How many atoms are in 17.5g in lead

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)

The clouds are grey and ground is wet. a quantitative b qualitative

Analyze how limestone is weathered and identify the features that are formed as a result of this dissolution