NAME (print) _______________________________________ CHEM 343 Organic Chemistry I – Fall 2014 ALL STUDENTS: BRING THIS SHEET TO RECITATION!!! This is a review of concepts from CHEM 142 that will be relevant in organic chemistry. Complete the following review problems using the course text or any other resources available to you. You will work with other students and get help during your CHEM 343 lab recitation. Dr. Brush’s lecture students: This is Problem Set #1 which is due Friday, September 12 at the beginning of class (I will not accept late Problem Sets). You may work together, but each student must turn in their own work. This Problem Set is worth 10 points. (1) Structure. Draw a reasonable Lewis Structure for the following compounds. No rings! Include lone pairs. HCO2H [CH3NH3]+1 (2) Formal Charge of an atom. (a) What do we mean by the formal charge on the atoms in a molecule, and how does formal charge relate to the molecular charge? (b) Assign the proper Formal Charge to each C, N, and O atom in the structure drawn on the right. (3) Hybridization and Molecular Geometry. (a) What is atomic orbital hybridization, and how is this connected to molecular geometry? (b) What do we mean by “sigma” and “pi” covalent bonds? (continued) (c) Complete the following table by indicating the molecular geometry (tetrahedral, bent, linear, trigonal pyramid, trigonal planar) and hybridization (sp, sp2, sp3) of each labeled atom in the molecule below. atom hybridization Molecular geometry (a) C (b) C (c) O (d) C (e) N (d) What is the total number of pi covalent bonds in the molecule above? _____________ (e) Write the formula for this molecule (ex., C3H8O): ___________________________ (f) What is the molecular mass of this molecule (4 sig fig): _________________________ (g) If you had 3.76 g, how many moles would you have? _____________________ (show work below and use correct sig fig): (4) Relationship between Covalent Bonds, Lone Pairs, Geometry and Hybridization for an Atom. Based on the incomplete information given in each row of this table, complete the empty boxes for each atom. This is NOT related to the molecule above! Sigma Covalent Pi Covalent Molecular Atom Lone Pairs Hybridization Bonds Bonds Geometry Carbon 4 0 Carbon 0 0 Carbon 2 0 Oxygen 2 0 2 Nitrogen 3 0 1 trigonal planar sp