Epsom salt is used in tanning leather and in medicine. It is hydrated magnesium sulfate, MgSO₄ ∙ 7 H₂O. The water of hydration is lost on heating, with the number lost depending on the temperature. Suppose you heat a 1.394-g sample at 100°C and obtain 0.885 g of a partially hydrated sample, MgSO₄ ∙ x H₂O. What is the value of x?