9th grade science need help ASAP

Read these sentences from the text. near the equator, the tropics receive the most rain on a consistent basis. as a result, the fresh water falling into the ocean decrease the salinity of the surface water in that region. [. .] . . as the salt content of sea water increases, so does its density. what can you infer about how rain affects the density of surface water near the equator?

Which factor is likely to impact the possible number of compounds ?

Estimate the molar mass of the gas that effuses at 1.6 times the effusion rate of carbon dioxide.