Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chemistry 107 - Fall 2008

Exam I Study Guide

Final 2008 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, lanthanide, actinide, s-block element, p-block element, representative element, monatomic, diatomic, cation, anion, binary compounds, periodic table, ionization, ionic compound, formula, polyatomic ion. Orbital. s-orbital, p-orbital. Molecular weight. Formula weight. Empirical formula. Molecular formula. Chemical bond, ionic bond, covalent bond.

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 determine oxidation numbers for any atom in a compound using the rules we have used in class. 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 Chapter 6 of 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:

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). Bohr model for atom. What is wrong with the Bohr model? Geometry (shapes) of s- (spherical) and p- (two lobes along the x, y, or z axis with planar symmetry) orbitals for hydrogen. Be able to write electronic configurations for any of the atoms (and their ions) on the periodic chart using the spectroscopic convention, the inert gas core convention, and/or the orbital diagram convention. 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: ion achieves electronic configuration of nearest Noble gas.) Where are metals located on the Periodic Table? non-metals? semi-metals (metalloids)? Which elements occur naturally in the pure state(e.g. Noble gases; C, O, N, S,, Cu, Ag, Au,)? 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)? How do ionization energy, atomic radii and electronegativity vary on the Periodic chart. Know trends for these properties, elements with highest and lowest values. Which elements are considered to be metals? non-metals? metalloids (semi-metals)?

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.

Bonding

What characterizes a covalent bond? an ionic bond? Predict whether a bond between two atoms is covalent or ionic. Predict the charges of ions of the representative elements. Explain why they have these charges (stable octets). Octet Rule. Valence electrons. Lewis Dot Structures. What does the kernal of a Lewis Structure represent? Be able to write Lewis Structures for atoms, ions, and ionic compounds of the representative elements. (Many solved examples are in PS in lab manual, pg 27ff, but skip part 2v, w, z, & dd and part 3b & c for this exam. Additional examples are available in problem Set A of the Supplemental Study Module) How do you guess whether a compound is likely to be ionic or covalent? (hi, lo, intermediate rules, for electronegativity; or if EN > 1.7 then ionic-Memorize the electronegativities of the Period 2 elements and hydrogen.). Don't forget charges for ions and brackets for negative ions!

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; °C = K-273.16, K = °C+273.16, 1 °C = 1.8 °F. 0 °C = 32 °F, 100 °C = 212 °F, 37 °C = 98.6 °F, 20 °C = 68 °F. Avogadro's number = 6.02 x 10²³ particles/mole = number of amu's/gram. Mass of one amu in grams (one gram divided by Avogadro's number).

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© R Paselk

Last modified 3 October 2008