In a chemical reaction, a certain compound changes intoanother compound at a rate proportional to the unchanged amount. ifinitially there is 20 grams of the original compound, and there is16 grams after 1 hour, when will 75 percent of the compound bechange

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)

Imagine that you’re getting ready to move to a new city. when people move, they are influenced by push factors and pull factors, and you have many reasons for your move. which of the following factors is an example of a pull factor? a. wanting to move because you’ve found a great new school somewhere new b. needing to move because there are not enough resources in your old hometown c. being forced to move because your old home is gone d. having to move because there are no jobs in your current hometown

Atrain travels 74 kilometers in 3 hours, and then 81 kilometers in 5 hours. what is its average speed?