Astudent has a sample of isopropanol (c3h7oh) that has a mass of 78.6 g. the molar mass of isopropanol is 60.1 g/mol. how many moles of isopropanol are contained in this sample?

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)

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Calculate the number of molecules present in 0.750 mol of mgo.