Test Answers on Chemistry Definitions – Flashcards
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| chemistry |
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| the study of the properties and the composition of matter |
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| element |
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| a pure substance that cannot be broken into simpler substances by chemical means |
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| compound |
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| a pure substance that can be broken down by chemical means to produce two or more pure substances |
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| the Modern Periodic Law |
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| when elements are arranged in order of increasing atomic number, their properties show a periodic recurrence and gradual change |
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| isotopes |
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| atoms of the same element that have the same number of protons but different number of neutrons |
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| radio isotopes |
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| isotopes that are unstable giving off radiation |
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| atomic radius |
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| the distance from the center of the nucleus to the valence electron |
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| first ionization energy |
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| the amount of energy required to remove the most weakly held electron from a neutral atom |
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| electron affinity |
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| the amount of energy given off when an electron is accepted by an atom in the gaseous state |
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| electronegativity |
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| a number that describes the relative ability of an atom to attract electrons when bonding |
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| chemical bond |
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| the force of attraction holding atoms or ions together |
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| ionic bond |
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| the attraction between oppositely charged ions in a compound |
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| covalent bond |
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| the attractive force between two atoms that result when electrons are shared |
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| Lewis structures |
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| illustrations of molecules formed from covalent bonding and using Lewis symbols |
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| polar covalent bond |
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| a covalent bond with unequal sharing of electron in the bond |
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| intramolecular forces |
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| attractive forces between atoms and ions within a compound (these are bonds) |
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| intermolecular forces |
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| attractive forces between molecules |
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| IUPAC |
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| International Union of Pure and Applied Chemistry |
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| valence |
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| the charge of an ion |
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| polyatomic ion |
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| a covalently bonded group of atoms, possessing a net charge |
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| oxyanions |
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| polyatomic ions that contain oxygen and have a negative charge |
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| law of conservation of mass |
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| during a chemical reaction, the total mass of the reactants is always equal to the total mass of the products |
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| the law of definite proportions |
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| a specific compound always contains the same elements in definite proportions by mass |
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| mole |
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| the amount of substance containing 6.02 x 1023 entities |
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| molar mass |
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| the mass, in grams, of one mole of a substance |
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| empirical formula |
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| shows the simplest whole number ratio of atoms or ions in a compound |
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| gravimetric stoichiometry |
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| the procedure for calculating the masses of reactants or products in a chemical reaction |
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| limiting reagent |
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| the reactant that is completely consumed in a chemical reaction |
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| excess reagent |
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| the reactant that is present in more than the required amount for complete reaction |
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| actual yield |
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| the amount of product that is actually obtained experimentally |
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| theoretical yield |
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| the amount of product that we predict will be obtained, calculated using stoichiometry |
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| solution |
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| a homogeneous mixture of substances composed of at least one solute and one solvent |
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| homogeneous |
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| a uniform mixture of only one phase (visible part) |
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| heterogeneous mixture |
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| a non-uniform mixture of two or more phases |
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| solute |
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| a substance that is dissolved in a solvent |
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| solvent |
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| the medium in which a solute is dissolved |
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| concentration |
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| the quantity of a given solute in a given amount of solution |
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| dilute |
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| having a relatively small concentration |
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| standard solution |
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| a solution for which the precise concentration is known |
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| unsaturated solution |
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| a solution containing less than the maximum quantity of a solute at specific temperature and pressure conditions |
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| saturated solution |
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| a solution containing the maximum quantity of a solute at specific temperature and pressure conditions |
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| supersaturated solution |
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| the state of a solution when the solution contains more than the maximum quantity of a solute at specific temperature and pressure conditions |
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| solubility |
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| the amount of solute that can dissolve in a certain amount of solvent at a specific temperature and pressure |
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| precipitate |
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| the insoluble solid formed in a chemical reaction involving two solutions |
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| immiscible |
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| when two liquids do not form a homogeneous mixture when added together (do not form a solution when mixed) |
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| miscible |
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| when two liquids form a homogeneous mixture when added together (forms a solutions when mixed in any proportion) |
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| acid |
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| any substance that produces hydrogen ions in water |
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| base |
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| any substance that produces hydroxide ions in water |
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| dissociation |
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| the separation of ions |
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| ionization |
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| the production of ions from a neutral molecule |
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| pH |
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| potency of hydrogen |
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| solids |
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| mainly vibrational motion so particles stay relatively close together |
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| liquids |
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| have some of each type of motion |
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| gases |
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| have all types of motion but translation motion is predominate |
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| Kinetic Molecular Theory |
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| particles can have three main types of motion: translational (straight line), rotational (spinning), and vibrational (back and forth motion of atoms within the molecule) |
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| Boyle’s Law |
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| At a constant temperature, the volume of a fixed mass of gas in inversely proportional to its pressure |
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| Charles’ Law |
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| At a constant pressure, the volume of a fixed mass of gas is directly proportional to its Kelvin temperature. |
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| Gay-Lussac’s Law |
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| At a constant volume, the pressure of a fixed mass of gas is directly proportional to its Kelvin temperature. |
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| molar volume |
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| the volume occupied by one mole of a substance |
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| Avogadro’s hypothesis |
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| equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. |
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| organic compounds |
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| compounds that contain carbon, except CO, CO2, and ionic compounds with carbon |
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| hydrocarbons |
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| organic compounds containing only one carbon and hydrogen atoms |
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| isomer |
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| a compound with the same molecular formula as another compound, but a different structural formula |
