Chemistry
Order by
201 terms
Terms | Definitions |
|---|---|
 Chemistry | the study of matter and the changes that it undergoes |
| Mass | a measure of the amount of matter |
| Model | a visual, verbal, and/or mathematical explanation of data collected from many experiments |
| - Qualitative data | information describing color, odor, shape, or some other physical characteristic |
| - Quantitative data | numerical information describing how much, how little, how big, how tall, how fast, etc. |
| - Weight | a measure if an amount of matter and also can effect of Earth's gravitational pull on that matter |
| - Accuracy | refers to how close a measured value is to an accepted value |
| - Density | a ratio that compares the mass to its volume |
| - Derived unit | a unit defined by a combination of base units |
| - Dimensional analysis | a problem-solving method that focuses on the units that are used to describe matter |
| - Kelvin | the SI base unit of temperature |
| - Kilogram | the SI base unit for mass; about 2.2 pounds |
| - Liter | the metric unit for volume equal to one cubic decimeter |
| - Meter | the SI base unit for length |
| - Percent error | the ratio of an error to an accepted value |
| - Precision | refers to how close a series of measurements are to one another; precise measurements show how little variation over a series of trials but may not be accurate |
| - Scientific Notation | expresses numbers as a multiple of two factors - a number between 1 and 10, and ten raised to a power, or exponent |
| - Significant figure | the number of all known digits reported in measurements plus one estimated digit |
| - Allotropes | forms of an element with different structures and properties when they are in the same state - solid, liquid, or gas |
| - Atom | the smallest particle of an element that retains all the properties of that element; is electrically neutral, spherically shaped, and composed of electrons, protons, and neutrons |
| - Chemical change | a process involving one or more substances changing into new substances; also called a chemical reaction |
| - Chemical properties | the ability or inability of a substance to combine with or change into one or more new substances |
| - Compounds | a chemical combination of two or more different elements; can be broken down into simpler substances by chemical means and has properties different from those of its component elements |
| - Distillation | a technique that can be used to physically separate most homogeneous mixtures based on the differences in the boiling points of the substances involved |
| - Element | a pure substance that cannot be broken down into simpler substances by physical or chemical means |
| - Extensive properties | a physical property, such as mass, length, and volume, that is dependent upon the amount of substance present |
| - Filtration | a technique that uses a porous barrier to separate a solid from a liquid |
| - Gas | a form of matter that flows to conform to the shape of its container, fills the container's entire volume, and is easily compressed |
| - Heterogeneous mixture | one that does not have a uniform composition an din which the individual substances remain distinct |
| - Homogeneous mixture | one that has a uniform composition throughout and always has a single phase; also called a solution |
| - Intensive properties | a physical property that remains the same no matter how much of a substance is present |
| - Law of Conservation of Mass | states that mass is neither created nor destroyed during a chemical reaction but is conserved |
| - Law of Definite Proportions | states that, regardless of the amount, a compound is always composed of the same elements in the same proportion by mass |
| - Law of Multiple Proportions | states that when different compounds are formed by the combination of the same elements, different masses of one element combine with the same mass of the other element in a ratio of small whole numbers |
| - Liquid | a form of matter that flows, has constant volume, and takes the shape of its container |
| - Mixture | a physical blend of two more pure substances in any proportion in which each substance retains its individual properties; can be separated by physical means |
| - Percent by Mass | a percentage determined by the ratio of the mass of each element to the total mass of the compound |
| - Periodic Table | a chart that organizes all known elements into a grid of horizontal rows (periods) and vertical columns (groups or families) arranged by increasing atomic number |
| - Physical change | a type of change that alters the physical properties of a substance but does not change its composition |
