How many Hydrogen are in 4H2O?

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)

In a chemical reaction at equilibrium, the rate of the forward reaction the rate of the reverse reaction. if the rate of the forward reaction more products are formed.

If an area has high air pressure and low humidity, what type of weather will it most likely have? plz !