Predict (and give balanced equations for) the reactions between each of these oxides and water: (a) \(\mathrm{Li}_{2} \mathrm{O},\) (b) \(\mathrm{CaO}\) (c) \(\mathrm{CO}_{2}\).

Balancing chemical equations is a fundamental skill required to understand the quantitative relationships in a chemical reaction. Here's how to think about it:

Every chemical equation represents a recipe for a chemical reaction. The reactants (ingredients) on the left side must result in products (the finished dish) on the right. However, according to the Law of Conservation of Mass, matter cannot be created or destroyed; thus, you must have the same number of each type of atom on both sides of the equation.

When balancing equations, consider the following steps:

• Write down the unbalanced equation.
• List the number of each type of atom present in the unbalanced equation.
• Adjust coefficients (the numbers in front of the compounds) to balance the atoms. Begin with one element and move systematically through the equation.
• Ensure that the coefficients are the smallest possible whole numbers that balance the atoms.
• Double-check your work to confirm that the mass is balanced on both sides.

For example, in the reaction of calcium oxide with water (\(\mathrm{CaO} + \mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{Ca(OH)}_{2}\)), we initially have one calcium atom, one oxygen atom from calcium oxide, and two hydrogen and one oxygen from water on the reactant side. To balance this, we need to ensure that we have the same number and type of atoms on the product side, which is achieved by the balanced equation presented.

Basic oxides, also known as alkaline oxides, are oxides that react with water to form hydroxides. These oxides are typically formed from the metals in the first two groups of the periodic table (s-block elements), such as lithium and calcium in our examples.

When a basic oxide reacts with water, the reaction produces a hydroxide, which is an ionic compound consisting of metal cations and hydroxide anions (\(\mathrm{OH}^{-}\)). Here are some vital points to understand about the reaction of basic oxides with water:

• They usually dissolve in water and increase the pH, making the solution alkaline.
• The general reaction can be written as \(\mathrm{Metal Oxide} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{Metal} \mathrm{Hydroxide}\).
• The reactivity of the metal determines how violently or gently the reaction proceeds.

For example, the reaction of lithium oxide (\(\mathrm{Li}_{2} \mathrm{O}\)) with water is: \(\mathrm{Li}_{2} \mathrm{O} + \mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{LiOH}\), resulting in the formation of lithium hydroxide. It's important when writing these reactions to consider solubility, as not all hydroxides are soluble in water.

Acidic oxides are oxides that react with water to form an acidic solution. These oxides are typically nonmetals or metals in high oxidation states. One prevalent example is \(\mathrm{CO}_{2}\) (carbon dioxide), which reacts with water to form \(\mathrm{H}_2\mathrm{CO}_{3}\) (carbonic acid), as outlined in the exercise.

When acidic oxides dissolve in water, they can partially ionize to form weak acids or completely ionize to form strong acids, resulting in a decrease in pH. The key features of this reaction are as follows:

• Acidic oxides are also known as acid anhydrides because they can be considered dehydrated forms of acids.
• Their general reaction with water can be written as \(\mathrm{Nonmetal Oxide} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{Weak} \mathrm{Acid}\).
• The resulting acids have a higher hydrogen ion concentration in the solution, rendering the solution acidic.

To illustrate, let's discuss the reaction provided in the exercise:\(\mathrm{CO}_{2} + \mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{H}_2\mathrm{CO}_{3}\). Here, carbon dioxide, which is a common acidic oxide, reacts with water to form carbonic acid, a weak acid that partially dissociates in solution. This type of reaction is crucial in natural processes like the carbon cycle and has implications for environmental phenomena such as acid rain.