Problem 45 - Chemistry The Molecular Nature of Matter

Question

Write the unbalanced equations for the following reactions: (a) Iron(III) hydroxide reacts with hydrogen chloride forming water and iron(III) chloride. (b) Silver nitrate is reacted with barium chloride to form silver chloride and barium nitrate.

Step-by-Step Solution

Answer

The unbalanced equations are: (a) Fe(OH)3 + HCl → H2O + FeCl3, (b) AgNO3 + BaCl2 → AgCl + Ba(NO3)2.

Step 1: Write the Reactants for Reaction (a)

Identify and write down the chemical formulas of the reactants for the reaction between Iron(III) hydroxide and hydrogen chloride. The formula for Iron(III) hydroxide is Fe(OH)3 and for hydrogen chloride is HCl.

Step 2: Write the Products for Reaction (a)

Determine and write down the chemical formulas of the products for the reaction between Iron(III) hydroxide and hydrogen chloride. The products are water (H2O) and iron(III) chloride (FeCl3).

Step 3: Writing the Unbalanced Equation for Reaction (a)

Combine the reactants and products to write the unbalanced chemical equation: Fe(OH)3 + HCl → H2O + FeCl3.

Step 4: Write the Reactants for Reaction (b)

Identify and write down the chemical formulas of the reactants for the reaction between silver nitrate and barium chloride. The formula for silver nitrate is AgNO3 and for barium chloride is BaCl2.

Step 5: Write the Products for Reaction (b)

Determine and write down the chemical formulas of the products for the reaction between silver nitrate and barium chloride. The products are silver chloride (AgCl) and barium nitrate (Ba(NO3)2).

Step 6: Writing the Unbalanced Equation for Reaction (b)

Combine the reactants and products to write the unbalanced chemical equation: AgNO3 + BaCl2 → AgCl + Ba(NO3)2.

Key Concepts

Chemical Reactions

When studying chemical reactions, we explore the process where substances, known as reactants, transform into new substances, known as products. These changes occur as a result of the breaking and forming of chemical bonds. For example, when iron(III) hydroxide reacts with hydrogen chloride, the atoms in the reactants rearrange, breaking their initial bonds and forming new ones to create water and iron(III) chloride.

It's crucial for students to understand the nature of the reactants and the conditions under which they interact. In educational platforms, focusing on the physical states of the reactants and products, as well as the conservation of mass during the reaction, enriches the learning experience and helps solidify the concept of chemical changes.

Chemical Formula

The chemical formula of a substance provides vital information about its composition, showing the types and numbers of atoms present. For instance, Fe(OH)₃ represents iron(III) hydroxide, indicating that each molecule consists of one iron atom, three oxygen atoms, and three hydrogen atoms, bonded in a specific arrangement.

Understanding how to read and write chemical formulas is a foundational skill in chemistry. Educators can enhance comprehension by breaking down complex formulas into their constituent parts and explaining the significance of subscripts and parentheses, as seen in barium nitrate, Ba(NO₃)₂, which tells us there are two nitrate ions per barium ion.

Balancing Equations

The principle of balancing equations is based on the law of conservation of mass, stating that matter cannot be created or destroyed in a chemical reaction. Essentially, this means that the number of atoms of each element must remain the same before and after the reaction. Take the unbalanced equation for the formation of water and iron(III) chloride: Fe(OH)₃ + HCl → H₂O + FeCl₃.

To balance it, we must ensure that there are equal numbers of each type of atom on both sides of the reaction. This often requires adding coefficients to the chemicals in the equation, which multiplies the number of molecules but not the formula itself. To facilitate learning, breaking down complex reactions into simpler steps and employing visual aids like atom counters can greatly help students in mastering this essential skill in chemistry.