense central portion of an atom; composed of protons and neutrons |
Period | horizontal row of elements in the periodic table |
Periodic Table | an arrangement of elements in which the elements are separated into groups based on a set of repeating properties |
Proton | a positively charged subatomic particle found in the nucleus of an atom |
Amplitude | the height of a wave's crest |
Atomic Emission Spectrum | the pattern formed when light passes through a prism or diffraction grating to separate it into different frequencies of light it contains. |
Atomic Orbital | A mathematical expression describing the probability of finding an electron at various locations; usually represented by the region of space around the nucleus where there is a high probably of finding an electron |
Aufbau Principle | the rule that electrons occupy the orbital's of lowest energy first |
Electromagnetic Radiation | energy waves that travel in a vacuum at a speed of 2.998 X 108 m/s; includes radio, radar, micro, infrared, visible, ultraviolet, x |
Electron Configurations | the arrangement of electrons of an atom in its ground state into various orbital's around the nuclei of atoms |
Energy Levels | the specific energies an electron in an atom or other system can have |
Frequency | the number of wave cycles that pass a given point per unit of time; frequency and wavelength are inversely proportional to each other. |
Ground State | The lowest possible energy of an electron described by quantum mechanics. |
Heisenberg Uncertainty Principle | it is impossible to know exactly both the velocity and the position of a particle at the same time |
Hertz | the unit of frequency equal to one cycle per a second |
Hund's Rule | electrons occupy orbital's of the same energy in a way that makes the number of electrons with the same spin direction as large as possible |
Pauli Exclusion Principle | an atomic orbital may describe at most two electrons each with opposite spin directions |
Photons | a quantum of light; a discrete bundle of electromagnetic energy that interacts with matter similarly to particles. |
Quantum | the amount of energy needed to move an electron from one energy level to another |
Quantum Mechanical Model | the modern description, primarily mathematical of the behavior of electrons in atoms. |
Spectrum | wavelengths of visible light that are separated when a beam of light passes through a prism; range of wavelengths of EM radiation |
Wavelength | the distance between adjacent crests in a wave |
Alkali Metals | Any metal in group 1A of the periodic table |
Alkaline Earth Metals | any metal in group 2A of the periodic table |
Anion | Any atom or group of atoms with a negative charge |
Atomic Radius | one |
Cation | any atom or group of atoms with a positive charge |
Electronegativity | the ability of an atom to attract electrons |
Halogens | a nonmetal in group 7A of the periodic table |
Inner Transition Metal | an element in the lanthanide or actinide series; the highest occupied s sublevel and nearby f sublevel of its atoms generally contain electrons; also called inner transition elements |
Ion | an atom or group of atoms that has a positive or negative charge |
Ionization Energy | the energy required to remove an electron from an atom in its gaseous state |
Metalloids | an element that tends to have properties that are similar to those of metals and nonmetals |
Metals | one of a class of elements that are good conductors of heat and electric current; metals tend to be ductile, malleable and shiny |
Noble Gases | An element in group 8A of the periodic table; the s and p sublevels of the highest occupied energy level are filled |
Nonmetals | an element that tends to be a poor conductor of heat and electric current; nonmetals generally have properties opposite to those of metals |
Periodic Law | when the element are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties |
Representative Elements | an element in an "A" group in the periodic table. As a group of these elements display a wide range of chemical properties and physical properties. In their atoms, the s and p sublevels in the highest occupied energy level are partially full |
Transition Metal | one of the group B elements in which the highest occupied s sublevel and a nearby d sublevel generally contain electrons. |
Alloys | a mixture composed of two or more elements, at least one of which is metal |
Chemical Formula | An expression that indicates the number and type of atoms present in the smallest representative units of a substance |
Coordination Number | the number of ions of opposite chare that surround each ion in a crystal |
Electron Dot Structure | A notation that depicts valence electrons as dots around the atomic symbol of the element; the symbol represents the inner electrons and atomic nucleus; also called Lewis dot structure |
Formula Unit | the lowest whole-number ratio of ions in the ionic compound; in magnesium chloride the ratio of magnesium ions to chloride ions is 1 |
Halide Ion | a negative ion formed when a halogen atom gains an electron |
Ionic Bond | the electrostatic attraction that binds oppositely charged ions together |
