How do I give a Chemistry set to a non-scientific sim?

There are cheats to unlock all of the career rewards: bb.ignoregameplayunlockentitlements.

If I'm not mistaken, you can also use the bb.showhiddenobjects cheat as well.

Edit to add: I'm pretty sure you can also use them in manage worlds. I used them to build my community center in Oasis Springs.

But if you just need it for robot salvage parts, @Stormkeep's suggestion would probably be easier. Also, fix broken objects (and maybe even upgrading) gives you a couple as well. Unless that's a mod setting.