Indicate which of the following numbers is an exact number: (a) 50,247 tickets were sold at a sporting event; (b) 750 mL of water was used to make a birthday cake; (c) 10 eggs were used to make a breakfast; (d) 0.41 g of oxygen was inhaled in each breath; (e) Earth orbits the sun every 365.24 days.
Chemistry Test Study Guide Molecules determine the behavior of ____ Matter Break apart H2O 2hydrogen atoms bounded to 1 oxygen atom H2O is water . . . H2O2 is hydrogen peroxide. Why did the element change We changed the subscript Determine the number of each type of atom in glucose, which has the molecular formula C6H12O6 Carbon atoms=6 Hydrogen atoms=12 Oxygen Atoms=6 Determine the number of each type of atom in Pb(C2H3O2)2 Pb=2 C=4 H=6 O=4 Elements with unstable electron configurations form compounds with other elements to ____ Gain Stability Metals ___ electrons, Nonmetals ___ electrons Lose, gain Compounds formed between a metal and at least one nonmetal are _____. Compounds formed between nonmetals are _____ Ionic, Molecular SO2 is (Molecular/Ionic) S and O (nonmetals) so molecular Formula mass of a compound is analogous to the _______ of an element Atomic mass The formula mass of a compound in amu is numerically equivalent to its molar mass in __ (g/mol) If an element occurs in only one compound, balance that element ____ First Change only occurs in ________ never subscripts Coefficients Propane, C3H8, is often used in place of methane, CH4, as a fuel for home heating and cooking. Much like methane, if burns in (reacts with) oxygen to produce carbon dioxide (CO2) and water (H2O). Balance the reaction for the burning propane in oxygen. The unbalanced equation: C3H8 + O2 → CO2 + H2O First, balance the elements present in only one compound on each side of the equation. C3H8 + O2 → 3CO2 + H2O 3 C’s on each side C3H8 + O2 → 3CO2 + 4H2O 8 H’s on each side Balance the element present as a free element last. C3H8 + 5O2 → 3CO2 + 4H2O 10 O’s on each side Final balanced equation: C3H8 + 5O2 → 3CO2 + 4H2O Note: The absence of coefficient in front of a reactant or product implies a “1”. What are the two bond types Ionic: valence electrons are transferred Covalent: valence electrons are shared Bond formation results in formation of full outer Bohr orbits. Because this stable configuration typically involves eight electrons, this is commonly known as the ______ OCTET rule Noble gasses are already ____ Stable Element symbol surrounded by a number of dots equal to the number of ______ Valence electrons Elements without an octet tend to react with other elements to form an octet, except _____ which reacts to form a duet Hydrogen Since ionic bonding involves the transfer of electrons from a metal to a nonmetal, the Lewis structure for an ionic compound involves moving dots. The metal becomes a/an ______ and the nonmetal becomes an/a _____ Cation, Anion The metal and the nonmetal each acquire _______ in the formation of an ionic bond A charge Covalent bonds involve the _______ Sharing of electrons Sometimes multiple bonding pairs are necessary to complete the octets for each atom in the_____ Lewis structure Resonance in zone is the averaging for ______ Lewis structures. Two identical Valence Shell Electron Pair Repulsion Theory (VSEPR theory) allows us to predict _________ from their Lewis structures Module shape Of the millions of known compounds in our world _____have a single element in common 95% The study of carbon containing compounds and their chemistry is called __________ organic chemistry Inorganic Compounds came from _______ earth Hydrocarbons contain _____________ only carbon and hydrogen Functionalized Hydrocarbons contain additional __________ of atoms called functional groups Atoms or groups Alkanes contain ____________ only single bonds Alkenes contain ____________ one or more double bonds Alkynes contain _____________ one or more triple bonds Aromatics contain ___________ six-carbon rings called aromatic rings Carbon-hydrogen bonds are mostly _________ Methane’s tetrahedral; geometry makes it a nonpolar molecule Nonpolar Alkanes are ________; they only contain he maximum number of hydrogen atoms per carbon atom Saturated Alkenes and alkynes are ________. They contain at least one _______ bond. Unsaturated , double or triple