Here's why:

* Formation of a precipitate: The reaction produces a solid, insoluble product called magnesium chromate (MgCrO₄). This indicates a new substance is being formed, a key characteristic of chemical reactions.

* Exchange of ions: The reaction involves the exchange of ions between the reactants, leading to the formation of new ionic compounds.

Here's the balanced chemical equation for the reaction:

Mg(NO₃)₂ (aq) + K₂CrO₄ (aq) → MgCrO₄ (s) + 2 KNO₃ (aq)

Explanation:

* (aq) indicates that the substance is dissolved in water (aqueous solution).

* (s) indicates that the substance is a solid (precipitate).

In summary: The reaction between magnesium nitrate and potassium chromate is a chemical reaction that results in the formation of a new solid compound, magnesium chromate.