Ionic Compounds | a compound composed of positive and negative ions |
Metallic Bonds | the force of attraction that holds metal together; it consists of the attraction of free-floating valence electrons for positively charged metal ions |
Octet Rule | atoms react by gaining or losing electrons so as to acquire the stable electron structure of a Nobel gas, usually eight valence electrons |
Valence Electron | an electron in the highest occupied energy level of an atom. |
Bond Dissociation Energy | the energy required to break the bond between two covalently bonded atoms; this value is usually expressed in kJ per mol of a substance |
Bonding Orbital | a molecular orbital that can be occupied by two electrons of a covalent bond |
Covalent Bond | a bond formed by the sharing of electrons between atoms |
Coordinate Covalent Bond | a covalent bond in which one atom contributes both bonding electrons |
Diatomic Molecule | a molecule consisting of two atoms |
Dipole | a molecule that has two poles or regions with opposite charges |
Dipole Interactions | intermolecular forces resulting from the attraction of oppositely charged regions of polar molecules |
Dispersion Forces | attractions between molecules caused by the electron motion on one molecule affecting the electron motion on the other through electrical forces; these are the weakest interactions between molecules |
Double Covalent Bond | a bond in which two atoms share two pairs of electrons |
Hybridization | the mixing of several atomic orbital's to form the same total number of equivalent hybrid orbital's |
Hydrogen Bonds | attractive forces in which a hydrogen covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom |
Molecular Compound | a compound that is composed of molecules |
Molecular Formula | chemical formula of a molecular compound that shows the kinds and numbers of atoms present in a molecule of a compound |
Molecular Orbital | an orbital that applies to the entire molecule |
Molecule | a neutral group of atoms joined together by covalent bonds |
Network Solids | a solid in which all of the atoms are covalently bonded to each other |
Non | polar Covalent bond |
Pi Bond | a covalent bond in which the bonding electrons are most likely to be found in sausage |
Polar Bond | a covalent bond between atoms in which the electrons are shared unequally |
Polar Covalent Bond | aka polar bond |
Polar Molecule | a molecule in which one side of the molecule is slightly negative and the opposite side is slightly positive |
Polyatomic Ion | a tightly bond group of atoms that behaves as a unit and has a positive or negative charge |
Resonance Structure | one of the two or more equally valid electron dot structures of a molecule or polyatomic ion |
Sigma Bond | a bond formed when two atomic orbital combine to form a molecular orbital that is symmetrical around the axis connection the two atomic nuclei |
Single Covalent Bond | a bond formed when two atoms share a pair of electrons |
Structural Formula | a chemical formula that shows the arrangement of atoms in a molecule or polyatomic ion; each dash between a pair of atoms indicates a pair of shared electrons |
Tetrahedral Angle | a bond angle of 109.5 that results when a central atom forms four bonds directed toward the center of a regular tetrahedron |
Triple Covalent Bond | a covalent bond in which three pairs of electrons are shared by two atoms |
Unshared Pair | a pair of valence electrons that is no shared between atoms aka lone pair |
Van der Waals Forces | the two weakest intermolecular attractions |
VSEPR Theory | valence |
Acid | a compound that produces hydrogen ions in solution |
Base | a compound that produces hydroxide ions in solution |
Binary Compound | a compound composed of two elements |
Law of Definite Proportions | in samples of any chemical compound the masses of the elements are always in the same proportion |
Law of Multiple Proportions | whenever two elements form more than one compound the different masses of one element combine with the same mass of the other elements to form simple whole umber ratios |
Monatomic Ion | a single atom with a positive and negative charge resulting from the loss or gain of one or more valence electrons |
Polyatomic Ion | a tightly bound group of atoms that behaves as a unit and has a positive or negative charge |
Avogadro's hypothesis | equal volumes of gases at the same temperature and pressure contains equal numbers of particles |
Avogadro's Number | the number of representatives particles contained in one mole of a substance; equal to 6.02 X 10 23particles |
Empirical Formula | a formula with the lowest whole number ratio of elements in a compound |
Molar Mass | a term used to refer to the mass of a mole of any substance |
Molar Volume | the column occupied by one mole of gas at STP (22.4L) |
Mole(mol) | the amount of substance that contains 6.02 X 10 23 representative particles of that substance. |
Percent Composition | the percent by mass of each element in a compound |
Representative Particle | the smallest unit into which a substance ca be broken down without a change in composition usually atoms molecules or ions. |
