GOB Chemistry Exam Review and Study Guide

Exam Review for GOB Chemistry

Introduction

This study guide summarizes key concepts, formulas, and practice questions relevant to a GOB (General, Organic, and Biochemistry) Chemistry college course. It covers material from multiple chapters, focusing on molecular properties, nomenclature, chemical reactions, solution calculations, and periodic table usage. The guide is structured to help students prepare for typical exam questions, including multiple choice, problem-solving, and chemical equation writing.

Molecular Properties and Nomenclature

Types of Chemical Formulas

• Molecular Formula: Shows the actual number of atoms of each element in a molecule (e.g., C2H6).

• Expanded Formula: Displays all atoms and bonds in the molecule.

• Condensed Structural Formula: Groups atoms to show connectivity (e.g., CH3CH2OH).

• Skeletal Formula: Simplified representation showing the carbon backbone and functional groups.

Nomenclature and Polyatomic Ions

• Nomenclature: Systematic naming of chemical compounds using IUPAC rules.

• Polyatomic Ions: Charged species composed of two or more atoms covalently bonded (e.g., SO42-, NO3-).

Functional Groups

• Alcohol: Contains an -OH group.

• Carboxylic Acid: Contains a -COOH group.

• Amine: Contains an -NH2 group.

• Ether: Contains an -O- linkage between two carbon atoms.

Chemical Reactions and Equations

Types of Reactions

• Dehydration: Removal of water from a molecule, often forming an alkene.

• Hydrogenation: Addition of hydrogen to a molecule, typically converting an alkene to an alkane.

• Hydration: Addition of water to a molecule, often converting an alkene to an alcohol.

Reaction Components

• Name of Reaction: Identifies the type of chemical change.

• Reaction Conditions/Catalysts: Specifies temperature, pressure, or catalysts required.

• Name of Starting Material: The reactant(s) before the reaction.

• Name of Product: The compound(s) formed after the reaction.

• Functional Group Changes: Describes how functional groups are transformed during the reaction.

Solution Calculations and Concentrations

Key Concepts

• Molarity (M): Concentration of a solution, defined as moles of solute per liter of solution.

• Mass Percent (% m/m): Ratio of mass of solute to mass of solution, multiplied by 100.

• Volume Percent (% v/v): Ratio of volume of solute to volume of solution, multiplied by 100.

Important Equations

• $M = \frac{\text{mol solute}}{\text{L solution}}$

• $\% m/m = \frac{\text{mass of solute}}{\text{mass of solution}} \times 100$

• $\% v/v = \frac{\text{volume of solute}}{\text{volume of solution}} \times 100$

Gas Laws and Calculations

Combined Gas Law

• $P_1V_1/T_1 = P_2V_2/T_2$

• Boyle's Law: $P_1V_1 = P_2V_2$ (at constant temperature)

• Charles's Law: $V_1/T_1 = V_2/T_2$ (at constant pressure)

• Gay-Lussac's Law: $P_1/T_1 = P_2/T_2$ (at constant volume)

Partial Pressure

• $P_{\text{total}} = P_1 + P_2 + P_3 + \ldots$

Acids, Bases, and pH Calculations

Definitions

• Acid: Substance that donates protons (H+).

• Base: Substance that accepts protons.

• pH: Measure of hydrogen ion concentration; $pH = -\log[H^+]$

• Equilibrium Constant for Water: $K_w = [H_3O^+][OH^-]$

Periodic Table and Element Classification

Periodic Table Overview

• Groups: Vertical columns, elements with similar properties.

• Periods: Horizontal rows, elements with increasing atomic number.

• Metals, Nonmetals, Metalloids: Classified by position and properties.

Molecular Geometry and Bonding

Electron Group Geometry and Molecular Shape

Electron Groups	Electron-Group Geometry	Bonded Atoms	Lone Pairs	Bond Angle	Molecular Shape
2	Linear	2	0	180°	Linear
3	Trigonal Planar	3	0	120°	Trigonal Planar
3	Trigonal Planar	2	1	120°	Bent
4	Tetrahedral	4	0	109°	Tetrahedral
4	Tetrahedral	3	1	109°	Trigonal Pyramidal
4	Tetrahedral	2	2	109°	Bent

Practice Questions and Tables

Sample Calculation Questions

• Calculate the dose of ibuprofen for a pediatric patient based on weight.

• Determine the mass of aspirin needed to make a solution of given molarity.

• Convert temperatures between Celsius and Fahrenheit.

• Calculate the volume of a solution given mass and density.

Chemical Formula and Name Table

Formula	Name
MgCl2	Magnesium chloride
Li3P	Lithium phosphide
NaNO2	Sodium nitrite
Mg3(PO4)2	Magnesium phosphate
CuN	Copper (II) nitride
FeO	Iron (II) oxide
NaNO3	Sodium nitrate
Cu(OH)2	Copper (II) hydroxide

Molecular Geometry Table

Compound	Name	Draw the molecule	Electron pair geometry	Molecular shape	Polar or nonpolar	Most prevalent IMF
SBr2	Sulfur dibromide	See notes	Tetrahedral	Bent	Polar	Dispersion
CCl4	Carbon tetrachloride	See notes	Tetrahedral	Tetrahedral	Nonpolar	Dispersion

Organic Chemistry Reactions

Sample Reaction Types

• Dehydration of 3,5-dimethylcyclohexanol to form an alkene.

• Hydrogenation of 3-bromo-1-hexanol to form an alcohol.

• Hydration of 2,5-difluoro-3-hexene to form an alcohol.

Functional Group Identification

• Identify and label functional groups in organic molecules.

• Locate all chiral carbons and possible hydrogen bonds to water.

Equations and Constants

Key Equations

• $M_1V_1 = M_2V_2$

• $C_1V_1 = C_2V_2$

• $1 \text{ mole gas} = 22.4 \text{ L}$

• $pH = -\log[H^+]$

• $K_w = [H_3O^+][OH^-]$

Periodic Table Reference

The periodic table is essential for identifying elements, their properties, and their placement in chemical reactions. Students should be familiar with group and period trends, as well as the classification of metals, nonmetals, and metalloids.

Additional Info

• Temperature conversion equations and density formula are not required for the exam.

• Students should review all major concepts from chapters 7-10, including Avogadro's number, solution formation, and chemical equilibrium.