Question

Elemental chlorine, \(\mathrm{Cl}_{2}\), is very reactive, combining with most metallic substances. Write a balanced equation for the reaction of each of the following metals with \(\mathrm{Cl}_{2}: \mathrm{Na}, \mathrm{Al}, \mathrm{Zn}, \mathrm{Ca},\) and \(\mathrm{Fe}\).

Short answer

The balanced chemical equations for the reactions of chlorine with the metals are: 1. Sodium: \(2Na + Cl_2 \rightarrow 2NaCl\) 2. Aluminum: \(2Al + 3Cl_2 \rightarrow 2AlCl_3\) 3. Zinc: \(Zn + Cl_2 \rightarrow ZnCl_2\) 4. Calcium: \(Ca + Cl_2 \rightarrow CaCl_2\) 5. Iron: \(2Fe + 3Cl_2 \rightarrow 2FeCl_3\)

Step-by-step solution

Reaction of Sodium with Chlorine

When sodium (Na) reacts with chlorine gas (Cl₂), the product formed is sodium chloride (NaCl). Write the unbalanced equation: \(Na + Cl_2 \rightarrow NaCl\) After balancing the equation, 2 atoms of Na react with 1 chlorine molecule (Cl₂) to form 2 molecules of NaCl: \(2Na + Cl_2 \rightarrow 2NaCl\)

Reaction of Aluminum with Chlorine

When aluminum (Al) reacts with chlorine gas (Cl₂), the product formed is aluminum chloride (AlCl₃). Write the unbalanced equation: \(Al + Cl_2 \rightarrow AlCl_3\) After balancing the equation, 2 atoms of Al react with 3 chlorine molecules (Cl₂) to form 2 units of AlCl₃: \(2Al + 3Cl_2 \rightarrow 2AlCl_3\)

Reaction of Zinc with Chlorine

When zinc (Zn) reacts with chlorine gas (Cl₂), the product formed is zinc chloride (ZnCl₂). Write the unbalanced equation: \(Zn + Cl_2 \rightarrow ZnCl_2\) The equation is already balanced: 1 atom of Zn reacts with 1 chlorine molecule (Cl₂) to form 1 unit of ZnCl₂: \(Zn + Cl_2 \rightarrow ZnCl_2\)

Reaction of Calcium with Chlorine

When calcium (Ca) reacts with chlorine gas (Cl₂), the product formed is calcium chloride (CaCl₂). Write the unbalanced equation: \(Ca + Cl_2 \rightarrow CaCl_2\) The equation is already balanced: 1 atom of Ca reacts with 1 chlorine molecule (Cl₂) to form 1 unit of CaCl₂: \(Ca + Cl_2 \rightarrow CaCl_2\)

Reaction of Iron with Chlorine

When iron (Fe) reacts with chlorine gas (Cl₂), the product formed is iron(III) chloride (FeCl₃). Write the unbalanced equation: \(Fe + Cl_2 \rightarrow FeCl_3\) After balancing the equation, 2 atoms of Fe react with 3 chlorine molecules (Cl₂) to form 2 units of FeCl₃: \(2Fe + 3Cl_2 \rightarrow 2FeCl_3\) In summary, here are the balanced chemical equations for the reactions of chlorine with the metals: 1. Sodium: \(2Na + Cl_2 \rightarrow 2NaCl\) 2. Aluminum: \(2Al + 3Cl_2 \rightarrow 2AlCl_3\) 3. Zinc: \(Zn + Cl_2 \rightarrow ZnCl_2\) 4. Calcium: \(Ca + Cl_2 \rightarrow CaCl_2\) 5. Iron: \(2Fe + 3Cl_2 \rightarrow 2FeCl_3\)

Key concepts

Reaction of Metals with Chlorine

When metals react with chlorine, they form metal chlorides. This process is a type of chemical reaction known as synthesis, where two or more simple substances combine to form a more complex compound.
Elemental chlorine, represented as \ \( \mathrm{Cl}_2 \ \), is a highly reactive halogen that readily reacts with metals. This reactivity is due to chlorine's ability to accept electrons from the metals, leading to the formation of ionic compounds.
For example, sodium (Na) reacts with chlorine gas (\ \( \mathrm{Cl}_2 \ \)) to produce sodium chloride (NaCl), a compound often used as table salt. In this reaction, sodium donates an electron to each chlorine atom, forming \ \( \text{Na}^+ \ \) and \ \( \text{Cl}^- \ \) ions that combine to make NaCl.

