How do u study for a subject that you didn’t understand from the beginning of the year !!! (The subject is chem btw )

I would usually try my BEST to get help from yt videos. I recommend using yt that give the most kindergarten type speaking technique, this is really weird to say but it helps just incase you can be stressed out about the words being given by teachers in Chemistry. And I recommend writing down the notes when they explain as well. Hope this helps!

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

a corroding iron, if that's one of your choices