Hydrated cobalt chloride has the formula ${CoCl}_2\cdot 6H_{2}O$.

The formula tells us that each mole of hydrated cobalt chloride contains 6 moles of water.

A sample of ${CoCl}_2\cdot 6H_{2}O$ was heated gently until all the water was removed to form anhydrous cobalt chloride, ${CoCl}_2$.

$${CoCl}_2\cdot 6H_{2}O\to {CoCl}_2+6H_{2}O$$

The mass of water formed was 5.4 g.

Calculate the mass of hydrated cobalt chloride that was heated. (relative atomic masses: H = 1.0, O = 16.0; relative formula mass: ${CoCl}_2\cdot 6H_{2}O$ = 238.0)