| - Physical property | a characteristic of matter that can be observed or measured without changing the sample's composition - for example, density, color, taste, hardness, melting point |
| - Solid | a form of matter that has its own definite shape and volume, is incompressible, and expands only slightly when heated |
| - Solution | a uniform mixture that may contain solids, liquids, or gases; also called a homogeneous mixture |
| - States of Matter | the physical forms in which all matter naturally exists on Earth |
| - Substance | a form of matter that has a uniform and unchanging composition; also known as a pure substance |
| - Vapor | gaseous state of a substance that is a liquid or a solid at room temperature |
| - Avogadro's number | the number 6.02 X 10^23 which is the number of representative particles in a mole |
| - Hydrate | a compound that has a specific number of water molecules bound to its atoms |
| - Mole | the SI base unit used to measure the amount of a substance, abbreviated mol; one mole is the amount of a pure substance that contains 6.02 X 10^23 representative particles |
| - Molecular formula | a formula that specifies that actual number of atoms of each element in one molecule or formula unit of the substance |
| - Percent composition | the percent by mass of each element in a compound |
| - Alpha particle | a particle with two protons and two neutrons, with a 2+ charge; is equivalent to a helium-4 nucleus, emitted during radioactive decay ( ) |
| - Atomic Mass | the weighted average mass of the isotopes of that element |
| - Atomic Mass unit | (amu) one-twelfth the mass of a carbon-12 atom |
| - Atomic Number | the number of protons in an atom |
| - Beta particle | a high-speed electron with a 1- charge is emitted during radioactive decay |
| - Cathode ray | a ray of radiation that originates from the cathode and travels to the anode of a cathode ray tube |
| - Dalton's Atomic Theory | a theory proposed by John Dalton in 1808, based on numerous scientific experiments, that marked the beginning of the development of modern atomic theory |
| - Electron | a negatively charged, fast-moving particle with an extremely small mass that is found in all forms of matter and moves through the empty space surrounding an atom's nucleus |
| - Gamma ray | high-energy radiation that has no electrical charge and no mass, is not deflected by electric or magnetic fields, usually accompanies alpha and beta radiation, and accounts for most of the energy lost during radioactive decay |
| - Isotope | atoms of the same element with the same number of protons but different numbers of neutrons |
| - Mass number | the number after an element's name, representing the sum of its protons and neutrons |
| - Neutron | a neutral subatomic particle in an atom's nucleus that has a mass nearly equal to that of a proton |
| - Nucleus | the extremely small, positively charged, dense center of an atom that contains positively charged protons, neutral neutrons, and is surrounded by empty space through which one or more negatively charged electrons move |
| - Proton | a subatomic particle in an atom's nucleus that has a positive charge of 1+ |
| - Radiation | the rays and particles - alpha and beta particles and gamma rays - that are emitted by radioactive materials |
| - Radioactive decay | a spontaneous process in which unstable nuclei lose energy by emitting radiation |
| - Radioactivity | the process in which some substances spontaneously emit radiation |
| - Amplitude | the height of a wave from the origin to a crest, or from the origin to a trough |
| - Atomic Emission Spectrum | a set of frequencies of electromagnetic waves given off by atoms of an element; consists of a series of fine lines of individual colors |
| - Atomic orbital | a 3D region around the nucleus of an atom that describes an electron's probable location |
| - Aufbau Principle | states that each element occupies the lowest energy orbital available |
| - de Broglie Equation | predicts that all moving particles have wave characteristics and relates each particle's wavelength to its frequency, its mass, and Planck's constant |
| - Electromagnetic spectrum | includes all forms of electromagnetic radiation, with the only differences in the types of radiation being their frequencies and wavelengths |
| - Energy sublevel | the energy levels contained within a principal energy level |
| - Electron configuration | the arrangement of electrons in an atom, which is prescribed by three rules - the Aufbau principle, the Pauli exclusion principle and Hund's rule |
| - Frequency | the number of waves that pass a given point per second |
| - Ground state | the lowest allowable energy state of an atom |
| - Heisenberg Uncertainty Principle | states that it is not possible to know precisely both the velocity and the position of a particle at the same time |
