Exam 1 Concept Review Chapter 1 TERMS Atom The smallest particle of an element that retains the characteristic chemical properties of that element Chemical bond an attraction between atoms that allows the formation of chemical substances that contain two or more atoms Chemical change one or more substances are transformed into new substances Results in a change in the composition of a material Chemical compound a pure substance that is the chemical combination of two or more elements Can be reduced to two elements Made of molecules or ions Chemical equation symbolic representation of a chemical reaction Reactants on the left products on the right Chemical formula a way of expressing information about the proportions of atoms that constitute a particular chemical compound Chemical property any of a material s properties that becomes evident during a chemical reaction Density mass volume Extensive Property depend upon the amount of substance mass Element a pure substance consisting of a single type of atom Heterogeneous not the same throughout Homogenous same throughout Hypothesis A tentative explanation or prediction based on experimental observations Intensive property does not depend upon the amount of a substance density Ion An atom or group of atoms that have lost or gained one or more electrons so that it is no longer electrically neutral Kinetic energy energy is energy associated with motion Kinetic molecular theory 1 A gas consists of a collection of small particles traveling in straight line motion and obeying Newton s Laws 2 The molecules in a gas occupy no volume 3 Collisions between molecules are perfectly elastic that is no energy is gained or lost during the collision 4 There are no attractive or repulsive forces between the molecules 5 The average kinetic energy of a molecule is 3kT 2 Therefore the average KE is based on temperature Law A concise verbal or mathematical statement of a behavior or a relation that seems always to be the same under the same conditions Macroscopic can be seen by the human eye Molecule the smallest unit of a compound that retains its chemical characteristics Particulate microscopic Periodic table chart on last page Physical change the identity of a substance is preserved though it may have changed physical state No new substance is made Physical property Characteristics that can be evaluated without changing the composition of the material Color State solid liquid or gas Melting and Boiling point Density mass unit volume Products right side of chemical equation Qualitative No numbers involved ie color or appearance Quantitative quantity specified by measureable units Reactants left side of chemical equation Solution homogeneous mixture of one or more solutes dissolved in a solvent State solid liquid or gas Submicroscopic too small to be seen by a light microscope Measured by K Temperature measures heat Theory a well tested unifying principle that explains a body of facts and the laws based on them It is capable of suggesting new hypotheses that can be tested experimentally LEARNING OBJECTIVES Understand the differences between hypothesis law and theory A theory is well tested and explains a principle Laws are based off of theories and can be tested with hypothesis Apply the kinetic molecular theory to explain properties of matter All particles have energy but the energy varies depending on the temperature the sample of matter is in which determines its state of matter Least to greatest energy solid liquid gas The temperature of a substance is a measure of the average kinetic energy of the particles A change in phase may occur when the energy of the particles is changed There are spaces between particles of matter The average amount of empty space between molecules gets progressively larger as a sample of matter moves from the solid to the liquid and gas phases There are attractive forces between atoms molecules and these become stronger as the particles move closer together These attractive forces are called intermolecular forces Classify matter Classify according to physical state solid liquid gas Classify by composition element compound mixture Chemical Physical properties vs changes Properties are characteristics that can be evaluated while changes physical changes preserve composition of chemicals but may have changed states and chemical changes create a new substance Chapter 2 TERMS Anhydrous Compound Any class of hydrocarbons characterized by the presence of a benzene ring or a related structure Allotrope nonmetals is that a particular element can often exist in several different and distinct form each having its own properties Anion negative charge due to gaining e Actinides series between actinium and rutherfordium on the periodic table Atomic mass of protons neutrons Based on Carbon 12 Atomic number of protons in a nucleus Atomic weight The atomic masses on the periodic table are weighted averages of the all of an element s individual isotope masses Avogrado s number 6 022E23 Cation positive charge due to losing e Condensed formula indicates how certain atoms are grouped together Colomb s Law governs electrostatic forces Crystal lattice results in a clean break when an ionic solid breaks and ions attract to nearest neighbors Electrostatic forces A metal atom can transfer an electron to a nonmetal atom The resulting cation and anion are attracted to each other by electrostatic forces Emperical formula show only the simplest ratio of atoms in the formula Ionic compounds are represented by their empirical formula Formula Unit The simplest ratio of ions in an ionic compound similar to the molecular formula of a molecular compound Formula weight Halide ion ions of the elements in group 7A of the periodic table As strong as electrolytes Compounds with aluminum Hydrated compounds A compound in which molecules of water are associated with ions Ionic compound bond between a metal and a non metal Charge is neutral 1A 3A lose e cations 5A 7A gain e anions Isotope atoms of the same element that have a different number of neutrons Same element same number of protons Different mass different number of neutrons Law of chemical periodicity the properties of the elements are periodic functions of atomic number Mass number the sum of protons and neutrons Remember that all atoms of the same element will have the same atomic number so the subscript Z is often left out Molar mass the mass in grams of one mole of particles of any substances Mole The
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