Answer:
1.
Explanation:
Let's start with the hydrogen. If we have 4 grams of hydrogen, it would be enough for 4 * 9 = 36 grams of water. Well, that can't be possible ...
4 votes
I think it's hydrogen. Hope this helps :)
2.5X20=50g
50g should be the right answer
Mass=volumeXdenisty.