Standard Temperature and Pressure(STP) | the conditions under which the volume of a gas is usually measured; 0 degrees Celsius and 101.3kPa or 1 atmosphere(atm) |
Activity Series | a list of elements in order of decreasing activity; the activity series of halogens is Fl, Cl, Br, I |
Balanced Equation | a chemical equation in which mass is conserved; each side of the equation has the same number of atoms of each element |
Catalyst | A substance that speeds up the rate of reaction by lowering the activation energy barrier; the catalysts is not used up in the reaction. |
Chemical Equation | an expression representing a chemical reaction; the formulas of the reactants (L) are connected by an arrow with the formulas for the products(r.) |
Coefficients | a small whole number that appears in front of a formula to a balanced equation |
Combination Reaction | or synthesis; is a chemical change in which two or more substances react to form a single new substance |
Combustion Reaction | a chemical change in which an element or a compound reacts with oxygen, often producing energy in the form of heat and light. |
Complete Ionic Equation | an equation that shows dissolved ionic compounds as dissociated free ions |
Decomposition Reaction | a chemical change in which a single compound is broken down into two or more simpler products |
Double Replacement Reaction | a chemical change that involves an exchange of positive ions between compounds |
Net Ionic Equation | an equation for a reaction in solution showing only those particles that are directly involved in the chemical change |
Single Replacement Reaction | a chemical change in which one element replaces a second element in a compound; also called displacement reaction |
Skeleton Equation | a chemical equation that does not indicate the relative amounts of reactants and products |
Spectator Ion | an ion that is not directly involved in a chemical reaction; an ion that does not change oxidation number or composition during reaction. |
Actual Yield | the amount of product that forms when a reaction is carried out in the laboratory |
Excess Reagent | a reagent present in a quantity that is more than sufficient to react with a limiting; any reactant that remains after the limiting reagent is used up in a chemical reaction |
Limiting Reagent | any reagent that is used up first in a chemical reaction; it determines the amount of product that can be formed in the reaction |
Mole Ratio | a conversion factor derived from the coefficients of a balanced chemical equation interpreted in terms of moles |
Percent Yield | the ratio of the actual yield to the theoretical yield for a chemical reaction expressed as a percentage; a measure of the efficiency of a reaction |
Stoichiometry | the portion of chemistry dealing with numerical relationships in chemical reaction; the calculation of quantities of substances involved in chemical equations. |
Allotrope | one of two or more different molecular forms of an element in the same physical state; graphite and diamond |
Amorphous Solid | describes a solid that lacks an ordered internal structure; denotes a random arrangement of atoms |
Atmospheric Pressure | the pressure exerted by atoms and molecules in the atmosphere surrounding earth, resulting from collisions of these particles with objects. |
Barometer | an instrument used to measure atmospheric pressure |
Boiling Point | the temperature at which vapor pressure of a liquid is just equal to the external pressure on the liquid (BP) |
Crystal | a solid in which the atoms, ion or molecules are arranged in an orderly, repeating three dimensional pattern called a crystal lattice |
Evaporation | vaporization that occurs at the surface of a liquid that is not boiling |
Gas Pressure | results from the force exerted by a gas per unit surface area of an object; due to collisions of gas particles with the object |
Glass | transparent fusion product of inorganic materials that have cooled to a rigid state without crystallizing |
Kinetic Energy | the energy an object has because of its motion |
Kinetic Theory | a theory explaining the states of matter, based on the concept that all matter consists of tiny particles that are in constant motion |
Melting Point | the temperature at which a substance changes from a solid to a liquid; the melting point of water is 0 degrees Celsius (MP) |
Normal Boiling Point | the boiling point of a liquid at a pressure of 101.3kPa or 1 atm |
Pascal | the SI unit of pressure |
Phase Diagram | a graph showing the conditions at which a substance exists as a solid, liquid or vapor |
Standard Atmosphere(atm) | a unit of pressure; it is the pressure required to support 760 mm of mercury in a mercury barometer at 25 degrees Celsius |
Sublimation | the process in which a solid changes to a gas or vapor without passing through the liquid state |
Triple Point | the point on a phase diagram that represents the only set of conditions at which all three phases exist in equilibrium with one another |
Unit Cell | the smallest group of particles within a crystal that retains the geometric shape of the crystal |
Vacuum | a space where no particles of matter exist |
