help creating a puzzle

[living brain donor]

I'm planning a surprise for my wife and kids and am putting together a sort of treasure hunt to get them to the surprise. The hunt will consist of different puzzles that have to be solved in order. Solve puzzle 1 and you get to puzzle 2 and so on. One of my kids is a linguist do some of the puzzles might be some sort of cipher for example. One is a programmer and that seems easy to create a puzzle or two for. One of my daughters is a chemist - currently working on her master's degree. I have no idea how to create a chemistry related puzzle. The puzzle needs to be in the form of an image, or text but it won't have instructions. The answer needs to be one word or one set of characters so it can be entered as a solution in a url in order to get to the next puzzle. I thought for example of showing an image of the chemical structure for monosodium glutomate and the answer would be MSG. But that seemed to lack creativity. Also, for all I know, something like that is really easy to figure out. I don't want it to be super easy or super hard. If you have any ideas I would love to hear them. Thanks! 

[hypervalent_iodine]

What sort of chemistry does she do? You may like to look at CiSRA and the puzzle competition they used to run. There’s an archive of all their puzzles and solutions, all of which boil down to one word answers. They are very good, and your kids may get a kick out of some of them.