Chapter 1 and 2 vocab – Flashcards
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| allotropes |
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| different forms of the same element that exist in the same physical state under the same conditions of temperature and pressure. |
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| atom |
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| the smallest particle of an element that can be involved in chemical combination with another element |
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| boiling point |
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| the temperature at which the equilibrium vapor pressure of a liquid equals the external pressure on the liquid |
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| Celsius temperature scale |
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| a scale defined by the freezing (0 C) and boiling point (100 C) of pure water at 1 atm |
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| chemical change |
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| a process in which substances (reactants) change into other substances (products)by rearrangement, combination, or separation of atoms |
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| chemical compound |
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| a pure substance that can be decomposed into two or more different pure substances |
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| chemical element |
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| a substance that cannot be decomposed into two or more new substances by chemical or physical means |
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| chemical formula |
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| a notation combining element symbols and numerical subscripts that shows the relative numbers of each kind of atom in a molecule or formula unit of a substance |
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| chemical property |
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| describes the kinds of chemical reactions that chemical elements or compounds can undergo |
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| chemical reaction |
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| a process in which substances change into other substances by rearrangements, combination, or separation of atoms |
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| chemistry |
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| the study of matter the changes it undergoes |
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| law of conservation of mass |
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| law stating that there is no detectable change in mass during an ordinary chemical reaction |
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| law of constant composition |
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| law stating that a chemical compound always contains the same elements in the same proportions by mass |
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| conversion factor |
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| a relationship between 2 measurement units derived from the proportionality of one quantity to another,; eg, density is the conversion factor between mass and volume |
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| density |
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| the ratio of the mass of an object to its volume |
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| diatomic molecule |
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| a molecule that contains 2 atoms |
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| dimensional analysis |
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| a method of using units in calculations to check for correctness |
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| energy |
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| the capacity to do work |
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| gas |
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| a phase or state of matter in which a substance has no definite shape and has a volume determined by the volume of its container |
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| heterogeneous mixture |
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| a mixture in which components remain separate and can be observed as individual substances or phases |
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| homogeneous mixture |
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| a mixture of two or more substances in a single phase that is uniform throughout |
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| hypothesis |
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| a tentative explanation for an observation and a basis for experimentation |
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| kinetic molecular theory |
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| the theory that matter consists of nanoscale particles that are in constant, random motion |
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| law |
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| a statement that summarizes a wide range of experimental results and has not be contradicted by experiments |
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| liquid |
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| a phase of matter in which a substance has no definite shape but a definite volume |
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| macroscale |
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| refers to samples of matter that can be observed by the unaided human senses |
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| matter |
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| anything that has mass and takes up space |
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| melting points |
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| the temperature at which the structure of a solid collapses and the solid changes to a liquid |
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| metal |
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| an element that is malleable, ductile, forms alloys, and conducts an electric current |
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| metalloid |
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| an element that has some typically metallic properties and other properties that are more characteristic of nonmetals |
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| microscale |
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| refers to samples of matter so small that they have to be viewed with a microscope |
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| model |
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| a mechanical or mathematical way to make a theory more concrete, such as a molecular model |
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| molecule |
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| the smallest particle of an element or compound that exists independently, and retains the chemical properties of that element or coumpound |
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| law of multiple proportions |
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| when two elements A and B can combine in two or more ways, the mass ratio A:B in one compound is a small-whole-number multiple of the mass ratio A:B in the other compound |
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| nanoscale |
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| members of the family of fullerenes in which graphite-like layers of carbon atoms form cylindrical shapes |
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| nonmetal |
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| element that does not have the chemical and physical properties of a metal |
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| physical changes |
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| changes in the physical properties of a substance, such as the transformation of a solid to a liquid |
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| physical properties |
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| properties that can be observed and measured without changing the composition of a substance |
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| product |
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| a substance formed as a result of a chemical reaction |
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| proportionality factor |
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| a relationship between 2 measurement units derived from the proportionality of one quantity to another |
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| qualitative |
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| in observations, nonnumerical experimental information, such as a description of color or texture |
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| quantitative |
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| numerical information, such as the mass or volume of a substance expressed in appropriate units |
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| reactant |
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| a substance that is initially present and undergoes change in a chemical reaction |
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| solid |
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| a state of matter in which the substance has a definite shape and volume |
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| solution |
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| a homogeneous mixture of 2 or more substances in a single phase |
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| substance |
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| matter of a particular kind; each substance, when pure, has a well-defined composition and set of characteristic properties that differ from the properties of any other substance |
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| temperature |
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| the physical property of matter that determines whether one object can heat another |
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| theory |
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| a unifying principle that explains a body of facts and the laws based on them |
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| atomic mass unit |
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| the unite of a scale of relative atomic masses of the elements |
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| atomic number |
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| the number of protons in the nucleus of an atom of an element |
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| atomic structure |
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| the identity and arrangement of subatomic particles in an atom |
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| atomic weight |
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| the average mass of an atom in a representative sample of atoms of an element |
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| electron |
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| a negatively charged subatomic particle that occupies most of the volume of an atom |
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| ion |
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| an aton or group of atoms that has lost or gained one or more electrons so that it is no longer electrically neutral |
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| isotope |
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| forms of an element composed of atoms with the same atomic number but different mass numbers owing to a difference in the n umber of neutron |
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| mass |
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| a measure of an object's resistance to acceleration |
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| mass number |
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| the number of protons plus neutrons in the nucleus of an atom of an element |
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| mass spectrometer |
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| an analytical instrument used to measure atomic and molecular masses directly |
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| mass spectrum |
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| a plot of ion abundance versus the mass of the ions |
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| metric system |
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| a decimalized measurement system |
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| neutron |
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| an electrically neutral subatomic particle found in the nucleus |
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| nucleus |
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| the tiny central core of an atom |
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| percent abundance |
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| the percentage of atoms of a particular isotope in natural sample of a pure element |
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| proton |
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| a positively charged subatomic particle found in the nucleus |
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| radioactivity |
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| the spontaneous emission of energy and/or subatomic particles byunstable atomic nuclei |
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| scanning tunneling microscope |
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| an analytical instrument that produces images of individual atoms or molecules on a serface |
