Write and balance the equation for the decomposition of aluminum chloride into its elements. phase symbols are optional.
The Correct Answer and Explanation is:
The decomposition of aluminum chloride (AlCl₃) into its elements is a chemical reaction where aluminum chloride breaks down into its constituent elements: aluminum (Al) and chlorine (Cl₂).
Unbalanced equation:
AlCl3→Al+Cl2\text{AlCl}_3 \rightarrow \text{Al} + \text{Cl}_2AlCl3→Al+Cl2
Now, let’s balance this equation.
- Balancing aluminum (Al):
On the left side, we have one aluminum atom in AlCl₃, and on the right side, aluminum appears as a free element (Al). So, the number of aluminum atoms is already balanced. - Balancing chlorine (Cl):
On the left side, we have three chlorine atoms in AlCl₃. However, chlorine (Cl) on the right side appears as Cl₂, meaning two chlorine atoms per molecule of chlorine gas. Therefore, we need to balance chlorine by placing a coefficient of 3/2 in front of Cl₂ to match the three chlorine atoms on the left side. AlCl3→Al+32Cl2\text{AlCl}_3 \rightarrow \text{Al} + \frac{3}{2} \text{Cl}_2AlCl3→Al+23Cl2 - Removing the fraction:
To avoid fractions, we multiply the entire equation by 2. This gives us: 2AlCl3→2Al+3Cl22 \text{AlCl}_3 \rightarrow 2 \text{Al} + 3 \text{Cl}_22AlCl3→2Al+3Cl2
Final balanced equation:
2AlCl3→2Al+3Cl22 \text{AlCl}_3 \rightarrow 2 \text{Al} + 3 \text{Cl}_22AlCl3→2Al+3Cl2
Explanation:
- The reaction is a decomposition reaction, where a compound breaks down into simpler substances.
- Aluminum chloride (AlCl₃) is composed of aluminum and chlorine. When it decomposes, it produces aluminum (Al) and chlorine gas (Cl₂).
- The aluminum atoms on the left (in AlCl₃) are balanced by the aluminum atoms on the right side of the equation.
- Chlorine is more complex because it naturally forms a diatomic molecule (Cl₂). Hence, the number of chlorine atoms on both sides must be balanced by adjusting the coefficient of chlorine gas.
- The final balanced equation shows that for every 2 molecules of AlCl₃, you get 2 atoms of aluminum and 3 molecules of chlorine gas.
This decomposition reaction typically requires energy, such as heat or electrolysis, to break the ionic bonds in AlCl₃.
