What is the molecular formula for water?

The enthalpy of formation of water is -285.8 kj/mol. what can be inferred from this statement?

Which part of a feedback mechanism is able to monitor the conditions outside of cells and usually uses nerve cells to relay this information to an intergrating center

According to each substances heat of fusion, which of the items below requires more heat to be added per gram of substance to go from solid to liquid? silver sulfur water lead