if the zinc is exposed and a penny is dropped into 4.00 grams of hydrochloric acid, will the acid dissolve all of the zinc

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)

Joan writes four numbers on the board in standard form, and then she writes their scientific notation

‘which reaction would most likely require the use of an inert electrode?