License & Usage

Free for teaching. Voluntary support welcome.

RealOChem is built to be used and shared. Students and instructors can use everything here for free. The only thing that needs a paid license is commercial use — for example, a textbook or other product, sold for profit, that embeds or depends on this material.

Content — free for teaching & study

The educational content of RealOChem (practice problems, explanations, hints, instructional text, and answer keys) is licensed under Creative Commons Attribution–NonCommercial 4.0 (CC BY-NC 4.0). In plain terms, you are free to use, copy, and adapt it, as long as you:

• Give credit (BY) — cite “RealOChem” and link back to realochem.com.
• Keep it non-commercial (NC) — no use for commercial advantage without a license (see below).

Classroom and individual study use is non-commercial and welcome at no cost. You do not need to ask permission or pay anything to use RealOChem with your students or for your own learning.

Commercial & textbook use

Using RealOChem content in a product offered for sale — a textbook, course pack, app, or other commercial offering that embeds or depends on it — falls outside the free license and requires a separate commercial license. I’m glad to work something out; please get in touch at realochem@gmail.com.

Just want to chip in?

Individuals and students who’d simply like to say thanks can use the tip jar. It’s a voluntary donation — entirely optional, and never required to use RealOChem.

Code — all rights reserved

The site’s source code is a separate matter from the content above (Creative Commons licenses aren’t meant for software). The code is © 2026 Dennis Cao, all rights reserved.

The RealOChem name

“RealOChem” and the RealOChem logo are reserved trademarks. No license above grants the right to use the name or brand — so nothing built on this material may present itself as RealOChem.