Why is tin foil a good insulator

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

Which statement is usually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.

How many atoms are there in 5.70 mol of mg