Chiming in…
Regarding where to place the code switch indicators, without more context it is not possible to understand which words are math (part of the chemical equation) and which are not.
If these two bulleted items are one after the other as shown in your image, and if all six words are to be transcribed inside the switches, then you can open Nemeth before the first bullet and terminate Nemeth after the last word. Bullets can appear in either UEB context or in Nemeth context without switching.
– Lindy