In a lab 178.8g of water is separated into hydrogen gas and oxygen gas. The hydrogen gas has a mass of 20.0g. What is the mass of the oxygen gas produced?
Given complete dissociation, I can automatically say that
Of course, we could do this analytically, and write the chemical equation for water decomposition, and then apportion molar quantities:
ALL chemical equations conserve mass. There were approx.
Would the given reaction be exothermic or endothermic? Why??