Separating a compound like H2O by electrolytes is that a chemical or physical change?

In numbering carbon atoms in the parent chain of a hydrocarbon, why would you number from right to left, rather than left to right

Which of the following natural processes is most likely to support the formation of an underwater sinkhole? a pollution buildup from deposited minerals b limestone cave collapsing due to changes in sea level c erosion of large amounts of sand moved by ocean waves d oxidation of rock formed by chemical weathering

How many grams of ammonia would be produced by the decomposition of 16.93 mlof hydrazine? (the density of hydrazine is 1.021g/ml)