| - Hund's rule | states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbital's |
| - Pauli Exclusion Principle | states that a maximum of two electrons may occupy a single atomic orbital, but only if the electrons have opposite spins |
| - Photoelectric effect | a phenomenon in which photoelectrons are emitted from a metal's surface when light of a certain frequency shines on the surface |
| - Photon | a particle of electromagnetic radiation with no mass that carries a quantum of energy |
| - Planck's constant | h, which has a value of 6.6263 X 10^-34 J-s, where J is the symbol for joule |
| - Principle energy level | the major energy level of an atom |
| - Principal Quantum Number | n, which the quantum mechanical model assigns to indicate the relative sizes and energies of atomic orbital's |
| - Quantum | the minimum amount of energy that can be gained or lost by an atom |
| - Quantum mechanical model of the atom | an atomic model in which electrons are treated as waves; also called the wave mechanical model of the atom |
| - Valence electrons | the electrons in an atom's outermost orbital's; determines the chemical properties of an atom |
| - Wavelength | the shortest distance between equivalent points on a continuous wave; usually expressed in meters, centimeters, or nanometers |
| - Actinides | in the periodic table, the f-block elements from period 7 that follow the element actinium |
| - Alkali Metals | group 1A elements, except for hydrogen, that are on the left side of the modern periodic table |
| - Alkaline Earth Metals | group 2A elements in the modern periodic table |
| - Group | a vertical column of elements in the period table; also called a family |
| - Halogen | a highly reactive group 7A element |
| - Inner Transition Metal | a type of group B element that is contained in the f-block of the periodic table and is characterized by a filled outermost s orbital, and filled or partially filled 4f and 5f orbital's |
| - Ion | an atom or bonded group of atoms with a positive or negative charge |
| - Ionization energy | the energy required to remove an electron from a gaseous atom; generally increases in moving from left-to-right across a period and decreases in moving down a group |
| - Metal | an element that is solid at room temperature, a good conductor of heat and electricity, and generally is shiny; most metals are ductile and malleable |
| - Metalloid | an element, such as Silicon or Germanium, that has physical and chemical properties of both metals and nonmetals |
| - Noble Gas | an extremely unreactive group 8A element |
| - Nonmetal | elements that are generally gases or dull, brittle solids that are poor conductors of heat and electricity |
| - Octet rule | states that atoms lose, gain, or share electrons in order to acquire a full set of eight valence electrons |
| - Period | a horizontal row of elements on the modern periodic table |
| - Periodic law | states that when the elements are arranged by increasing atomic number, there is a periodic repetition of their chemical and physical properties |
| - Representative elements | groups of elements in the modern periodic table that are designated with an A and posses a wide range of chemical and physical properties |
| - Transition element | groups of elements in the modern periodic table that are designated with a B and are further divided into transition metals and inner transition metals |
| - Transition metals | a type of group B element that is contained in the d-block of the periodic table and, with some exceptions, is characterized by a filled outermost s orbital of energy level n, and filled or partially filled d orbital's of energy level n - 1 |
| - Anion | an ion that has a negative charge; forms when valence electrons are added to the outer energy level, giving the ion a stable electron configuration |
| - Cation | an ion that has a positive charge; forms when valence electrons are removed, giving the ion a stable electron configuration |
| - Chemical bond | the force that holds two atoms together, may form by the attraction of a positive ion for a negative ion or by the attraction of a positive nucleus for negative electrons |
| - Empirical formula | a formula that shows the smallest whole-number mole ratio of the element of a compound, and may or may not be the same as the actual molecular formula |
| - Ionic bond | the electrostatic force that holds oppositely charged particles together in an ionic compound |
| - Molar mass | the mass in grams of one mole of any pure substance |
| - Monatomic ion | an ion formed from only one atom |
| - Polyatomic ion | an ion made up of two or more atoms bonded together that acts as a single unit with a net charge |
| covalent bonding | attractive force produced as a result of shared electrons |
