Term | Definition |
Accuracy | the exactness of a measurement (need two things: true/accepted value and observed/expiremental value) |
Precision | the closeness of a set of numbers to each other (need several data points) |
Significant Figures | indicate the precision of a measurement |
Scientific Notation | shorthand for long numbers... A x 10^n |
Mass | the quantity of matter an object contains |
Weight | the pull on an object by gravity |
Density | how tightly packed the particles of an object are (D = m/v) |
Volume | how much space something takes up (V = m/d) |
Specific Gravity | comparison of the density of a substance to the desity of a ref. sub., generally water, at the same temp. SG = den of sub /den of ref (both in g/cm^3) NO UNIT |
Kelvin conversions | K = C + 273 C = K - 273 |
Chemistry | the study of the compostion of substances and the changes they undergo |
Pure chem. | knowledge for its own sake |
Organic chem. | study of all things with carbon |
Inorganic chem. | study of all things without carbon |
Analytical chem. | study of the composition of sub. |
Physical chem. | study of the behavior of chemicals |
Biochem. | chem. of living organisms |
Theory | a tested hypothesis, can't be proved |
Scientific Law | a statement of a natural fact, no explination |
Matter | anything that takes up space and has mass |
Substance | a particular kind of matter that has a uniform and definate composition |
Physical property | a quality or condition that can be observed or measured w/out changing sub.'s comp. |
Solid | has definate shape and volume |
Liquid | has def. volume, no definate shape |
Gas | no definate volume or shape |
Vapor | something that is currently in a gaseous state, but is usually liquid or solid at room temperature |
Mixture | a physical blend of two or more substances |
Phase | any part of a system with uniform comp and properties |
Elements | the simplest forms of matter that can exist under normal lab conditions |
Heat | the amount of energy that is transferred b/c of a change in temp. |
Isotope | an atom of an element that has the same number of protons, but a different number of neutrons (Chemically the same as normal- e + p det. prop.) |
QMM | Quantum Mechanical Model- the most current model of the atom. It explains the behavior of electrons. Approx. area, rather than exact path. |
electron configuration | elem. symbol + electrons for each sublevel using superscripts |
Aufbau's Principle | electrons seek to fill the area with the least energy first |
Orbital Notation | elem. sybol + lines and arrows to show elec. for each sublevel |
Pauli's Exclusion Principle | no two elec. can have the same set of quantum numbers (arrows can't point same direction. Up first.) |
Hund's Rule | when there are several orbitals of equal energy, one electron in each before adding second to any. |
Valence electrons | the electrons on the highest energy level of an atom |
Properties of metals | high conductivity, high luster when clean, ductile (can be drawn into wire), malleable (can be flattened), solid at rm. temp. EXCEPT MERCURY |
Properties of Nonmetals | nonlustrous, poor conductors, some gases, some solids, ONE liquid (Bromine) |
Mettalloids | on border between metals and nonmetals, properties of both |
Ion | an atom or group of atoms with a charge, due to extra or missing electrons |
Cation | positive charge, formed from a metal |
Anion | negative charge, formed from a nonmetal |
Compound | composed of two or more different elements chemically combined |
Molecule | an electrically neutral group of atoms that act as a unit |
Molecular compound | made up of molecules |
Ionic compound | made up of ions |
Solution | another name for a homogeneous mixture |
Octet Rule | atoms will gain or lose electrons in order to match the nearest noble gas |
Formula Unit | the lowest whole number ratio of ions in an ionic compound |
Law of Definate Proportions | the identity of a substance depends on the ratio of its elements |
Stoichiometry | the calculation of quantities in chemical equations |
Electronegativity | the tendency of atoms of an element to attract electrons when the atom is chemically combined with another atom. |