Good day and thank you for your question, Cheryl.
What you entered in your question I would braille as follows:
⠨⠠⠙⠠⠓⠧⠁⠏⠀⠨⠅⠀⠍⠷⠆⠆⠢⠔⠀⠰⠠⠚⠸⠌⠰⠛⠾
⠨⠠⠙⠠⠓⠋⠥⠎⠀⠨⠅⠀⠍⠷⠒⠒⠲⠀⠰⠠⠚⠸⠌⠰⠛⠾
You said you have examples where ⠸⠙⠠⠓ and ⠨⠠⠓ are used for ΔH (“Delta H”). I do not know why that is.
The document attached in two file formats shows common print presentations of your examples and their corresponding transcriptions in simbraille.
I hope this is helpful.
–Kyle