Which occurs more often on earth? physical or chemical changes?

If 90.0 grams of ethane reacted with excess chlorine, how many grams of dicarbon hexachloride would form

Based on its chemical properties, identify the position of each chemical family on the periodic table.

A5.000 g sample of niso4 h2o decomposed to give 2.755 g of anhydrous niso4. what is the formula of the hydrate? what is the full chemical name for the hydrate? what is the molar mass of the hydrate? niso4•_h2o what is the mass % of water in the hydrate?