About the Authors Mark Kernion, M.A.  taught AP, Honors, and Academic Chemistry for 33 years at Mt. Lebanon High School in Pittsburgh, Pennsylvania and currently teaches an online AP Chemistry course through PA Homeschoolers and Chemistry-Prep.com. He received the Yale Teaching Award in 2007, was inducted into the Cum Laude Society (which is dedicated to honoring scholastic achievement in secondary schools) in 2006, and holds a number of patents related to his research. Joe Mascetta, M.S., C.A.S. taught high school chemistry for 20 years. He also served as the science department coordinator and principal of Mt. Lebanon High School in Pittsburgh, Pennsylvania, a science consultant to the area schools, and past-president of the Western Pennsylvania Association of Supervision and Curriculum Development (ASCD) and the State Advisory Committee of ASCD.  About the Publisher In the 1930s, Manuel H. Barron opened a bookstore in Brooklyn, New York.  People from the community asked Mr. Barron about books that might be available to help their children study for the New York State Regents exams. After realizing there wasn't anything available, Mr. Barron created his own study guides. 80 years later, Barron's has helped millions of people prepare for their next step.