Question

Write and balance each of the following equations, and then identify each by type. a. copper + chlorine \(\longrightarrow\) copper (II) chloride b. calcium chlorate \(\longrightarrow\) calcium chloride \(+\) oxygen c. lithium + water \(\longrightarrow\) lithium hydroxide + hydrogen d. lead(I) carbonate \(\longrightarrow\) lead(II) oxide \(+\) carbon dioxide

Short answer

a. Cu + Cl_2 → CuCl_2 (synthesis)b. Ca(ClO_3)_2 → CaCl_2 + 3O_2 (decomposition)c. 2Li + 2H_2O → 2LiOH + H_2 (single replacement)d. PbCO_3 → PbO + CO_2 (decomposition)

Step-by-step solution

- Copper and Chlorine Reaction

Write the unbalanced equation: Cu + Cl_2 → CuCl_2Balance the equation: The equation is already balanced as 1 Cu atom and 2 Cl atoms are on both sides. Identify the reaction type: This is a synthesis reaction.

- Calcium Chlorate Decomposition

Write the unbalanced equation: Ca(ClO_3)_2 → CaCl_2 + O_2Balance the equation: First, balance the calcium: 1 Ca on both sides. Next, balance the chlorine: 2 Cl on each side. Finally, balance the oxygen: 6 O in total on both sides (3 O_2). The balanced equation is: Ca(ClO_3)_2 → CaCl_2 + 3O_2Identify the reaction type: This is a decomposition reaction.

- Lithium and Water Reaction

Write the unbalanced equation: Li + H_2O → LiOH + H_2Balance the equation: Balance lithium and hydrogen: 2Li + 2H_2O → 2LiOH + H_2Identify the reaction type: This is a single replacement reaction.

- Lead(II) Carbonate Decomposition

Write the unbalanced equation: PbCO_3 → PbO + CO_2Balance the equation: The equation is already balanced as 1 Pb atom, 1 C atom, and 3 O atoms are on both sides.Identify the reaction type: This is a decomposition reaction.

Key concepts

synthesis reaction

A synthesis reaction, also known as a combination reaction, is a type of chemical reaction where two or more simple substances combine to form a more complex product. In our example: Cu + Cl_2 → CuCl_2, we see copper (Cu) reacting with chlorine gas (Cl_2) to form copper(II) chloride (CuCl_2). This reaction is straightforward since elements come together to create a compound.

A key point to remember about synthesis reactions is that they often involve exothermic processes where energy is released.

• Simpler substances are reactants
• Produces a more complex compound
• Common in various chemical processes
• Example: 2H_2 + O_2 → 2H_2O

Synthesis reactions can be very useful in industrial applications, such as manufacturing materials or synthesizing chemicals.

decomposition reaction

In decomposition reactions, a single compound breaks down into two or more simpler substances. Take the example of calcium chlorate decomposing: Ca(ClO_3)_2 → CaCl_2 + 3O_2. Here, calcium chlorate separates into calcium chloride (CaCl_2) and oxygen gas (O_2). Notice how the complex compound (calcium chlorate) splits into simpler molecules.

Main traits of decomposition reactions:

• One reactant yields multiple products
• Often require energy input (endothermic)
• Examples: electrolysis, thermal decomposition
• General form: AB → A + B

These reactions are the opposite of synthesis reactions. They're essential in fields like recycling and waste management, where materials are often broken down into simpler substances for reuse or safe disposal.

single replacement reaction

In a single replacement reaction, one element replaces another element in a compound. For example, lithium reacting with water: 2Li + 2H_2O → 2LiOH + H_2. Lithium (Li) replaces one of the hydrogen atoms in water (H_2O), forming lithium hydroxide (LiOH) and hydrogen gas (H_2).

Key characteristics of single replacement reactions:

• One element swaps places with another in a compound
• Common form: A + BC → AC + B
• Often involve metals replacing hydrogen in acids or water
• Example: Zn + 2HCl → ZnCl_2 + H_2

This reaction type is particularly significant in metallurgy and refining processes, where metals need to be separated or purified through such replacements.