What gases occur in the same percentages throughout the layers of the atmosphere? /a. oxygen, nitrogen/b. nitrogen, water vapor c. water vapor, oxygen d. all gases are present in equal amounts in earth's atmosphere really need .

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 first element on the periodic table of elements is carbon. a. true b. false

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.