Problem 57 - General Chemistry: Principles and Modern Applications

Question

Sodium nitrite can be made by passing oxygen and nitrogen monoxide gases into an aqueous solution of sodium carbonate. Write a balanced equation for this reaction.

Step-by-Step Solution

Answer

The balanced equation for the reaction is 2O2 + 4NO + Na2CO3 -> 2NaNO2 + CO2.

Step 1: Identify Reactants and Products

Firstly, the reactants are oxygen (O2), nitrogen monoxide (NO), and sodium carbonate (Na2CO3). These react to form Sodium Nitrite (NaNO2) as the needed product.

Step 2: Write Unbalanced Chemical Equation

The unbalanced equation is given as: O2 + NO + Na2CO3 -> NaNO2. This shows the reactants and the product but does not account for the law of conservation of mass yet.

Step 3: Balance The Equation

To balance the equation, coefficients are adjusted before each substance until the same number of each type of atom exists on both the left and the right side of the equation. The balanced equation becomes: 2O2 + 4NO + Na2CO3 -> 2NaNO2 + CO2. This means 2 moles of O2 reacts with 4 moles of NO and 1 mole of Na2CO3 to produce 2 moles of NaNO2 and 1 mole of CO2.

Key Concepts

Sodium Nitrite

Sodium nitrite is an inorganic salt with the chemical formula \( \text{NaNO}_2 \). It appears as a white to slightly yellowish crystalline powder. Sodium nitrite is highly soluble in water and serves a number of purposes, most commonly in the food industry and in chemical manufacturing processes.

In this particular reaction, sodium nitrite is formed by the interaction between sodium carbonate, oxygen, and nitrogen monoxide. It should be noted that sodium nitrite is often used as a preservative in food, most notably in processed meats, due to its ability to inhibit bacterial growth.

Additionally, sodium nitrite is utilized in the creation of dyes and as an intermediate in organic synthesis. Its importance lies in its versatility and its efficacy in preventing the growth of harmful microorganisms. Understanding the production and use of this compound can be highly beneficial for students studying chemistry.

Chemical Reactions

Chemical reactions occur when substances, known as reactants, undergo a process of rearrangement to form new substances, known as products. This transformation involves the breaking of old bonds and the formation of new ones.

For example, in the reaction involving sodium carbonate, oxygen, and nitrogen monoxide, a chemical transformation takes place that produces sodium nitrite and carbon dioxide. The equation representing this transformation helps us understand the stoichiometry involved, which refers to the quantitative relationships between reactants and products in a chemical reaction.

• The unbalanced chemical equation shows all reactants and products involved, but does not yet satisfy all scientific principles, such as the conservation of mass.


• The balancing process involves adjusting the number of molecules so that both sides of the equation contain equal atoms for each element, ensuring a correctly balanced chemical reaction.

Grasping the fundamental aspects of chemical reactions is crucial for anyone studying chemistry, as it deepens understanding of how various substances interact and transform.

Law of Conservation of Mass

The Law of Conservation of Mass is a fundamental principle in chemistry. It states that mass is neither created nor destroyed in a chemical reaction. This means that the mass of the reactants must equal the mass of the products.

When balancing chemical equations, like the one forming sodium nitrite, the principle of conservation of mass is what guides the process. Each type of atom must be present in the same quantity on both sides of a chemical reaction.

• In our reaction, the balancing process ensures equal numbers of sodium, nitrogen, oxygen, and carbon atoms appear on both sides of the equation.


• This ensures that matter is conserved, as required by the law.

Understanding and applying the Law of Conservation of Mass is essential for correctly balancing chemical equations. It helps students appreciate that chemical reactions are not magical transformations but rather systematic rearrangements of matter that adhere to universal laws.