General Chemistry – Flashcards

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matter
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anything that has mass and occupies space
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energy
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the capacity to do work or to transfer heat
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kinetic energy
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the energy of motion
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potential energy
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energy an object possesses because of its position, condition, or composition
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exothermic process
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a process that releases energy (heat) into the environment
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endothermic process
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a process that absorbs energy (heat) from the environment
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Law of Conservation of Matter
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there is no observable change in the quantity of matter during a chemical reaction or during a physical change
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scientific (natural) law
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a general statement based on the observed behavior of matter to which no exceptions are known
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Law of Conservation of Energy
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energy cannot be created or destroyed in a chemical reaction or in a physical change. It can only be converted from one form to another.
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Law of Conservation of Energy and Matter
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the combined amount of matter and energy in the universe is fixed (related to Newton's 2nd Law E=mc^2)
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solid
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a state of matter in which substances are rigid and have definite shapes; very difficult to compress
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liquid
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a state of mater in which substances flow and assume the shape of containers up to the volume of the liquid; difficult to compress
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gas
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a state of matter in which substances occupy all parts of containers; easily compressed and expanded
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chemical properties
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characteristics of matter as it undergoes chemical changes; e.g., the rxn that occurs when metallic magnesium combines with gaseous oxygen
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physical properties
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characteristics of matter with no changes in chemical composition; e.g., color, hardness, density, melting point, etc.
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extensive properties
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properties that depend on the amount of material present in the sample; e.g., volume and mass
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intensive properties
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properties that are independent of the amount of material present in the sample; all chemical properties are intensive
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chemical change
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a reaction in which 1) one or more substances are used up (at least partially), 2) one or new substances are formed, and 3) energy is absorbed or released
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physical change
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a change in which a substance changes from one physical state to another, but no substances with different compositions are formed; energy is absorbed or released
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mixture
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a combination of two or more pure substances in which each substance retains its own composition and properties
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heterogeneous mixture
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a mixture that does not have uniform composition and properties throughout
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homogeneous mixture/solution
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a mixture that has uniform composition and properties throughout
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Classification of Matter
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[image]
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characteristics of any mixture
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1) the composition can be varied and 2) each component of the mixture retains its own properties
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substance
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any kind of matter, all specimens of which have the same chemical composition and physical properties
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compound
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a substance that can be decomposed by chemical means into simpler substances, always in the same ratio by mass
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element
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a substance that cannot be decomposed into simpler substances by chemical changes
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Law of Definite Proportions (aka Law of Constant Composition)
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different samples of any pure compound contain the same elements in the same proportions by mass; this corresponds to atoms of these elements in fixed numerical ratios
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mass
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the measure of the quantity of matter a body contains
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weight
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a measure of the gravitational attraction of a body to Earth (or other such object)
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primary SI units of measurement: mass, length, volume
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kilogram, meter, cubic meter
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accuracy
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how closely a measured value agrees with the correct value
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precision
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how closely individual measurements agree with one another
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dimensional analysis
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calculation based problem solving
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unit factor method
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a technique used to perform unit conversions
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density
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mass per unit volume; D = m/V
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specific gravity
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the ratio of the density of a substance to the density of water, both at the same temperature
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density of water
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1.000 g/mL at 3.98˚C
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temperature
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measures the intensity of heat of a body
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heat
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a form of energy; always flows spontaneously from a hotter body to a colder body (never reverse)
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Kelvin (K)
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the basic unit of temperature in the SI system
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joule (J)
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the SI unit of energy and work; defined as 1 kg·m2/s2
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calorie
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a unit of heat energy defined as 4.184J; originally defined as the amount of heat required to raise the temperature of one gram of water from 14.5˚C to 15.5˚C
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specific heat
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the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius (or kelvin) with no change in phase
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heat capacity
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the amount of heat required to raise the temperature of a body 1˚C.
