Whitson Gordon explains why Google's browser is such a resource hog.
…it (mostly) does so with reason: your convenience. Most of us have become accustomed to lots of tabs and fast page loading, and the price we pay is measured in gigabytes of RAM. That's not to say Chrome couldn't use some memory optimization—it probably could—but this is likely the future of web browsing.
He provides tips on how to curb its "gluttonous appetite," too. Did you know Chrome has its own task manager? (Menu > Tools > Task Manager) Pick a tab, kill a tab.