I had a similar test for Gchem, they're really just testing to see if you need to take a pre-general chemistry class, and so they make the test with the assumption that you haven't had chemistry in a few years. The questions should be easy enough that it comes back to you during the test, don't stress, and it's nothing you really need to study for.
English tests are to see that you are a fluent english writer, and are more or less if you can string a few paragraphs togeather to be put in Freshman level english.... and if you took any AP english classes (but didn't pass the AP test I guess), Freshman english is a joke for the most part.
Math tests are also pretty easy if you're ok with math, they keep it basic enough to a point where they ask you questions with material that is introduced in previous classes that you should have taken, for example if you're testing into Calc, they'll ask some basic pre-calc questions to more or less see if you took the class and remember anything.
Placements tests aren't meant to be hard, they're just meant for you to show what classes you've already taken.