Ova Solving applied mass percent problems Cobalt(II) chloride forms several hydrates with the general formula CoCl2 xH20, where x is an integer. If the hydrate is heated, the water can be driven off, leaving pure CoCl, behind. Suppose a sample of a certain hydrate is heated until all the water is removed, and it's found that the mass of the sample decreases by 12.%. Which hydrate is It? That is, what is x? $ ? Explanation Check