Problem 39 - Chemistry: The Central Science

Question

Complete and balance the following molecular equations, and then write the net ionic equation for each: (a) \(\mathrm{HBr}(a q)+\mathrm{Ca}(\mathrm{OH})_{2}(a q) \longrightarrow\) (b) \(\mathrm{Cu}(\mathrm{OH})_{2}(s)+\mathrm{HClO}_{4}(a q) \longrightarrow\) (c) \(\mathrm{Al}(\mathrm{OH})_{3}(s)+\mathrm{HNO}_{3}(a q) \longrightarrow\)

Step-by-Step Solution

Answer

The short answers for each part of the exercise are as follows: (a) The net ionic equation is: \(2H^{+}(aq) + 2OH^{-}(aq) \rightarrow 2H_{2}O(l)\) (b) The net ionic equation is: \(Cu(OH)_{2}(s) + 2H^{+}(aq) \rightarrow Cu^{2+}(aq) + 2H_{2}O(l)\) (c) The net ionic equation is: \(Al(OH)_{3}(s) + 3H^{+}(aq) \rightarrow Al^{3+}(aq) + 3H_{2}O(l)\)

Step 1: Predict the products

We have an acid-base reaction (double displacement). To predict the products, we swap the cations of the reactants: Ca²⁺ and 2OH⁻ react with 2H⁺ and Br⁻ to form CaBr₂ and H₂O.

Step 2: Balance the molecular equation

The balanced molecular equation is: 2HBr(aq) + Ca(OH)₂(aq) → CaBr₂(aq) + 2H₂O(l)

Step 3: Write the complete ionic equation

Breaking each compound into its individual ions, we get: 2H⁺(aq) + 2Br⁻(aq) + Ca²⁺(aq) + 2OH⁻(aq) → Ca²⁺(aq) + 2Br⁻(aq) + 2H₂O(l)

Step 4: Write the net ionic equation

Cancel the spectator ions (Ca²⁺ and 2Br⁻) and obtain the net ionic equation: 2H⁺(aq) + 2OH⁻(aq) → 2H₂O(l) (b) Cu(OH)₂(s) + HClO₄(aq) →

Step 1: Predict the products

We have an acid-base reaction with Cu²⁺ and 2OH⁻ reacting with H⁺ and ClO₄⁻ to form Cu(ClO₄)₂ and H₂O.

Step 2: Balance the molecular equation

The balanced molecular equation is: Cu(OH)₂(s) + 2HClO₄(aq) → Cu(ClO₄)₂(aq) + 2H₂O(l)

Step 3: Write the complete ionic equation

Breaking each compound into its individual ions, we get: Cu(OH)₂(s) + 2H⁺(aq) + 2ClO₄⁻(aq) → Cu²⁺(aq) + 2ClO₄⁻(aq) + 2H₂O(l)

Step 4: Write the net ionic equation

Cancel the spectator ions (2ClO₄⁻) and obtain the net ionic equation: Cu(OH)₂(s) + 2H⁺(aq) → Cu²⁺(aq) + 2H₂O(l) (c) Al(OH)₃(s) + HNO₃(aq) →

Step 1: Predict the products

We have an acid-base reaction with Al³⁺ and 3OH⁻ reacting with H⁺ and NO₃⁻ to form Al(NO₃)₃ and H₂O.

Step 2: Balance the molecular equation

The balanced molecular equation is: Al(OH)₃(s) + 3HNO₃(aq) → Al(NO₃)₃(aq) + 3H₂O(l)

Step 3: Write the complete ionic equation

Breaking each compound into its individual ions, we get: Al(OH)₃(s) + 3H⁺(aq) + 3NO₃⁻(aq) → Al³⁺(aq) + 3NO₃⁻(aq) + 3H₂O(l)

Step 4: Write the net ionic equation

Cancel the spectator ions (3NO₃⁻) and obtain the net ionic equation: Al(OH)₃(s) + 3H⁺(aq) → Al³⁺(aq) + 3H₂O(l)