There are 2 molecules of water and 4 molecules of methane. how many moles of methane are there

How many atoms of oxygen are contained in 160 grams of n2o3

Several kinds of bears are found on earth. most bears are brown or black, but one type of bear, the polar bear, is white. what process led to this difference in fur color? explain your answer.

You have 125g of a certain seasoning and are told that it contains 76.0 g of salt what is the percentage of salt by mass in this seasoning