The "Mastering Chemistry" series by Pearson is an e-textbook that requires an access code, credit card or PayPal account for use. Students have the option of receiving the access code when they purchase their textbook or as a standalone access kit. Paying with a PayPal account or credit card gives the student instant access to the material.
The e-textbook offers several types of help for students as they complete the course. For those lacking the skills in math or chemistry to succeed in the college level course, the instructor has the option of assigning a unit at the beginning to help with these basic skills. The assignment allows the student to evaluate his skills and return to improve them as necessary throughout the course.
Professors can post questions for students to access online while in class. The students can then post answers, allowing the instructor to evaluate their understanding of the topic and address specific issues as necessary.
Some instructors may choose to use the tool for homework because it provides instant feedback to the student along with follow-up assignments that address gaps in learning. Along with readings for the student, the e-textbook provides videos that that include assessment tools designed to reinforce the student's learning.