Problem 49 - Chemistry: The Central Science

Question

Write a balanced equation for each of the following reactions: (a) Sulfur dioxide reacts with water. (b) Solid zinc sulfide reacts with hydrochloric acid. (c) Elemental sulfur reacts with sulfite ion to form thiosulfate. (d) Sulfur trioxide is dissolved in sulfuric acid.

Step-by-Step Solution

Answer

a) SO_2 + H_2O → H_2SO_3 b) ZnS + 2HCl → ZnCl_2 + H_2S c) S + 2SO_3^(2-) → S_2O_3^(2-) d) SO_3 + H_2SO_4 → H_2S_2O_7

Step 1: a) Sulfur dioxide reacts with water.

: Reactants: Sulfur dioxide (SO_2) and water (H_2O) Products: This reaction forms sulfurous acid (H_2SO_3) Balanced equation: SO_2 + H_2O → H_2SO_3

Step 2: b) Solid zinc sulfide reacts with hydrochloric acid.

: Reactants: Solid zinc sulfide (ZnS) and hydrochloric acid (HCl) Products: This reaction forms zinc chloride (ZnCl_2) and hydrogen sulfide gas (H_2S) Balanced equation: ZnS + 2HCl → ZnCl_2 + H_2S

Step 3: c) Elemental sulfur reacts with sulfite ion to form thiosulfate.

: Reactants: Elemental sulfur (S) and sulfite ion (SO_3^(2-)) Products: Thiosulfate ion (S_2O_3^(2-)) Balanced equation: S + 2SO_3^(2-) → S_2O_3^(2-) Note: Since the reaction involves ions, we can also present the equation in an ionic form.

Step 4: d) Sulfur trioxide is dissolved in sulfuric acid.

: Reactants: Sulfur trioxide (SO_3) and sulfuric acid (H_2SO_4) Products: The reaction forms pyrosulfuric acid (H_2S_2O_7), also known as oleum. Balanced equation: SO_3 + H_2SO_4 → H_2S_2O_7

Key Concepts

Chemical Reactions

Chemical reactions are processes where substances change into new substances through the breaking and forming of chemical bonds. During a chemical reaction, reactants are transformed into products. A balanced chemical equation represents this process using symbols and formulas for the materials involved. Balancing equations is crucial because it ensures the law of conservation of mass is followed, meaning that the mass of reactants equals the mass of the products. This can be a complex process involving keeping track of the types of atoms and their count throughout the reaction.

• Identify reactants and products: Determine what substances are beginning the reaction and what is formed at the end.
• Balance the equation: Adjust coefficients to ensure the same number of each type of atom on both sides.
• Check your work: Confirm the balance and that all steps follow chemical laws.

Writing balanced equations helps us understand the quantitative relationships in chemical reactions, aiding in practical applications such as predicting yields and scaling reactions for industrial purposes.

Sulfur Compounds

Sulfur compounds are an essential part of chemistry and can participate in various reactions, as seen in our exercise examples. They can wear many hats, from simple diatomic gases like sulfur dioxide ( SO_2 ) to complex ions like thiosulfate ( S_2O_3^{2-} ). Sulfur compounds can pursue multiple pathways in reactions:

• Take part in redox reactions, as sulfur can change its oxidation state easily.
• Form acids upon reaction with water, such as sulfur dioxide forming sulfurous acid.
• React with bases or acids to form salts and water, known as neutralization reactions.

Understanding the behavior of sulfur compounds is crucial, especially in developing industrial products and environmental applications.

Acid-Base Reactions

Acid-base reactions are transformations involving transfer of protons ( H^+ ) between substances. These reactions are characterized by acids (proton donors) reacting with bases (proton acceptors) leading to the formation of water and a salt. Key points to remember when dealing with these reactions:

• Acids like hydrochloric acid ( HCl ) donate protons to the substances they react with, such as in the reaction with zinc sulfide ( ZnS ).
• Balancing is crucial to ensure stoichiometric relationships, as seen when producing zinc chloride ( ZnCl_2 ) and hydrogen sulfide ( H_2S ).
• Neutralization results in a complete reaction where acids and bases reduce each other's properties, forming neutral products.

Acid-base reactions are foundational in chemistry, underpinning processes from digestion in biology to neutralization of chemical spills in environmental science.

Inorganic Chemistry

Inorganic chemistry deals with the properties and behaviors of inorganic compounds, many of which involve elements other than carbon, or with carbon not belonging to the primary structure. It studies:

• Oxides, sulfides, and other compounds with metals and non-metals, as seen in reactions with sulfur hexafluoride and zinc sulfide.
• The synthesis and reactivity of compounds in categories such as halides, oxides, sulfates, and silicates.
• The study of ions and ionic compounds, which are important in a wide range of industrial and biological processes.

Inorganic chemistry is vital due to its application in creating catalysts, pigments, coatings, surfactants, medicines, and fuels. It provides insights into materials and processes crucial to technological and scientific advancements.