Which of the following landforms is formed by river erosion?

At 450 mm hg a gas has a volume of 760 l, what is its volume at standard pressure

If i add water to oil what will happen

I'm learning about the periodic tables and what each subject's configuration is. for example, hydrogen is 1s^1, but i don't understand how you get that. can someone me understand how to figure out how to figure this out? sorry if the question makes no sense, but it would really a lot if you could me understand! you so much if you can!