You may take these two online tests as practice tests for Formula Writing and Naming Compounds.
You are not required to print the score report certificates generated by the site at the end of each test. Your scores in these two tests will not be recorded. You are also allowed to take the tests as many times as you like.
Once you get the hang of taking online tests, you may proceed to take the 40-item test discussed here. Make sure that you have read and understood the instructions found on the page before going to the quiz page. You are required to print your score report certificate.
Good luck!