11:39 One of the best offers that a student can get from an experienced prof. I love that he explicitly said this. A lifechanging offer for some. Thanks John. Speechless.
37:10 “Never add water to acid” is such a lie. In HS AP Bio, I added equal parts water to 95% sulfuric acid. The room stank, but nothing happened. The rule is to never add hot water to near-BOILING concentrated acid.
A quick Google shows why, "Why should water never be added to concentrated acid? If you add water to acid, you form an extremely concentrated solution of acid initially and the solution may boil very violently, splashing concentrated acid. If you add acid to water, the solution that forms is very dilute and the small amount of heat released is not enough to vaporize and spatter it. None." Safe Use of Acid Solution - UC Berkeley, EHS
@@mitocw search “ Cody’s lab water and acid” on RU-vid. He actually tried to get a strong reaction, but it is very difficult. Nothing happens for the most part.
It's not just about the reaction. You make a mistake or have an equipment failure and it splashes... which is safer: a concentrated acid splashing or water splashing? This safety tip holds not just for acids but for bases as well.
