The melting point of a compound is 1240c. is this compound most likely an ionic or molecular compound?

Asample of silver (with work function ? = 4.52 ev) is exposed to an ultraviolet light source (? = 200 nm), which results in the ejection of photoelectrons. what changes will be observed if: silver is replaced with copper (? = 5.10 ev) more photoelectrons ejected no photoelectrons are emitted fewer photoelectrons ejected more energetic photoelectrons (on average) less energetic photoelectrons (on average)

What happens to energy in an open system?

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