Problem 16 - Chemistry: Principles and Reactions

Question

Write a balanced equation and give the names of the products for the reaction of (a) sodium peroxide and water. (b) calcium and oxygen. (c) rubidium and oxygen. (d) strontium hydride and water.

Step-by-Step Solution

Answer

Short Answer: (a) The balanced equation for the reaction between sodium peroxide and water is 2Na2O2 + 2H2O -> 4NaOH + O2. The products formed are sodium hydroxide and oxygen. (b) The balanced equation for the reaction between calcium and oxygen is 2Ca + O2 -> 2CaO. The product formed is calcium oxide. (c) The balanced equation for the reaction between rubidium and oxygen is 4Rb + O2 -> 2Rb2O. The product formed is rubidium oxide. (d) The balanced equation for the reaction between strontium hydride and water is SrH2 + 2H2O -> Sr(OH)2 + 2H2. The products formed are strontium hydroxide and hydrogen.

Step 1: Write the unbalanced equation

Write the formulas of sodium peroxide (Na2O2) and water (H2O), and form an unbalanced equation: Na2O2 + H2O -> ?

Step 2: Predict the products

Sodium will react with hydroxide ions from the water to form sodium hydroxide (NaOH) and oxygen gas (O2) will be released, giving us this unbalanced equation: Na2O2 + H2O -> NaOH + O2.

Step 3: Balance the equation

Balance the number of atoms of each element on both sides of the equation: 2Na2O2 + 2H2O -> 4NaOH + O2 The balanced equation is: 2Na2O2 + 2H2O -> 4NaOH + O2 The product names are sodium hydroxide and oxygen. #(b) Calcium and oxygen#

Step 1: Write the unbalanced equation

Write the formulas of calcium (Ca) and oxygen (O2), and form an unbalanced equation: Ca + O2 -> ?

Step 2: Predict the product

Calcium reacts with oxygen to form calcium oxide (CaO): Ca + O2 -> CaO.

Step 3: Balance the equation

Balance the number of atoms for each element on both sides: 2Ca + O2 -> 2CaO The balanced equation is: 2Ca + O2 -> 2CaO The product name is calcium oxide. #(c) Rubidium and oxygen#

Step 1: Write the unbalanced equation

Write the formulas of rubidium (Rb) and oxygen (O2), and form an unbalanced equation: Rb + O2 -> ?

Step 2: Predict the product

Rubidium reacts with oxygen to form rubidium oxide (Rb2O): Rb + O2 -> Rb2O.

Step 3: Balance the equation

Balance the number of atoms of each element on both sides of the equation: 4Rb + O2 -> 2Rb2O The balanced equation is: 4Rb + O2 -> 2Rb2O The product name is rubidium oxide. #(d) Strontium hydride and water#

Step 1: Write the unbalanced equation

Write the formulas of strontium hydride (SrH2) and water (H2O), and form an unbalanced equation: SrH2 + H2O -> ?

Step 2: Predict the products

Strontium hydride reacts with water to form strontium hydroxide (Sr(OH)2) and hydrogen gas (H2): SrH2 + H2O -> Sr(OH)2 + H2.

Step 3: Balance the equation

Balance the number of atoms of each element on both sides of the equation: SrH2 + 2H2O -> Sr(OH)2 + 2H2 The balanced equation is: SrH2 + 2H2O -> Sr(OH)2 + 2H2 The product names are strontium hydroxide and hydrogen.

Key Concepts

Balancing Equations

Balancing chemical equations is a crucial step in understanding chemical reactions. It ensures that the same number of atoms for each element is present on both sides of the equation. Basically, it maintains the law of conservation of mass, which states that matter cannot be created or destroyed. To balance an equation:

• Start by writing the unbalanced equation with the correct chemical formulas for reactants and products.
• Count the number of atoms for each element in both reactants and products.
• Add coefficients in front of the chemical formulas to balance the atoms. This might take a few adjustments.
• Repeat the process until all elements are balanced.

For example, balancing the reaction between sodium peroxide and water involves ensuring equal numbers of Na, O, and H atoms on both sides. The final balanced equation is:\[2\text{Na}_2\text{O}_2 + 2\text{H}_2\text{O} \rightarrow 4\text{NaOH} + \text{O}_2\] Here, the balancing is achieved by adding coefficients to sodium peroxide and water, resulting in sodium hydroxide and oxygen as products.

Sodium Peroxide

Sodium peroxide (\[\text{Na}_2\text{O}_2\]) is an inorganic compound known for its strong oxidizing properties. It reacts with water to release oxygen gas, which can be utilized in various chemical processes such as bleaching, disinfecting, and in breathing devices in submarines or space shuttles. Sodium peroxide can form sodium hydroxide and oxygen when it reacts with water, as shown in the equation:\[2\text{Na}_2\text{O}_2 + 2\text{H}_2\text{O} \rightarrow 4\text{NaOH} + \text{O}_2\]

• Sodium peroxide appears as a yellowish powder and should be handled with care due to its reactivity.
• Its oxidative nature makes it a useful compound in many industrial applications.

Understanding its reaction with water not only helps in balancing chemical equations but also provides insight into its practical applications.

Products of Reactions

In chemical reactions, products are the new substances formed when reactants undergo a chemical change. Understanding what products will result from a given reaction is crucial in predicting chemical behavior and applications. Each type of reaction has characteristic products:

• Combustion reactions typically produce carbon dioxide and water.
• Neutralization reactions between acids and bases produce a salt and water.
• Metal oxides form when metals react with oxygen.

When sodium peroxide reacts with water, the products are sodium hydroxide (\[\text{NaOH}\]) and oxygen gas (\[\text{O}_2\]). Understanding these products allows chemists to predict the possible uses and effects of chemical reactions. Properly predicting and naming products enables chemists to design reactions that achieve desired results.

Calcium Oxide

Calcium oxide (\[\text{CaO}\]), commonly known as lime or quicklime, is an important chemical compound obtained by heating limestone. It is essential in many industrial processes and chemical reactions. When calcium reacts with oxygen, it forms calcium oxide. The balanced equation is:\[2\text{Ca} + \text{O}_2 \rightarrow 2\text{CaO}\]

• Calcium oxide is a white, caustic, alkaline crystalline solid.
• It is used in cement and mortar, as a refractory material in industries, and in the treatment of drinking water.
• It is a basic oxide and will react with acids to form salts.

Recognizing calcium oxide's role and formation highlights its value in both everyday applications and specialized industrial processes, emphasizing the importance of balancing chemical equations to accurately predict product formation.