Vaporization | the conversion of liquid to a gas or vapor |
Vapor Pressure | a measure of the force exerted by a gas above a liquid in a sealed container; a dynamic equilibrium exists between the vapor and the liquid |
Boyle's Law | for a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure |
Charles's Law | the volume of a fixed mass of gas is directly proportional to its Kelvin temperature if the pressure is kept constant |
Combined Gas Law | the law that describes the relationship among the pressure, temperature, and volume of an enclosed gas |
Compressibility | a measure of how much the volume of matter decreases under pressure |
Dalton's Law Of Partial Pressures | at constant volume and temperature the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases |
Diffusion | the tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout. |
Effusion | the process that occurs when a gas escapes through a tiny hole in its container |
Gay-Lussac's Law | the pressure of a gas is directly proportional to the Kelvin temperature if the volume is constant |
Graham's Law of Effusion | the rate of effusion of a gas inversely proportional to the square root of its molar mass; this relationship is also true for diffusion of gases |
Ideal Gas Constant | the constant in the ideal gas law with the symbol R that has the value 8.31 (L*kPa)/(K*mol) |
Ideal Gas Law | the relationship PV =nRT which describes the behavior of an ideal gas |
Partial Pressure | the contribution each gas in a mixture of gases makes to the total pressure |
Aqueous Solution | water that contains dissolved substances |
Browian Motion | the chaotic movement of colloidal particles, caused by collision with particles of the solvent in which they are dispersed |
Colloid | a mixture whose particles are intermediate in size between those of a suspension and a solute solution |
Electrolyte | a compound that conducts an electric current when it is in an aqueous solution or in the molten state; all ionic compound are electrolytes but most covalent compounds are not. |
Emulsion | the colloidal dispersion of one liquid in another |
Hydrate | a compound that has a specific number of water molecules bound to each formula unit |
Nonelectrolyte | a compound that does not conduct an electric current in aqueous solution or in the molten state |
Solute | dissolved particles in a solution |
Solvation | a process that occurs when an ionic solute dissolves; in a solution, solvent molecules surround the positive and negative ions |
Solvent | the dissolving medium in a solution |
Strong Electrolyte | a solution in which a large portion of the solute exists as ions |
Surfactant | any substance that that interferes with the hydrogen bonding between water molecules and thereby reduces surface tension; soap and detergents are surfactants |
Suspension | a mixture from which some of the particles settle out slowly upon standing |
Surface Tension | an inward force that tends to minimize the surface area of a liquid; it causes the surface to behave as if it were a thin skin |
Tyndall Effect | scattering of light particles in a colloid or suspension, which causes a beam of light to become visible |
Weak Electrolyte | a solution that conducts electricity poorly because only a fraction of the solute exists as ions |
Boiling Point Elevation | the difference in temperature between the boiling point of a solution and the boiling point of a pure solvent |
Concentrated Solution | a solution containing a large amount of solute |
Concentration | a measurement of the amount of a solute that is dissolved in a given quantity of solvent; usually expressed in mol/L |
Colligative Property | a property of a solution that depends solely upon the number of solute particles, and not upon their identities; boiling point elevation, freezing point depression and vapor pressure lowering are colligative |
Dilute Solution | a solution that contains a small amount of solute |
Freezing Point Depression | the difference I temperature between the freezing point of a solution and the freezing point of the pure solvent |
Henry's Law | at a given temperature the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid |
Immiscible | describes liquids that are insoluble in one another; oil and water |
Miscible | describes liquids that dissolve one another in all proportions |
Molal Freezing Point depression Constant | Kf, the change in freezing point for a 1 Molal solution of a nonvolatile molecular solute |
Molal Boiling Point Elevation Constant | Kb, the change in boiling point for a 1 Molal solution of a nonvolatile molecular solute |
Molality | (m) the concentration of solute in a solution expressed as the number of moles of solute dissolved in 1 kg or 1000 g of solvent |
Molarity | (M) the concentration of a solute in a solution expressed as the number of moles of solute dissolved in 1L of solution |
Mole Fraction | the ratio of the moles of solute in solution to the total number of moles of both solvent and solute |
Saturated Solution | a solution containing the maximum amount of solute for a given amount of solvent at a constant temperature and pressure; an equilibrium exists between un-dissolved ions and dissolved ions in solution |
