Question

Azurite is a copper-containing mineral that often forms beautiful crystals. Its formula is \(\mathrm{Cu}_{3}\left(\mathrm{CO}_{3}\right)_{2}(\mathrm{OH})_{2} .\) Write a balanced equation for the reaction of this mineral with hydrochloric acid.

Short answer

The balanced equation is \(\mathrm{Cu}_3(\mathrm{CO}_3)_2(\mathrm{OH})_2 + 6\, \mathrm{HCl} \rightarrow 3\, \mathrm{CuCl}_2 + 2\, \mathrm{CO}_2 + 2\, \mathrm{H}_2\mathrm{O}\).

Step-by-step solution

Write the Formula for the Reactants

The mineral Azurite is represented by \(\mathrm{Cu}_3(\mathrm{CO}_3)_2(\mathrm{OH})_2\) and it reacts with hydrochloric acid, \(\mathrm{HCl}\).

Identify the Products

When azurite reacts with hydrochloric acid, copper(II) chloride \(\mathrm{CuCl}_2\), carbon dioxide \(\mathrm{CO}_2\), and water \(\mathrm{H}_2\mathrm{O}\) are formed.

Write the Unbalanced Equation

The unbalanced chemical equation is: \[\mathrm{Cu}_3(\mathrm{CO}_3)_2(\mathrm{OH})_2 + \mathrm{HCl} \rightarrow \mathrm{CuCl}_2 + \mathrm{CO}_2 + \mathrm{H}_2\mathrm{O}\]

Balance the Equation for Copper Atoms

Azurite contains 3 copper atoms, so we need 3 \(\mathrm{CuCl}_2\) on the product side. The equation becomes: \[\mathrm{Cu}_3(\mathrm{CO}_3)_2(\mathrm{OH})_2 + \mathrm{HCl} \rightarrow 3\, \mathrm{CuCl}_2 + \mathrm{CO}_2 + \mathrm{H}_2\mathrm{O}\]

Balance the Carbon Atoms

There are 2 \(\mathrm{CO}_3\) groups in azurite, leading to 2 \(\mathrm{CO}_2\) molecules on the product side. The equation is now: \[\mathrm{Cu}_3(\mathrm{CO}_3)_2(\mathrm{OH})_2 + \mathrm{HCl} \rightarrow 3\, \mathrm{CuCl}_2 + 2\, \mathrm{CO}_2 + \mathrm{H}_2\mathrm{O}\]

Balance the Hydrogen and Oxygen Atoms

Azurite has 2 hydroxide groups, so it produces 2 water molecules: \[\mathrm{Cu}_3(\mathrm{CO}_3)_2(\mathrm{OH})_2 + \mathrm{HCl} \rightarrow 3\, \mathrm{CuCl}_2 + 2\, \mathrm{CO}_2 + 2\, \mathrm{H}_2\mathrm{O}\]

Balance the Chlorine Atoms

Since there are 3 \(\mathrm{CuCl}_2\) molecules, we need 6 chlorine atoms, thus 6 \(\mathrm{HCl}\). The balanced equation is: \[\mathrm{Cu}_3(\mathrm{CO}_3)_2(\mathrm{OH})_2 + 6\, \mathrm{HCl} \rightarrow 3\, \mathrm{CuCl}_2 + 2\, \mathrm{CO}_2 + 2\, \mathrm{H}_2\mathrm{O}\]

Key concepts

copper-containing mineral

Azurite is a fascinating mineral that captures the eye with its deep blue color. It is a copper-containing mineral, which means it has copper atoms in its chemical structure. Its formula is \( \mathrm{Cu}_3(\mathrm{CO}_3)_2(\mathrm{OH})_2 \). This formula tells us that each molecule of azurite contains three copper atoms, two carbonate groups (\(\mathrm{CO}_3\)), and two hydroxide groups (\(\mathrm{OH}\)). These components interact in specific ways when they undergo a chemical reaction, especially with substances like acids.

Azurite is not only valued for its beauty but also provides a practical source of copper, which is used in various industries. Understanding how it reacts with other chemicals is crucial in extracting copper from the mineral.

hydrochloric acid reaction

When azurite reacts with hydrochloric acid (\(\mathrm{HCl}\)), this reaction is a classic example of a mineral reacting with an acid. Hydrochloric acid is a strong acid, often used in chemical reactions to dissolve mineral compounds.

In the reaction with azurite, the aim is to separate the copper from the other constituents of the mineral. The strong acidity of \(\mathrm{HCl}\) allows it to break down azurite into simpler substances. The chemical reaction involves transforming the components of azurite and \(\mathrm{HCl}\) into new products, including copper compounds. This process is essential in mineral processing to extract valuable metals.

product formation

Product formation in a chemical reaction describes the new substances that are produced from the reactants. For the reaction between azurite and hydrochloric acid, the products include copper(II) chloride (\(\mathrm{CuCl}_2\)), carbon dioxide (\(\mathrm{CO}_2\)), and water (\(\mathrm{H}_2\mathrm{O}\)).

The formation of \(\mathrm{CuCl}_2\) is particularly important, as it contains the copper extracted from azurite, now in a usable form. \(\mathrm{CO}_2\) and \(\mathrm{H}_2\mathrm{O}\) are typically byproducts of reactions between carbonates and acids, where the carbonate usually results in carbon dioxide release. Understanding these products helps chemists predict and control the outcomes of chemical reactions.

atom balancing

Atom balancing is a crucial step in writing chemical equations. It ensures that the number of each type of atom is the same on both sides of the equation, preserving the law of conservation of mass. In our reaction between azurite and hydrochloric acid, it starts with unbalanced numbers of atoms.

To balance this equation:

• We first balance the copper atoms: since we start with 3 copper atoms in azurite, we need 3 \(\mathrm{CuCl}_2\) molecules.
• Next, we balance the carbon atoms, requiring 2 \(\mathrm{CO}_2\) molecules.
• Then, we address the hydrogen and oxygen atoms that come from the hydroxide groups, resulting in 2 \(\mathrm{H}_2\mathrm{O}\) molecules.
• Finally, we balance the chlorine atoms, needing 6 \(\mathrm{HCl}\) molecules to account for the 6 chlorine atoms used in the \(\mathrm{CuCl}_2\).

By following these steps, the balanced chemical equation is achieved, ensuring accurate representation of the reaction.