a solution of Ca(OH)2 is mixed with a solution of 30.00 mL of 0.73 M AgNO3. 2.5 grams of solid AgOH precipitate is formed. How many moles of AgOH were precipitated? Use correct significant figures

Earth's axis of rotation is tilted at an angle of 23.5 degrees. what is one change you would see on earth if its axis was not tilted?

What is the molar mass of a gas that has density of 2.054 g/l

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!