Solubility | the amount of a substance that dissolves in a given quantity of solvent at specified conditions of temperature and pressure to produce a saturated solution |
Supersaturated Solution | a solution that contains more solute than it can theoretically hold at a given temperature; excess solute precipitates if a seed crystal is added |
Unsaturated Solution | a solution that contains less solute than a saturated solution at a given temperature and pressure |
Calorimeter | an insulated devise used to measure the absorption or release of heat in chemical or physical processes |
Calorimetry | the precise measurement of heat flow out of a system for chemical or physical processes |
Chemical Potential Energy | energy stored in chemical bonds |
Endothermic Process | a process that absorbs heat from the surrounding |
Enthalpy | (H) the heat content of a system at constant pressure |
Exothermic Process | a process that releases heat to its surroundings |
Heat | (q) energy that transfers from one object to another because of a temperature difference between the objects |
Heat Capacity | the amount of heat needed to increase the temperature of an object exactly 1°C |
Heat of Combustion | the heat of reaction for the complete burning of one mole of a substance |
Heat of Reaction | the enthalpy change for a chemical equation exactly as it is written |
Hess's Law of Heat Summation | if you add two or more Thermochemical equations to give a final equation then you also add the heats of reaction to give the final heat of reaction |
Law of Conservation of Energy | in ay physical change or chemical reaction, mass is conserved; mass can be neither created or destroyed |
Molar Heat of Condensation | ( ∆Hcond) the amount of heat released by one mole of a vapor as it condenses to a liquid at a constant temperature |
Molar Heat of Fusion | (∆Hfus) the amount of heat absorbed by one mole of a solid substance as it melts to a liquid at a constant temperature |
Molar Heat of Solidification | (∆Hsolid) the amount of heat lost by one mole of a liquid as it solidifies at a constant temperature |
Molar Heat of Solution | (∆Hsoln) the enthalpy change caused by the dissolution of one mole of a substance |
Molar Heat of Vaporization | (∆Hvap) the amount of heat absorbed by one mole of a liquid as it vaporizes at a constant temperature |
Specific Heat | the amount of heat needed to increases the temperature of 1 g of a substance 1°C; also called specific heat capacity |
Standard Heat of Formation | (∆Hf0) the change in enthalpy that accompanies the formation of one mole of a compound from its elements with all substances in their standard states at 25°C |
Surroundings | everything in the universe outside of the system |
System | a part of the universe on which you focus your attention |
Thermochemical Equation | a chemical equation that includes the enthalpy change |
Thermochemistry | the study of energy changes that occur during chemical reactions and changes in state |
Activated Complex | an unstable arrangement of atoms that exists momentarily at the peak of the activation-energy barrier; an intermediate or transitional structure formed during the course of a reaction |
Activation Energy | the minimum energy colliding particles must have in order to react |
Chemical Equilibrium | a state of balance in which the rates of the forward and reverse reactions are equal; no net charge in the amount of reactants and products occurs in the chemical system |
Collision Theory | atoms, ions, and molecules can react to form products when they collide, provided that the particles have enough kinetic energy |
Common Ion | an ion that is common to both salts in a solution; in a solution of silver nitrate and silver chloride Ag+ is the common ion |
Common Ion Effect | a decrease in the solubility of an ionic compound caused by the addition of a common ion |
Elementary Reaction | a reaction in which reactants are converted to products in a single step |
Entropy | (s) a measure of the disorder of a system; systems tend to go from a state of order(low) to a state of maximum disorder(high) |
Equilibrium Constant | (Keq) the ratio of product concentrations to react concentrations at equilibrium, with each concentration raised to a power equal to the umber of moles of that substance in the balanced chemical equation |
Equilibrium Position | the relative concentrations of reactants and products of a reaction that has reached equilibrium; indicates whether the reactants or products are favored in the reversible reaction |
First-Order Reaction | a reaction in which the reaction rate is proportional to the concentration of only one reactant |
Free Energy | the energy available to do work |
Gibbs Free Energy Change | ∆G the maximum amount of energy that can be coupled to another process to do useful work |
Inhibitor | a substance that interferes with the action of a catalysts |
Intermediate | a product of one of the steps in a reaction mechanism; it becomes a reactant in the next step |
Law of Disorder | it is natural tendency of systems to move in the direction of maximum chaos or disorder |