• Sodium: \ \( 2\text{Na} + \text{Cl}_2 \rightarrow 2\text{NaCl} \ \)
• Aluminum: \ \( 2\text{Al} + 3\text{Cl}_2 \rightarrow 2\text{AlCl}_3 \ \)
• Zinc: \ \( \text{Zn} + \text{Cl}_2 \rightarrow \text{ZnCl}_2 \ \)
• Calcium: \ \( \text{Ca} + \text{Cl}_2 \rightarrow \text{CaCl}_2 \ \)
• Iron: \ \( 2\text{Fe} + 3\text{Cl}_2 \rightarrow 2\text{FeCl}_3 \ \)

These reactions demonstrate how metals react with chlorine gas to form metal chlorides, each having different stoichiometric coefficients depending on the specific metal involved.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the substances involved in a chemical reaction. It is fundamental for understanding how chemical equations are balanced.
In the context of metal reactions with chlorine, stoichiometry helps determine the exact amounts of metals and chlorine gas needed to produce the corresponding metal chloride without any leftover reactants.
For instance, the balanced reaction for aluminum with chlorine gas is \ \( 2\text{Al} + 3\text{Cl}_2 \rightarrow 2\text{AlCl}_3 \ \). Here, stoichiometry tells us that for every 2 moles of aluminum, 3 moles of chlorine gas are required, which will yield 2 moles of aluminum chloride. This calculation ensures the conservation of mass and atoms through the reaction.

• Requires maintaining equal numbers of each type of atom on both sides of the equation.
• Ensures the conservation of mass, adhering to the Law of Conservation of Mass.

Understanding stoichiometry is essential for balancing chemical equations and predicting the amounts of products formed from given quantities of reactants.

Chemical Reactions

Chemical reactions involve the transformation of reactants into products and are classified into different types such as synthesis, decomposition, single replacement, and double replacement. The reaction of metals with chlorine is an example of a synthesis reaction, where the reactants combine to form a single product, the metal chloride.
During these reactions, bonds between atoms are broken and reformed. For example, in the reaction between sodium and chlorine, the two substances form a compound - sodium chloride, by transferring electrons from sodium to chlorine.

• Reactants: Substances that undergo change.
• Products: New substances formed as a result of the reaction.
• Synthesis Reaction: Two or more reactants combine to form one product.

Chemical reactions are represented by chemical equations, like \ \( 2\text{Fe} + 3\text{Cl}_2 \rightarrow 2\text{FeCl}_3 \ \), indicating the reactants and products with the correct stoichiometric coefficients.

Elemental Chlorine Reactivity

Chlorine is a non-metal element found in the halogen group of the periodic table known for its high reactivity.
Chlorine's reactivity stems from its electron configuration, having seven electrons in its outer shell, one short of the stable octet. This characteristic drives chlorine to actively seek electrons from other elements, particularly metals, to achieve a complete outer electron shell.
In reactions with metals, such as with iron to form iron(III) chloride, chlorine acts as an oxidizing agent by gaining electrons from the metal atoms. This makes chlorine a key participant in redox reactions.

• Powerful oxidizing agent: Chlorine gains electrons during reactions.
• Forms ionic compounds: Reacts with metals to produce metal chlorides.
• Reactivity ensures wide industrial use, such as in disinfection and bleaching.

The reactivity of chlorine is crucial for its role in forming compounds with metals, showcasing the unique behavior of halogens like chlorine in chemical processes.