CHM 101 1st EditionExam # 1 StudyGuideLecture 1 What is chemistry and its components?- Chemistry is the study of matter and the changes it undergoes - Matter is anything that has mass and occupies space- Matter can undergo physical and chemical changes - Solid- has a definite shape, definite volume, not compressible- Liquid-indefinite shape, definite volume, not compressible- Gas-indefinite shape, indefinite volume, compressible- Pure substance-matter that has a fixed composition and a characteristic set of propertieso Element-substance that cannot be decomposed into simpler substances. An element’s basic unit is an atomo Compound-a chemical combination of two or more elements A compound’s basic unit is a molecule- Mixture- a physical combination of two or more pure substances o Homogeneous mixture-substances are unevenly distributed throughout the mixtureo Homogeneous mixture-substances are evenly distributed throughout*Tip: practice doing conversions*Lecture 2- John Dalton’s Atomic Theoryo Elements are made up of atomso All atoms of a given element are identical in mass and other properties o Atoms cannot be created or destroyedo Atoms from different elements can combine to form compounds - The Law of Constant Compositiono In one compound the number of atoms and type is constant- The Law of Conservation of Mattero When a chemical reaction occurs matter is not created or destroyed - JJ Thompson discovered the electron with a cathode ray tube- Robert Millikano Oil drop experimento Determined the charge of a single electron- Thompson knew matter was neutral and there must also be a positive chargeo Plum-pudding model- Edward Rutherfordo Gold foil experimento Discovered positive nucleus and most of atom is empty space- Atoms have an electron cloud and a positive nucleus- Atomic number- number of protons in the nucleus of an atom of a particular element- Mass number- total number of protons and neutrons in the nucleus of an atom- Isotope- differing number of neutrons in the same elementPeriodic Table- Metals- shiny, good conductors of heat and electricity, except mercury (left side of periodic table)- Non-metals – poor conductors (left on the periodic table)- Metalloids- properties between metals and nonmetals (starts with Boron on the periodic table)- Group 1A – Alkali Metals- Group 2A – Alkaline Earth Metals- Group 6A – Chalcogens- Group 7A – Halogens- Group 8A – Noble gasesLecture 3 - Molecular compounds combination of nonmetals and share electrons- Ionic compounds are between nonmetals and metals- Metals lose electrons to form positive ions called cations- Nonmetals gain electrons to form negative ions called anionsColumn Charge Example1A +1 K+2A +2 Mg2+3A +3 Al3+5A -3 N3-6A -2 S2-7A -1 F-- In naming ionic compounds the metal is named first and transition metals with more than one possible charge have their charge indicatedby roman numerals- Tip: practice balancing equations!Lecture 4 - Combination reactions- 2 or more reactants combine to form one product- Decomposition reactions- reactant breaks down to form 2 or more products - Combustion Reactions- organic compound is burned in O to form water and carbon dioxide- Formula Weight – sum of the atomic weights that make up a formula unit of an ionic compoundLecture 5- Avagadro’s Number (NA) = 6.022 x 1023 mol-1 - The definition of a mole also provides a mass relationshipo 1 amu = 1.66 x 10-24 g For stoichiometry problems - Complete and balance equations- Calculate the molecular weight of required substances- Set up as a dimensional analysis problem with the appropriate stoichiometric ratio- Double check units Lecture 6 - Limiting reactant is completely used up in a chemical reaction- The reactant that produces the least amount of product is the limiting reactant- Theoretical yield – maximum amount of product that can be formed from the limiting reactant in a chemical reaction- Actual Yield – the actual amount of product produced- Percent yield relates theoretical yield to actual yield- actual yield / theoretical yield x
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