Chem 1070 1st EditionExam # 2 Study Guide Lectures: 7-14Lecture 7 (February 10)Isotopes Notation for isotopes:Mass number = A = the number of protons + neutronsNumber of protons = zXProtons – Mass number Lecture 8 (February 12) FormulasWhen writing formulas look at the periodic table and see what group the elements are in to see how many available electrons they have. You also have to list the MOST metallic element first, they are located on the LEFT side of the periodic table.*for non-metallic elements list them: C P N H S I Br Cl O FLecture 9 (February 17)Binary acids only have 2 elements, one of those is always hydrogen which is then paired with another non-metal.An Oxo-acid is an acid containing oxygen and hydrogen and at least one other element.Formula MassThe equation for formula mass is as follows: (# of atoms in 1st element x Atomic mass of 1st element)+(# of atoms in the 2ndelement x Atomic mass of 2nd element)Lecture 10 (February 19)MolesAtoms are too small and numerous to count individually so we use Avagadros number 6.022 x 10^23 (moles) to count the mass percent of composition, in 1 mole of elephants there are 4 legsper elephant so you would multiply 4 x 6.022 x 10^23 getting 2.409 x 10^24.Molar MassIn chemistry, the molar mass M is a physical property. It is defined as the mass of a given substance (chemical element or chemical compound) divided by its amount of substance. The base SI unit for molar mass is kg/mol. However, for historical reasons, molar masses are almost always expressed in g/mol. Grams per mole (g/mol) of atoms per element. Molar mass = Atomicmass (amu)BridgesDensity: Mass <-> VolumeAvagadros Number: Mole A <-> Item AMolar Mass: Mole A <-> Grams AMole Ratio: Mole A <-> Mole BLecture 11 (February 24)The molecular formula is the way a compound is written such as C2H4O2 which is acetic acid or vinegar. But the Empirical formula is the way the formula is written with the smallest whole number ratios. This example would have been C1H2O1 or CH2O. In order to find the smallest whole number ratio, you must divide by the smaller number then times the next number by a number that would cause it to be a whole number. For example: C1.4H3.15 you would divide by 1.4 to get C1H2.25, then you would multiply both numbers by 4 (to get 2.25 to a whole number)so you would get C4H9.Evidence of Chemical Reactions 1. Change in Color2. Forms a Solid (Precipitation)3. Forms a Gas (Gas Evolution)4. Emits Light5. Absorbs or Emits Heat (Endo- or Exo- Thermic)Lecture 12 (February 26)Balance equations "by inspection" with these steps:1 Check for diatomic molecules.2 Balance the metals (not Hydrogen).3 Balance the nonmetals (not Oxygen).4 Balance oxygen.5 Balance hydrogen.6 The equation should now be balanced, but recount all atoms to be sure.Reduce coefficients (if needed).Lecture 13 (March 3)Acid-Base reactionsAcid + Base = salt + waterREDOX Reactions- An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electronLecture 14 (March 5)-Synthesis ReactionsA + B = ABDecomposition ReactionAB = A + BSingle Displacement Reactions A + BC = AC +BDouble DisplacementAB + CD = AD +