Le Chatliers Principle | when stress is applied to a system dynamic equilibrium, the system changes in a way that relieves the stress |
Nonspontaneous Reaction | a reaction that does not favor the formation of products at the specifies conditions |
Rate | describes the speed of change over an interval of time |
Rate Law | an expression relating the rate of reaction to the concentration of reactants |
Reaction Mechanism | a series of elementary reactions that take place during the course of a complex reaction |
Reversible Reaction | a reaction in which the conversion of reactants into products and the conversion of products into reactants occur simultaneously |
Solubility Product Constant | Ksp the equilibrium constant applied to the solubility of electrolytes; it is equal to the product of the concentration of the ions each raised to the power equal to the coefficient of the ion in the dissociation equation |
Specific Rate Constant | a proportionality constant relation the concentration of reactions to the rate of reaction |
Spontaneous Reaction | a reaction that favors the formation of products at the specified conditions; spontaneity depends on enthalpy and entropy changes |
Transition State | a term sometime used to refer to the activated complex |
Acid Dissociation Constant (Ka) | The ratio of the concentration of the dissociated form of an acid to the undissocitated form; stronger acids have larger Ka Values than weaker acids |
Acidic Solution | any solution in which the hydrogen-ion concentration is greater than the hydroxide-ion concentration |
Alkaline Solution | a basic solution |
Amphoteric | a substance that can act as both an acid and a base |
Base Dissociation Constant (Kb) | the ratio of the concentration of the conjugate acid times the concentration of the hydroxide ion to the concentration of conjugate base |
Basic Solution | any solution in which the hydroxide-ion concentration is greater than the hydrogen-ion concentration |
Buffers | a solution in which the pH remains relatively constant when small amounts of acid or base are added; a buffer can be either a solution of a weak acid and the salt of a weak acid or a solution of a weak base with the salt of a weak base |
Buffer Capacity | a measure of the amount of acid or base that may be added to a buffer solution before a significant change in pH occurs |
Conjugate Acid | the particle formed when a base gains a hydrogen-ion; NH4+ is the conjugate acid of the base NH3 |
Conjugate Acid-Base Pair | two substances that are related by the loss or gain of a single hydrogen ion; ammonia (NH3) and the ammonia ion (NH4+) are a conjugate acid-base pair |
Conjugate Base | the particle that remains when an acid has donated a hydrogen ion; OH- is the conjugate base of the acid water |
Diprotic Acid | any acid that contains two ionizable protons (hydrogen ions); sulfuric acid (H2SO4) is a Diprotic acid |
End Point | the point in a titration at which the indicator changes color |
Equivalent Point | the point of titration where the number of moles of hydrogen ions equals the number of moles of hydroxide ions |
Hydronium Ion(H3O+) | the positive ion formed when a water molecule gains a hydrogen ion |
Ion-Product Constant for Water(Kw) | the product of the concentration of hydrogen ions and hydroxide ions in water; it is 1*10-14 at 25 degrees Celsius |
Lewis Acid | any substance that can accept a pair of electrons to form a covalent bond |
Lewis Base | any substance that can donate a pair of electrons to form a covalent bond |
Monoprotic Acid | any acid that contains one ionizable proton (hydrogen ion); nitric acid is a Monoprotic acid |
Neutral Solution | an aqueous solution in which the concentration of hydrogen and hydroxide ions are equal; it has a pH pf 7.0 |
Neutralization Reaction | a reaction in which an acid and a base react in a aqueous solution to produce a salt and water |
pH | a number use to denote the hydrogen-ion concentration or acidity of a solution; it is the negative logarithm of the hydrogen-ion concentration of a solution |
Salt Hydrolysis | a process in which the cations or anions of a dissociated salt accept hydrogen ions from water or donate hydrogen ions to water |
Self-Ionization | a term describing the reaction in which two water molecules react to produce ions |
Standard Solution | a solution of known concentration used in carrying our a titration |
Strong Acid | an acid that is completely (or almost completely) ionized in aqueous solution |
Strong Base | a base that completely dissociates into metal ions and hydroxide ions in aqueous solution |
Titration | process used to determine the concentration of a solution (often an acid or base) in which a solution of known concentration (the standard) is added to a measured amount of the solution of unknown concentration until an indicator signals the end point |
Tripotic Acid | any acid that contains three ionizable protons (hydrogen ions) |
Weak Acid | an acid that is only slightly ionized in aqueous solution |
Weak Base | a base that reacts with water to form the hydroxide ion and the conjugate acid of the base |