A chemist will prepare a stock solution of HCl so that 27.15 mL stock samples will produce a solution with a concentration of 0.357 M after 741.25 mL of water is added. What should the molarity of the stock solution be?

0.09 moles of sodium sulfate in 12 ml of solution

What is the empirical formula for c4h8o2

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!