The term "same chemical reaction" refers to a specific chemical process that occurs when two or more substances interact in such a way as to produce a predictable and measurable outcome. Full definition
Same thing with adding two chemicals; you always get the same chemical reaction. (religion.blogs.cnn.com)
Because all pregnancy tests use the same chemical reaction to test the sample, they are all pretty much the same when it comes to accuracy. (earlymomentsmatter.org)
The study's findings showed that volatile elements undergo the same chemical reactions during extreme temperature and pressure events whether taking place on Earth or in outer space. (sciencedaily.com)