Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chemistry 107 - Fall 2009

Exam I Study Guide

Final 2009 version

Review

Quizzes, notes, homework etc..

Terms (be able to define/describe)

Find/learn definitions/descriptions in your notes and/or text: Scientific method, observation, hypothesis, experiment, temperature, relative temperature, absolute temperature, density, solid, liquid, gas, element, compound, mixture, pure substance, homogeneous mixture, heterogeneous mixture, energy, heat, temperature, calorie, joule, specific heat capacity, isotope, proton, electron, neutron, Mass number, Atomic mass, periodicity, ion, metal, non-metal, alkali metal, alkaline earth metal, transition metal, halogen, noble gas, representative element, monatomic, diatomic, cation, anion, binary compounds, periodic table, ionization, ionic compound, formula, polyatomic ion. Molecular weight. Formula weight. Empirical formula. Molecular formula.

Problem solving

Be able to: convert numbers to scientific notation and use numbers expressed in scientific notation; do all calculations with proper significant figures; make all conversions within the metric system (SI), including liters to m3 etc., know prefixes in metric system we discussed (mega-, kilo-, deci-, centi-, milli-, micro-, nano-.), make approximate conversions between American and metric systems (one inch = 2.54 cm exactly; a yard is about a meter; a quart is about a liter). Be able to solve density problems and specific heat problems as we have done in class. Be able to balance simple chemical equations and to work with simple stoichiometry (ratios) problems. Be able to write formulas from names and names from formulas for ionic compounds. Be able to recognize and name bases and the acids we looked at in lecture, and to write formulas of these acids and bases given names. Be able to solve problems and do exercises in your text, except for specific exceptions I have noted (e.g. you need to be able to write formulae for ferric, plumbous, etc. that are listed on the General Chemistry Nomenclature pages, but not chromic etc. Additional examples are available in the Supplemental Study Module). Recall also you ONLY need to memorize the elements on the Periodic Table below:

Periodic Table of the Elements
 IA IIA IIIA IVA VA VIA VIIA VIIIA
1 2 13 14 15 16 17 18
   H  He
Li Be    B C N O F Ne
Na Mg 3 4 5 6 7 8 9 10 11 12  Al Si P S Cl Ar
K Ca   Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
 Rb Sr                  Ag  Cd   Sn     I  Xe
 Cs  Ba        W        Pt Au  Hg    Pb        

Atoms and Atomic Structure

The mass of one mole of carbon twelve. The mass of one atom of carbon twelve. Be able to fill out tables as we did in class for isotopes (for example: given A & Z find numbers of protons, symbol, etc. - some examples are available in the Supplemental Study Module). Predict the charges of the ions of the representative elements. Explain why they have these charges (electronic structure of nearest Noble gas).

Chemical Periodicity

Read your text chapter on Periodicity. General properties of elements as exemplified on Periodic Table (which are most likely to lose electrons? gain them? across a period? within a group?). What charges do ions for groups I, II & VIIA usually have? ions for Al, O and S? (Remember our model for predicting ionic charges for elements: Group number for Representative metals, Group number -8 for non-metals.) Where are metals located on the Periodic Table? non-metals? semi-metals (metalloids)? What are the formulas of the various gaseous elements, including the various halogens? Which elements occur as liquids at room temperature? Gases? What are allotropes of C (graphite and diamond)?

Moles and Stoichiometry

What is a mole? (One mole = number of atoms in exactly 12 grams of 12C = 6.02 x 1023 particles). What is a formula unit? What is the mass of one atom in grams? (Atomic mass in g/Avogadro's number.) What is the mass of one amu? What is stoichiometry? Be able to solve problems involving stoichiometric relationships (ratios) in chemical reactions. Be able to find formula weights of compounds. Be able to solve mole problems such as we have seen in class; How many moles in _ ? How many atoms of _ in _ ? How many molecules of _ in _ ? How many grams of _ in _ ? etc.) Practice problems are available in the Stoichiometry-Moles Supplemental Study Module. Be able to solve concentration and dilution problems. Be able to find formula weights of compounds. Be able to find % composition of compounds given formulae. Be able to find formulae of compounds given % composition. Be able to find molecular formulae given % composition and MW. Be able to solve problems involving stoichiometric relationships in chemical reaction, in particular Theoretical Yield and Percent Yield problems. Be able to do simple problems involving reactant excess and problems with a limiting reagent. Practice problems are available in the Reaction Stoichiometry Supplemental Study Module.

Chemical Reactions

Be able to balance by inspection simple chemical equations such as we have done in class (What are the products of complete combustion of compounds containing only elements such as C, H and possibly O?). Keep in mind our fundamental assumption that mass is conserved, which is manifested by conservation of atom type and number! A series of examples, including a method to keep track of atoms, may be found on my on-line supplements, Balancing etc. module. Note that these examples do NOT represent reactions in solution, so do not involve net ionic equations!

Be able to write and balance net ionic equations! Keep in mind the charges on ions! (Net Ionic Equations module)For elemental ions look at the Roman Numeral Group number for a first guess (Group I = +1, etc. Group VII = 7-8 = -1 etc.). For transition metals and molecular (polyatomic) ions look at the on-line Table of Common Ions. Be familiar with classification scheme for reactions (text). Know solubility rules for common ions (those on our lists in lecture 11). Keep in mind that most ions in formulae are independent unless you know otherwise. Thus CaCl2 consists of one Ca2+ ion and two Cl1- ions NOT one Cl22- ion!

Thermochemistry

Understand/define exothermic and endothermic. What are exothermic and endothermic reactions. What is heat? work? energy? enthalpy? deltaE = q + w. deltaH= deltaE - w. When are enthalpy and energy equal? Be able to solve heat capacity problems, calorimeter problems. Understand thermochemical equations (what happens to deltaH if the reaction is rewritten in reverse? What is a formation reaction?

Metric (SI) System

What are the base units for metric system system (SI)? How was the meter originally determined? (historically).

Memorize: 2.54 cm = one inch, exactly; prefixes in metric system we discussed (mega-, kilo-, deci-, centi-, milli-, micro-, nano-.) Names/symbols of elements in Table above; Names/formulae of ions in Table of Common Ions and acids in Table of common acids; Avogadro's number = 6.022 x 1023 particles/mole = number of amu's/gram. Mass of one amu in grams (one gram divided by Avogadro's number); solubility rules

You will be provided with a Periodic Chart and all math fomulae needed for exam.


 

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© R Paselk

Last modified 15 November 2009