Question

Write a balanced equation for the reaction of aqueous sodium carbonate \(\left(\mathrm{Na}_{2} \mathrm{CO}_{3}\right)\) with aqueous nitric acid \(\left(\mathrm{HNO}_{3}\right)\) to yield \(\mathrm{CO}_{2}, \mathrm{NaNO}_{3},\) and \(\mathrm{H}_{2} \mathrm{O}\).

Short answer

Balanced equation: \( \mathrm{Na}_{2} \mathrm{CO}_{3} + 2\, \mathrm{HNO}_{3} \rightarrow \mathrm{CO}_{2} + 2\, \mathrm{NaNO}_{3} + \mathrm{H}_{2} \mathrm{O} \).

Step-by-step solution

Write the Unbalanced Equation

First, write down the chemical formulas of the reactants and products. The reactants are sodium carbonate \( \left(\mathrm{Na}_{2} \mathrm{CO}_{3}\right) \) and nitric acid \( \left(\mathrm{HNO}_{3}\right) \). The products are carbon dioxide \( \left(\mathrm{CO}_{2}\right) \), sodium nitrate \( \left(\mathrm{NaNO}_{3}\right) \), and water \( \left(\mathrm{H}_{2} \mathrm{O}\right) \). The unbalanced chemical equation is: \[ \mathrm{Na}_{2} \mathrm{CO}_{3} + \mathrm{HNO}_{3} \rightarrow \mathrm{CO}_{2} + \mathrm{NaNO}_{3} + \mathrm{H}_{2} \mathrm{O} \]

Balance Sodium Atoms

Look at the number of sodium atoms on both sides of the equation. There are two sodium atoms in sodium carbonate \( \mathrm{Na}_{2} \mathrm{CO}_{3} \) and one in sodium nitrate \( \mathrm{NaNO}_{3} \). Place a coefficient of 2 in front of \( \mathrm{NaNO}_{3} \) to balance the sodium:\[ \mathrm{Na}_{2} \mathrm{CO}_{3} + \mathrm{HNO}_{3} \rightarrow \mathrm{CO}_{2} + 2\, \mathrm{NaNO}_{3} + \mathrm{H}_{2} \mathrm{O} \]

Balance Nitrogen Atoms

Balance the nitrogen atoms next. There is one nitrogen atom in each \( \mathrm{HNO}_{3} \) and two in the products as you have two each of \( \mathrm{NaNO}_{3} \). Thus, place a coefficient of 2 in front of \( \mathrm{HNO}_{3} \):\[ \mathrm{Na}_{2} \mathrm{CO}_{3} + 2\, \mathrm{HNO}_{3} \rightarrow \mathrm{CO}_{2} + 2\, \mathrm{NaNO}_{3} + \mathrm{H}_{2} \mathrm{O} \]

Balance Hydrogen and Oxygen Atoms

Check for the balance of hydrogen and oxygen atoms. Currently, there are 2 hydrogen atoms and 6 oxygen atoms on the left, and the same number on the right. Therefore, the equation is already balanced for hydrogen and oxygen: - Left: 2 H (from 2 \( \mathrm{HNO}_{3} \)), 6 O (3 from \( \mathrm{Na}_{2} \mathrm{CO}_{3} \) + 6 from 2 \( \mathrm{HNO}_{3} \)).- Right: 2 H from \( \mathrm{H}_{2} \mathrm{O} \), 6 O (2 from \( \mathrm{CO}_{2} \) + 6 from 2 \( \mathrm{NaNO}_{3} \)).Since all elements are balanced, the final balanced equation is:\[ \mathrm{Na}_{2} \mathrm{CO}_{3} + 2\, \mathrm{HNO}_{3} \rightarrow \mathrm{CO}_{2} + 2\, \mathrm{NaNO}_{3} + \mathrm{H}_{2} \mathrm{O} \]

Key concepts

Sodium Carbonate in Chemical Reactions

Sodium carbonate, also known as washing soda or soda ash, is a compound often used for cleaning purposes but also plays a significant role in chemical reactions.
It has the chemical formula \( \mathrm{Na}_{2} \mathrm{CO}_{3} \) and consists of two sodium (Na) atoms, one carbon (C) atom, and three oxygen (O) atoms.

The presence of sodium and carbonate ions makes it a versatile reagent. In aqueous solutions, sodium carbonate dissociates into \( \mathrm{Na}^+ \) and \( \mathrm{CO}_{3}^{2-} \) ions, which participate in various reactions:

• Sodium ions are important in balancing charge in ionic reactions.
• Carbonate ions can act as bases, reacting with acids to form carbon dioxide gas in neutralization reactions.

In the context of balancing equations, being able to predict the formation of products like carbon dioxide from sodium carbonate is key to understanding acid-base reactions.

Understanding Nitric Acid

Nitric acid, denoted by the formula \( \mathrm{HNO}_{3} \), is a strong and common acid used in both laboratory and industrial applications.
It plays a critical role in chemical processes such as nitrate salt production and ore refinement.
Due to its acidity, nitric acid reacts violently with bases and materials such as metals and carbonates.

When nitric acid reacts, it typically yields nitrate ions (\( \mathrm{NO}_{3}^{-} \)) and hydrogen ions (\( \mathrm{H}^+ \)) in solution.
This allows it to effectively participate in neutralization reactions, such as having its hydrogen ions react with carbonate ions from sodium carbonate:

• The hydrogen ions combine with carbonate ions to produce carbon dioxide and water as by-products.
• The nitrate ions pair with other metal ions, forming salts such as sodium nitrate.

Thus, understanding the behavior of nitric acid is fundamental to predicting reaction products and balancing chemical equations.

Formation of Sodium Nitrate

Sodium nitrate, represented by the chemical formula \( \mathrm{NaNO}_{3} \), is an important product in many chemical reactions, especially in agriculture as a nitrogen source.
It is a white, crystalline solid known historically as Chile saltpeter and used extensively in fertilizers and explosives.

In the context of reactions with nitric acid and sodium carbonate, sodium nitrate forms as a result of the combination of sodium ions from the carbonate and nitrate ions from the acid:

• Each sodium ion pairs with a nitrate ion to form sodium nitrate.
• Balancing reactions involving sodium nitrate requires careful attention to sodium and nitrate ions, ensuring stoichiometric ratios are maintained.

Balanced reactions involving sodium nitrate illustrate the compound's role as a stable salt and emphasize the overall importance of neutralization reactions in chemistry.

Carbon Dioxide in Chemical Equilibria

Carbon dioxide (\( \mathrm{CO}_{2} \)) is a colorless gas that is vital to many processes, both industrially and biologically.
It is a common product of the decomposition or combustion of carbon-containing compounds.
In the context of the reaction between sodium carbonate and nitric acid, carbon dioxide is produced as a result of the neutralization process:

• The carbonate ion \( \mathrm{CO}_{3}^{2-} \) reacts with proton donors like nitric acid to release \( \mathrm{CO}_{2} \) gas.
• Its formation is often accompanied by bubbling or effervescence, a common indicator of gas evolution in liquid reactions.

Understanding carbon dioxide's role and its production in chemical reactions helps in achieving the correct balance of equations and underscores the dynamic nature of chemical reactions.