What are chemistry students prone to when learning stoichiometry?

A blog I am reading every week is Math Equals Love . Sarah Carter , math and chemistry teacher in Oklahoma, writes in exquisite detail about the things she is trying in her classroom. Every time I read it, I wish she had been one of my math teachers. Sarah loves, and often features, puzzle she is using in her classroom. I, too, love puzzles and that's probably one of the reasons I love her blog. One of the things I loved best about middle school math were those cheesy, punny puzzles when solving a math problem led to a letter that led to an answer to a question involving math. I recently had to miss three days in my classroom, right as my students needed to take a big quiz over stoichiometry (the math of chemical reactions, for non-chemistry teachers), so, inspired by Sarah and middle school math, I created a puzzle for them to do in my absence. The puzzle consists of 24 paper tiles that have a letter in the center. All the tiles also have an answer at the top of the tile. Some o...