I'd double check that you don't have any Chrome processes still running after you tell it to close / exit, your list does have a lot of 90ish mb entries for only a single (blank?) tab... maybe old ones aren't quitting. And I'd suspect extensions / add-ons too (I'll +1 Yisroel's answer too), try & compare to a new empty profile.
In general, I think the multiple processes is a design decision, and it makes it easier to see what webpages are using cpu/ram - there's (at least one) process for each tab in addition to a few for "general Chrome stuff". But it does really clutter up normal process viewing, especially "top-three" type lists.
Chrome's built-in task manager (shift-esc?) is an easy way to see tab processes & descriptions.
On linux, Chrome/Chromium is similar in showing multiple processes instead of just one like Firefox, but they're both comparable in resource usage. FYI There's a way to see all Firefox's "hidden processes" too so it's similar to Chrome, I don't know how to do that in Windows though.