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temperature scale conversions
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˚F = 1.8˚C+32˚; ˚C = (˚F - 32˚)/1.8; K = ˚C+273
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allotropic modifications (allotropes)
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different forms of the same element in the same physical state
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anhydrous
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without water
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anion
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an ion with a negative charge
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atom
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the smallest particle of an element that maintains its chemical identity through all chemical and physical changes
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atomic mass unit (amu)
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one twelfth of the mass of an atom of the carbon-12 isotope; a unit used for stating atomic formula weights
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atomic number
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the number of protons in the nucleus of an atom
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atomic weight
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weighted average of the masses of the constituent isotopes of an element; the relative mass of atoms of different elements
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Avogadro's number
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6.022 x 1023 units of a specified item
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Cation
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ion with a positive charge
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chemical formula
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combination of symbols that indicates the chemical composition of a substance
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composition stoichiometery
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describes the quantitative (mass) relationships among elements in compounds
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empirical formula/simplest formula
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the smallest whole-number ratio of atoms present in a compound
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formula unit
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the smallest repeating unit of a substance - for non-ionic substances, the molecule
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formula weight
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the mass, in atomic mass units, of one formula unit of a substance. Numerically equal to the mass, in grams, of one mole of the substance. This number is obtained by adding the atomic weights of the atoms specified in the formula
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hydrate
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a crystalline sample that contains water and another compound in a fixed mole ratio. Examples include: CuSO4 * 5H2O and (COOH)2 * 2H2O
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ion
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an atom or group of atoms that carries an electric charge (cations and anions)
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ionic compound
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a compoun that is composed of cations and anions; example: sodium cloride, NaCl
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Law of Multiple Proportions
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when two elements, A and B, form more than one compound, the ratio of the masses of element B that combine with a given mass of element A in each of the compounds can be expressed by small whole numbers
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molar mass
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the mass of a substance in one mole of the substance; numerically equally to the formula weight of the substance
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mole
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6.022 x 1023 (Avogadro's number of) formula units (or molecules, for a molecular substance) of the substance under discussion; the mass of one mole, in grams, is numerically equal to the formula (molecular) weight of the substance
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molecular fomula
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a formula that indicates the actual number of atoms present in a molecule of a molecular substance
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molecular weight
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the mass, in atomic mass units, of one molecule of a nonionic (molecular) substance. Numerically equal to the mass, in grams, of one mole of such a substance; this number is obtained by adding the atomic weights of the atoms specified in the formula
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molecule
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the smallest particle of an element or a compound that can have a stable independent existence
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percent composition
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the mass percentage of each element in a compound
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percent purity
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the mass percentage of each element in a compound
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polyatomic
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consisting of more than one atom; element examples: Cl2, P4, and S8; ion examples: ammonium ion, NH4+, and sulfate ion, SO42-
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stoichiometry
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description of the quantitative relationships among elements in compounds (composition stoichiometry) and among substances as they undergo chemical changes (reaction stoichiometry)
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structural formula
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a representation that shows how atoms are connected in a compound
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actual yield
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the amount of a specified pure product actually obtained from a given reaction
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chemical equation
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description of a chemical reaction by placing the formulas of reactants on the left and the formulas of products on the right of an arrow; it must be balanced - that is, it must have the same number of each kind of atom on both sides
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concentration
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the amount of solute per unit volume or mass of solvent or of solution
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dilution
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the process of reducing the concentration of a solute in a solution, usually simply by adding more solvent
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limiting reactant
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a substance that stoichiometrically limits the amount of product(s) that can be formed
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molarity (M)
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the number of moles of solute per liter of solution
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percent by mass
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100% multiplied by the mass of a solute divided by the mass of the solution in which it is contained
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percent yield
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100% times actual yield divided by theoretical yield
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products
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substances produced in a chemical reaction
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reactants
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substances consumed by a chemical reaction
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reaction ratio
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the relative amounts of reactants and products involved in a reaction; may be the ratio of moles, or masses
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reaction stoichiometry
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description of the quantitative relationships among substances as they participate in chemical reacions
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sequential reaction
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a chemical process in which several reaction steps are required to convert starting materials into products
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solute
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the dispersed (dissolved) phase of a solution
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solvent
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the dispersing medium of a solution
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theoretical yield
