Q1. For each of the following, write molecular and net ionic equations for any precipitation reaction that occurs. If no reaction occurs, indicate this. a. Zinc chloride and sodium sulfide are dissolved in water.

Background

Topic: Precipitation Reactions and Solubility Rules

This question tests your ability to predict whether a precipitation reaction will occur when two aqueous ionic compounds are mixed, and to write both the molecular and net ionic equations for the reaction. You will need to use solubility rules to determine if any insoluble product (precipitate) forms.

Key Terms and Formulas

• Precipitation Reaction: A reaction in which an insoluble solid (precipitate) forms when two solutions are mixed.

• Molecular Equation: Shows all reactants and products as compounds with their physical states.

• Net Ionic Equation: Shows only the species that actually change during the reaction (removes spectator ions).

• Solubility Rules: Used to determine if a compound is soluble (aq) or insoluble (s) in water.

Step-by-Step Guidance

1. Write the formulas for the two compounds: zinc chloride () and sodium sulfide ().

2. Write the balanced molecular equation for the double displacement (metathesis) reaction between and :

   Switch the cations and anions to form the possible products: and .

3. Use the solubility rules to determine the physical states of the products:

   • Is soluble or insoluble in water?

   • Is soluble or insoluble in water?

4. If a precipitate forms (an insoluble product), write the complete ionic equation by breaking all strong electrolytes (soluble salts) into their ions.

5. Identify and remove the spectator ions to write the net ionic equation. Stop here and check your work before proceeding to the final answer.

Try solving on your own before revealing the answer!