| molecule | formed when two or more atoms bond covalently |
| sigma bond/single covalent bond | orbitals overlap end to end, concentrating the electrons in a bonding orbital between the two atoms |
| pi bond | forms when parallel p orbitals overlap. always accompanies a sigma bond |
| exothermic | feels hot. occurs if more energy is released when new bonds form than was required to break the original bonds. |
| endothermic | feels cold. occurs when more energy is required to break the original bonds than is released when new bonds form. |
| VSEPR model | used to determine the shape of the molecule. atoms align themselves in a molecule in minimize the repulsive forces of their electron clouds. |
| hybridization | a process where atomic orbitals mix together |
| resonance | when a molecule or ion has more than one valid Lewis Structure can be drawn |
| polar covalent bonds | determined by difference in electronegativity |
| chemical reaction | the process by which one or more substances are rearranged to form different substances |
| combustion reaction | oxygen gas combines with a substance and release energy in the form of heat and light. commonly produces CO2 and H20. |
| synthesis reaction | reaction with two or more substances react to produce a single product (A + B = C) |
| decomposition (dissociation) reaction | reaction in which a single compound breaks down into more elements or new compounds (C = B + A) |
| single replacement reaction | reaction in which the atoms of one element replaces the atoms of another element in a compound (A + BC = AC + B) |
| double replacement reaction | exchange of ions between two compounds (AB + CD = AD + BC) |
| spectator ions | ions in a solution that do not participate in a chemical reaction |
| ionic equation | reactions that form precipitates |
| net ionic equation | chemical equation for a reaction which lists on those species participating in the reaction |
| stoichiometry | the study of quantitative relationships between the amounts of reactant used and the amounts of products formed by a chemical reaction |
| excess reactant | reactant that will not be used up in a reaction that goes to completion |
| limiting reactant | reactant that is consumed first in a reaction that goes to completion |
| empirical formula | the simplest whole number ratio of atoms of each element present in a compound |
| molar mass | its mass per amount of substance (kg/mole) |
| kinetic-molecular theory | describes the behavior of gases in terms of particles in motion |
| temperature | a measure of the average kinetic energy of the particles in a sample of matter |
| diffusion | the term used to describe the movement of one material through another |
| Graham's law of effusion | states that the rate of effusion for a gas is inversely proportional to the square root of its molar mass. applies to rates of diffusion. (rate A / rateB) = (molar mass B / molar mass A) ^1/2 |
| pressure | force per unit area (SI unit: pascal) |
| barometer | an instrument used to measure atmospheric pressure |
| Dalton's law of partial pressures | states that the total pressure of a mixture of gases is equal to the sum of the pressure of all the gases in the mixture. P(total) = P(1) + P(2) + P(3) + ...P(n) |
| dispersion forces | weak forces that result from temporary shifts in the density of electrons in electron clouds. also known as London forces |
| dipole-dipole forces | attractions between oppositely charged regions of polar molecules. greater than dispersion forces |
| hydrogen bonds | a dipole-dipole attraction that occurs between molecules containing a hydrogen atom bonded to a small, highly electronegative atom with at least one lone electron pair. STRONGEST |
| viscosity | a measure of the resistance of a liquid to flow. determined by the type of intermolecular forces involved, the shape of particles, and the temperature |
| surface tension | a measure of the inward pull by particles in the interior |
| surfactants | compounds that lower the surface tension of water. ex: soap |
| crystalline solids | a solid whose atoms, ions, or molecules are arranged in an orderly, geometric, 3D structure. |
| unit cell | the smallest arrangment of connected points that can be repeated in three directions to form the lattice |
| amorphous solid | a solid in which the particles are not arranged in a regular, repeating pattern |
| melting point | the temperature at which the forces holding its crystal lattice together are broken and it becomes a liquid |
| vaporization | the process by which a liquid changes to a gas or vapor |
| evaporation | when vaporization occurs only at the surface of a liquid. molecules require energy not heat to evaporate. |
| vapor pressure | the pressure exerted by a vapor over a liquid |