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the maximum amount of a specified product that could be obtained from specified amounts of reactants, assuming complete consumption of the limiting reactant according to only one reaction complete recovery of the product
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acid
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a substance that produces H+ (aq) ions in aqueous solution; strong acids ionize completely or almost completely in dilute aqueous solution; weak acids ionize only slightly
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acid-base reaction/neutralization reaction
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the reaction of an acid with a base to form a salt; often, the reaction of hydrogen ions with hydroxide ions to form water molecules
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active metal
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a metal that readily loses electrons to form cations
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activity series
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a listing of metals (and hydrogen) in order of decreasing activity
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alkali
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elements of Group IA in the periodic table, except hydrogen
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alkaline earth metals
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Group IIA elements in the periodic table
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base
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a substance that produces OH- (aq) ions in aqueous solution; strong bases are soluble in water and are completely dissociated; weak bases ionize only slightly
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binary acid
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a binary compound in which H is bonded to a nonmetal in Group VIIA or a nonmetal other than oxygen in Group VIA
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binary compound
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a compound consisting of two elements; may be ionic or molecular
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chemical periodicity
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the variation in properties of elements with their positions in the periodic table
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combination reaction
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reaction in which two substances (elements or compounds) combine to form one compound
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decomposition reaction
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reaction in which a compound decomposes to form two or more products (elements, compounds, or some combination of these)
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displacement reaction
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a reaction in which one element displaces another from a compound
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disproportionation reaction
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a redox reaction in which the oxidizing agent and the reducing agent are the same element
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dissociation
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in aqueous solution, the process in which a solid ionic compound separates into its ions
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electrolyte
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a substance whose aqueous solutions conduct electricity
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formula unit equation
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an equation for a chemical reaction in which all formulas are written as complete formulas
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gas-formation reaction
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a metathesis reaction in which an insoluble or slightly soluble gas is formed as a product
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group (family)
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the elements in a vertical column of the periodic table
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halogens
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Group VIIA elements in the periodic table
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ionization
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in aqueous solution, the process in which a molecular compound separates to form ions
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metal
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an element below and to the left of the stepwise division (metalloids) of the periodic table; about 80% of the known elements
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metalloids
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elements with properties intermediate between metals and nonmetals: B, Si, Ge, As, Sb, Te, Po, and At
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metathesis reaction
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a reaction in which the positive and negative ions in two compounds "change partners," with no change in oxidation numbers, to form two new compounds
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net ionic equation
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an equation that results from cancelling spectator ions from a total ionic equation
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noble (rare) gases
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elements of Group VIIIA in the periodic table
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nonelectrolyte
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a substance whose aqueous solutions do not conduct electricity
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nonmetals
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elements above and to the right of the metalloids in the periodic table
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oxidation
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an increase in oxidation number; corresponds to a loss of electrons
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oxidation-reduction reaction/redox reaction
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a reaction in which oxidation and reduction occur
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oxidation numbers/oxidation states
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arbitrary numbers that can be used as mechanical aids in writing formulas and balancing equations; for single-atom ions they correspond to the charge on the ion; less metallic atoms are assigned negative oxidation numbers in compounds and polyatomic ions
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oxidizing agent
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the substance that oxidizes another substance and is reduced
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period
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the elements in a horizontal row of the periodic table
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periodic law
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the properties of the elements are periodic functions of their atomic numbers
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periodic table
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an arrangement of elements in order of increasing atomic number that also emphasizes periodicity
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precipitate
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an insoluble solid that forms and separates from a solution
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precipitation reaction
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a reaction in which a solid (precipitate) forms
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pseudobinary ionic compound
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a compound that contains more than two elements but is named like a binary compound
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reducing agent
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the substance that reduces another substance and is oxidized
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reduction
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a decrease in oxidation number; corresponds to a gain in electrons
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reversible reaction
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a reaction that occurs in both directions; described with double arrows
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salt
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a compound that contains a cation other that H+ and an anion other than OH- or O2-
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semiconductor
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a substance that does not conduct electricity at low temperatures but does so at higher temperatures
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spectator ions
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ions in solution that do not participate in a chemical reaction; they do not appear in net ionic equations
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strong acid
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an acid that ionizes (separates into ions) completely, or very nearly completely, in dilute aqueous solution
