How many argon atoms are present in 2.0 moles of argon gas?

What substance has a mass of 9.5g and volume of 2.1cm^3

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.

What are the two largest greenhouse gases