What is the boiling point of methanol? What is the molecular weight of ferrocene? How hot can I heat hexane before the flash point?
These are all questions that are answered using chemical reference sources. These sources vary, they can be dictionaries, encyclopedias, databases, spreadsheets, charts, etc. You may be thinking, why should I use one of these resources? I can just look it up in Wikipedia.
But the problem is, chemistry can be quite dangerous. Do you trust 100 percent the values and statistics on Wikipedia? Especially if you are looking up a boiling point, flash point, or toxicity information? This is why chemical dictionaries and other reference sources exist to provide reliable information that you do not have to second guess.
You may have been asked to use one of the various resources listed to the left in a previous course (general or organic chemistry). Refer to the questions listed in your assignment and answer them by using one or more of the resources to the left. Not all of these resources cover the same material; you may have to try a different source if you cannot find your answer in the first one.