Chapter 15, Problem 50A

Interpretation Introduction

Interpretation: The equation for the change of Epsom salt to its monohydrate form at $150{}^{\text{o}}\text{C}$ needs to be determined.

Concept Introduction: A hydrate is defined as a compound in which water is present in the form of ${\text{H}}_{\text{2}}\text{O}$ molecules with a definite water content by weight. They are generally crystalline solids.

Explanation of Solution

The formula for Epsom salt is ${\text{MgSO}}_{\text{4}}{\text{.7H}}_{\text{2}}\text{O}$ . It is magnesium sulfate heptahydrate. It changes to monohydrate form at $150{}^{\text{o}}\text{C}$ . Here, monohydrate means it contains 1 water molecule. Thus, it results in the release of 6 water molecules. The chemical reaction can be represented as follows:

  ${\text{MgSO}}_{\text{4}}·{\text{7H}}_{\text{2}}\text{O}\stackrel{\Delta ,150{}^{\text{o}}\text{C}}{\to }{\text{MgSO}}_4·{\text{H}}_{\text{2}}\text{O}+6{\text{H}}_{\text{2}}\text{O}$

Therefore, the above reaction shows the formation of monohydrate by heating Epsom salt.