Question

Commercial cold packs and hot packs are available for treating athletic injuries. Both types contain a pouch of water and a dry chemical. When the pack is struck, the pouch of water breaks, dissolving the chemical, and the solution becomes either hot or cold. Many hot packs use magnesium sulfate, and many cold packs use ammonium nitrate. Write reactions to show how these strong electrolytes break apart when they dissolve in water.

Short answer

Magnesium sulfate (\(MgSO_4\)) dissociates in water as follows: \(MgSO_4 (aq) \rightarrow Mg^{2+} (aq) + SO_4^{2-} (aq)\). Ammonium nitrate (\(NH_4NO_3\)) dissociates in water as follows: \(NH_4NO_3 (aq) \rightarrow NH_4^{+} (aq) + NO_3^{-} (aq)\).

Step-by-step solution

Identify the magnesium sulfate formula

Magnesium sulfate is an ionic compound with the chemical formula \( MgSO_4 \). Step 2: Dissociation of magnesium sulfate in water

Dissociation of magnesium sulfate in water

When magnesium sulfate dissolves in water, it dissociates into magnesium ions and sulfate ions: \[ MgSO_4 (aq) \rightarrow Mg^{2+} (aq) + SO_4^{2-} (aq) \] For ammonium nitrate: Step 1: Identify the ammonium nitrate formula

Identify the ammonium nitrate formula

Ammonium nitrate is an ionic compound with the chemical formula \( NH_4NO_3 \). Step 2: Dissociation of ammonium nitrate in water

Dissociation of ammonium nitrate in water

When ammonium nitrate dissolves in water, it dissociates into ammonium ions and nitrate ions: \[ NH_4NO_3 (aq) \rightarrow NH_4^{+} (aq) + NO_3^{-} (aq) \] Thus, we have shown the reactions for strong electrolytes, magnesium sulfate and ammonium nitrate, breaking apart when they dissolve in water.