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Ch.4 - Reactions in Aqueous Solution
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
All textbooksBrown 14th EditionCh.4 - Reactions in Aqueous SolutionProblem 43
Chapter 4, Problem 43

Magnesium carbonate, magnesium oxide, and magnesium hydroxide are all white solids that react with acidic solutions. (a) Write a balanced molecular equation and a net ionic equation for the reaction that occurs when each substance reacts with a hydrochloric acid solution. (b) By observing the reactions in part (a), how could you distinguish any of the three magnesium substances from the other two?

Verified step by step guidance
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Step 1: Write the balanced molecular equation for the reaction of magnesium carbonate (MgCO_3) with hydrochloric acid (HCl). The reaction involves the formation of magnesium chloride (MgCl_2), carbon dioxide (CO_2), and water (H_2O).
Step 2: Write the balanced molecular equation for the reaction of magnesium oxide (MgO) with hydrochloric acid (HCl). The reaction involves the formation of magnesium chloride (MgCl_2) and water (H_2O).
Step 3: Write the balanced molecular equation for the reaction of magnesium hydroxide (Mg(OH)_2) with hydrochloric acid (HCl). The reaction involves the formation of magnesium chloride (MgCl_2) and water (H_2O).
Step 4: Write the net ionic equation for each reaction. For MgCO_3, the net ionic equation involves the carbonate ion (CO_3^{2-}) reacting with hydrogen ions (H^+) to form carbon dioxide (CO_2) and water (H_2O). For MgO and Mg(OH)_2, the net ionic equations involve the oxide ion (O^{2-}) or hydroxide ion (OH^-) reacting with hydrogen ions (H^+) to form water (H_2O).
Step 5: To distinguish between the three magnesium compounds, observe the reactions: MgCO_3 will produce bubbles of CO_2 gas, while MgO and Mg(OH)_2 will not produce gas. This effervescence can be used to identify MgCO_3.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Acid-Base Reactions

Acid-base reactions involve the transfer of protons (H+) between reactants. In this context, hydrochloric acid (HCl) acts as an acid, donating protons to the magnesium compounds, which can be classified as bases. Understanding the nature of these reactions is crucial for writing balanced molecular and net ionic equations, as it helps identify the products formed, such as magnesium chloride and water.
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Balancing Chemical Equations

Balancing chemical equations is essential to ensure that the number of atoms of each element is conserved in a reaction. This involves adjusting coefficients in front of the reactants and products to achieve equality. For the reactions of magnesium carbonate, magnesium oxide, and magnesium hydroxide with hydrochloric acid, balancing the equations will reveal the stoichiometry of the reactants and products, which is necessary for accurate representation of the chemical processes.
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Net Ionic Equations

Net ionic equations focus on the species that actually participate in a chemical reaction, omitting spectator ions that do not change during the reaction. This concept is particularly useful in distinguishing between the different magnesium compounds, as the net ionic equations will highlight the unique ions produced in each reaction with hydrochloric acid. By analyzing these equations, one can identify specific products that indicate the presence of a particular magnesium compound.
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Related Practice
Textbook Question
True or false: (a) If a substance is oxidized, there must be more oxygen in the substance.
Textbook Question

Write balanced molecular and net ionic equations for the following reactions, and identify the gas formed in each: (a) solid cadmium sulfide reacts with an aqueous solution of sulfuric acid (b) solid magnesium carbonate reacts with an aqueous solution of perchloric acid.

Textbook Question

Write the balanced molecular and net ionic equations for each of the following neutralization reactions: (c) Aqueous nitric acid and aqueous ammonia react.

Textbook Question
True or false: (a) Reduction occurs if the oxidation number of an element increases
Textbook Question

Because the oxide ion is basic, metal oxides react readily with acids. (a) Write the net ionic equation for the following reaction: FeO(s) + 2 HClO4(aq) → Fe(ClO4)2(aq) + H2O(l) (b) Based on the equation in part (a), write the net ionic equation for the reaction that occurs between NiO(s) and an aqueous solution of nitric acid.