What is the molecular structure of water? what are the physical and chemical properties of water?

How many moles is 14.5 cm^3 of platinum? the density of platinum is 21.45 g/cm^3.

If a gas has an initial pressure of 101kpa and a volume of 10l, then it expands to a volume of 20l, what is the new pressure?

Suppose that some of the compound spilled out of the crucible after it was heated. would that cause the percent by mass of water in the compound determined by the experiment to be too low, too high, or unchanged? briefly explain your answer.