So I bought the Chem 1E03 textbook and it's called the General Chemistry Principles and Modern Applications; Custom Edition for McMaster University. Is that the right book as the one prescribed in the course outline?

That was introduced last year too. It's a modified version (less content) than the original book of same title, 10th ed

Originally Posted by Leeoku

That was introduced last year too. It's a modified version (less content) than the original book of same title, 10th ed

would it be better to buy the original version?

For your purposes it doesn't matter. Not sure if life sci uses the custom version also but it's possible they use the full book

Chemistry 1A03/1AA3/1E03 all use the same book. Look on the cover of your book, it should say "chem 1E03" on it. If it does, you should be fine. If you bought it from the bookstore, then it should definitely be the right book. The bookstore is only allowed to sell the most current book and only the book that the professor says that you need.