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strong electrolyte
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a substance that conducts electricity well in dilute aqueous solution
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strong base
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metal hydroxide that is soluble in water and dissociates completely in dilute aqueous solution
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ternary acid
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a ternary compound containing H, O, and another element, usually a nonmetal
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ternary compound
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a compound consisting of three elements; may be ionic or molecular
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total ionic equation
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an equation for a chemical reaction written to show the predominant form of all species in aqueous solution or in contact with water
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weak acid
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an acid that ionizes only slightly in dilute aqueous solution
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weak base
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a molecular substance that ionizes only slightly in water to produce an alkaline (base) solution
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weak electrolyte
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a substance that conducts electricity poorly in dilute aqueous solution
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absorption spectrum
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the spectrum associated with the absorption of electromagnetic radiation by atoms (or other species) resulting from transitions from lower to higher energy states
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alpha (a) particle
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a helium ion with a 2+ charge; an assembly of two protons and two neutrons
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angular momentum quantum number (l)
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the quantum mechanical solution to a wave equation that designates the subshell, or set of orbitals (s, p, d, f), within a given main shell in which an electron resides
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anode
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in a cathode-ray tube, the positive electrode
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atomic orbital
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the integral number of protons in the nucleus; defines the identity of an element
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Aufbau ("building up") Principle
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a guide for predicting the order in which electrons fill subshells and shells in atoms
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Balmer-Rydberg equation
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an empirical equation that relates wavelengths in the hydrogen emission spectrum to integers
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canal ray
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a stream of positively charged particles (cations) that moves toward the negative electrode in a cathode-ray tube; observed to pass through canals in the negative electrode
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cathode
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in a cathode-ray tube, the negative electrode
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cathode ray
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the beam of electrons going from the negative electrode toward the positive electrode in a cathode-ray tube
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cathode-ray tube
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a closed glass tube containing a gas under low pressure, with electrodes near the ends and a luminescent screen at the end near the positive electrode; produces cathode rays when high voltage is applied
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continuous spectrum
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the spectrum that contains all wavelengths in a specified region of the electromagnetic spectrum
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d orbitals
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beginning in the third shell, a set of five degenerate orbitals per shell, higher in energy than s and p orbitals in the same shell
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degenerate orbitals
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two or more orbitals that have the same energy
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diamagnetism
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weak repulsion by a magnetic field; associated with all electrons being paired
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electromagnetic radiation
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energy that is propagated by means of electric and magnetic fields that oscillate in directions perpendicular to the direction of travel of the energy
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electron
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a subatomic particle having a mass of 0.00054858 amu and a charge of 1-
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electron configuration
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the specific distribution of electrons in the atomic orbitals of atoms and ions
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electron transition
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the transfer of an electron from one energy level to another
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emission spectrum
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the spectrum associated with emission of electromagnetic radiation by atoms (or other species) resulting from electron transitions from higher to lower energy states
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excited state
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any energy state other than the ground state of an atom, ion, or molecule
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f orbitals
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beginning in the fourth shell, a set of seven degenerate orbitals per shell, higher in energy than s, p, and d orbitals in the same shell
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ferromagnetism
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the property that allows a substance to become permanently magnetized when placed in a magnetic field; exhibited by iron, colbalt, and nickel
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frequency (v)
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the number of crests of a wave that pass a given point per unit time
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fundamental particles
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subatomic particles of which all matter is composed; protons, electrons, and neutrons are fundamental particles
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ground state
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the lowest energy state or most stable state of an atom, molecule, or ion
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Heisenberg Uncertainty Principle
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it is impossible to determine accurately both the momentum and position of an electron simultaneously
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Hund's Rule
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each orbital of a given subshell is occupied by a single electron before pairing begins
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isotopes
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two or more forms of atoms of the same element with different masses; that is, atoms containing the same number of protons but different number of neutrons
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line spectrum
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an atomic emission or absorption
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magnetic quantum number (ml)
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quantum mechanical solution to a wave equation that designates the particular orbital within a given subshell (s, p, d, f) in which an electron resides
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mass spectrometer
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an instrument that measures the charge-to-mass ratios of charged particles
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natural radioactivity
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spontaneous decomposition of an atom
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neutron
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a subatomic nuclear particle having a mass of 1.0087 amu and no charge
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nucleus
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the very small, very dense, positively charged center of an atom containing protons and neutrons, except for 11H
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nuclide symbol
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