AP Chemistry is unlike the other APs, and many colleges are either only accepting 5s or not accepting AP grades. The problem with AP chem specifically is the expectation. teachers are given a book which has several labs, and they are supposed to go through every lab in the book, one of the labs mentioned in the book will be in the AP exam and no one knows until exam day which one it is. If you do not do the lab then you will most likely not get the entire AP question correct though if you are good you can come up with the answers without having done the lab.
the problem is that there is a time period for those labs, and at least in my schools case, the amount of time which we should supposedly spend on the labs would exceed the amount of time that we will be taking the class through out the year, so we only cover a few of them and hope one of the labs we did are in the exam.
The questions can in some cases get a bit complicated, specifically the multiple choice, unlike other AP exams i have taken, including AP calc (which is a walk in the park compared to AP chem), the questions do not allow a chance of error and there is always one response that is wrong but very close, and its placed in the exam on purpose to trick people. 3 of them can generally be eliminated as wrong responses, and one of the choices is right.
while it is true, a college class can go through the entire book in one semester, the problem in high school one would have about 5 hours per week to cover the entire book, there are 35-40 hours of school per week, giving a time frame of (if one considers 8 hours of sleep) 168 - 56 - 40 = 72 hours of work time. one would generally take from this extracurricular activities as needed, and then whatever time is left over, at least for my school it is divided between 7 classes (some over achievers can have as many as 11 classes), which in general gives over 10 hours per class, per week, however, that will never happen, there are about 8-9 hours during the weekdays to cover classes that fit whichever schedule one has (some schools have block scheduling, other a class the entire day, and some every class the same day every day.), the person would be a apart from civilization and stuck at home if that was attempted.
however, my advice to anyone taking AP chem, is to get AP practice books, read them, study them, practice taking the AP exams that they offer for practice in the time that would generally be given, and do it after each grading period, determine the results, you will with out a doubt fail the first time (if not then hell, deciding not to take the exam would be a crazy idea... lol). make the most of the time.
at this point if i were to do the calculations for my self i would have 62 hours to be divided between 9 classes not counting extracurricular, which includes community service, internships, clubs, projects, and as a senior applications.