Pre-Diploma Chemistry Exam Study Guide

Part I: Bonding A) Group # and Valence Electrons
-is used to describe the column in which an element is in.
i.e., Lithium is in group 1.
*Group number tells you how many valence electrons a specific element has.
i.e., Aluminum has 3 valence electrons. B) Ionic Bonding
-Ionic bonds form F.U.'s (formula units)
-A bond between a metal and a non metal
-Occurs when an atom has lost or gained an electron
**BRING YOUR ION SHEET FOR NAMING** C) Covalent Bonding
-Covalent bonds form molecules.
-Bond between two metals or two nonmetals.
-Electrons are shared between the two elements.
**NEED TO KNOW HOW TO DO A LEWIS STRUCTURE** Part II: Types of Reactions
(You'll need to identify the type of reaction and predict the products) A) Single Replacement
-these can be cationic or anionic.
i.e. Cationic: A+BC-->AC+B Anionic: A+BC-->AB+C
B) Double Replacement
-AB+CD-->AD+CB

C) Composition/Synthesis
-A+B-->AB

D) Combustion
-C(x)+H(y)+O(2)-->CO(2)+H(2)O

Part III: Stoichiometry A) All conversions using the mole, including GFM.
-Mole (Avogadro's #) = 6.02 x 10^23
QUANTITY MOLE MASS
GFM: Number on periodic table. B) Conversions using 1 mole = 22.4L (self explanatory) C) Conversions i.e. 2Bread + 3PeanutButter --> 1Sandwich
How many pieces of bread are required to make 6 sandwiches if I have an excess of peanut butter? 6 sandwiches x 2 bread = 12 Breads. 1 sandwich More examples? Ask. D) Limiting and Excess Reactants Some chemical reactions involve random amounts of reactants. The reaction will stop when one or more of the reactants run out. (limiting) ex. 2Bread + 3 HamSlices --> 1Sandwich How many sandwiches can you make from 21 pieces of ham and 20 pieces of bread? 20B x 1S = 10S 21H x 1S=7S 2B 3H The smaller of answer from the 2 givens is the answer. The reactant that produced the smaller amount is called the limiting reactant. (in this case, ham) Part IV: Gas Laws A) Boyle's Law: States tgat pressure varies indirectly with volume. (In other words, as one goes up, the other goes down.) P(1)V(1) = P(2)V(2) B) Charles' Law: States that temperature varies directly with volume. (In other words, when one goes up, the other goes up.)
*TEMPERATURE MUST BE IN KELVINS V(1)/T(1) = V(2)/T(2) C) Combined Gas Law: Gay Lussac's Law.
-Pressure and temperature are directly related. P(1)/V(1) = P(2)/V(2) THE COMBINED GAS LAW: P(1)V(1)/T(1) = P(2)V(2)/T(2)