| boiling point | the temperature at which the vapor pressure of a liquid equals the external or atmospheric pressure. at this temp all the liquid molecules have enough energy to vaporize |
| sublimation | the process by which a solid changes directly to a gas without first becoming a liquid |
| condensation | the process by which a gas or vapor becomes a liquid |
| deposition | the process by which a substance changes from a gas or capor to a solid without first becoming a liquid |
| freezing point | the temperature at which a liquid is converted into a crystalline solid |
| phase diagram | a graph of pressure versus temperature that shows in which phase a substance exists under different conditions of temperature and pressure |
| triple point | the point on a phase diagram that represents the temperature and pressure at which three phases of a substance can coexist |
| Boyle's Law | states that the volume of a given amount of gas held at a constant temperature varies inversely with the pressure. P(1)V(1) = P(2)V(2) |
| Charles's Law | states that the volume of a given mass of gas is directly proportional to its kelvin temperature at constant pressure. V(1)/T(1) = V(2)/T(2) |
| Gay Lussac's Law | states that the pressure of a given mass of gas varies directly with the kelvin temperature when the volume remains constant. P(1)/T(1) = P(2)/T(2) |
| Combined Gas Law | states the relationship among pressure, temperature, and volume of a fixed amount of gas. P(1)V(1) / T(1) = P(2)V(2) / T(2) |
| Avogadro's Principle | states that equal volumes of gases at the same temperature and pressure contain equal numbers of particles |
| molar volume | (for a gas) the volume that one mole occupies at 0.00 degree C and 1.00 atm pressure. |
| Ideal Gas Law | describes the physical behavior of an ideal gas in terms of the pressure, volume, temperature, and number of moles of gas present. PV = nRT |
| STP | standard temperature (0 degree C/273 K) and pressure (1 atm) |
| soluble | when a substance is able to dissolve in a solvent |
| insoluble | when a substance does not dissolve in a solvent |
| immiscible | used to describe liquids that are insoluble together |
| miscible | used to describe liquids that are soluble in each other |
| solvation | the process of surrounding solute particles with solvent particles to form a solution |
| hydration | solvation in water |
| heat of solution | the overall energy change that occurs during the solution formation process |
| solubility | the maximum amount of solute that will dissolve in a given amount of solvent at a specified temp and pressure |
| saturated solution | a solution that contains the maximum amount of dissolved solute for a given amount of solvent |
| unsaturated solution | a solution where more solute can still be dissolved |
| supersaturated solution | a solution that contains more dissolved solute than a saturated solution at the same temp |
| Henry's Law | states that at a given temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid. S(1) / P(1) = S(2) / P(2) |
| concentration | a measure of how much solute is dissolved in a specific amount of solvent or solution |
| percent by mass (formula) | [(mass of solute) / (mass of solution)] X100 |
| percent by volume (formula) | [(volume of solute) / (volume of solution)] X100 |
| molarity | the number of moles of solute dissolved per liter of solution. formula: M = (moles of solute / liters of solution) |
| molality | the ratio of the number of moles of solute dissolved in one kilogram of solvent. formula: m = (moles of solute / kilogram of solvent) |
| mole fraction | the ratio of the number of moles of solute in solution to the total number of moles of solute and solvent |
| colligative properties | physical properties of solutions that are affected by the number of particles but not the identity of dissolved solute particles |
| freezing point depression | the difference in temperature between a solution's freezing point and the freezing point of its pure solvent |
| vapor pressure lowering | is due to the number of solute particles in solution and is a colligative property of solutions |
| boiling point elevation | the temperature difference between a solution's boiling point and a pure solvent's boiling point |
| osmotic pressure | the amount of additional pressure caused by the water molecules that moved into the solution |
| suspension | a mixture containing particles that settle out if left undisturbed |
| colloid | a heterogeneous mixture of intermediate sized particles |
| Brownian motion | the erratic movement of colloid particles |
| tyndall effect | dispersed colloid particles that are large enough to scatter light |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.