This activity covers some of the material found in Topic 2 of the Environmental Chemistry module. The information is presented on a series of pages. Most of the pages finish with a quiz in which you must answer questions by clicking on various parts of an image or typing words into a box. The questions are asked in a random order and you must answer them all correctly before you will be allowed to proceed. Each time you make a mistake the quiz will automatically restart. When you complete a quiz you will be given a clearance code which you should note down for later use on the clearance page. At the end of the set of quizzes you should print out a copy of the clearance certificate and hand this in to your teacher as proof that you have completed the activity.