Questions: Balance the entire chemical reaction using an atom inventory. Remember to balance each element in the reaction. Al + Cl2 -> AlCl3 When the equation is balanced, what is the coefficient for chlorine, Cl2?

Balance the chemical reaction using an atom inventory.

Identify the number of atoms of each element on both sides of the equation.

On the left side of the equation:

• Aluminum (\(\mathrm{Al}\)): 1 atom
• Chlorine (\(\mathrm{Cl}\)): 2 atoms (from \(\mathrm{Cl}_2\))

On the right side of the equation:

• Aluminum (\(\mathrm{Al}\)): 1 atom (from \(\mathrm{AlCl}_3\))
• Chlorine (\(\mathrm{Cl}\)): 3 atoms (from \(\mathrm{AlCl}_3\))

Balance the aluminum atoms.

The number of aluminum atoms is already balanced with 1 atom on both sides.

Balance the chlorine atoms.

To balance the chlorine atoms, we need to have the same number of chlorine atoms on both sides. Since \(\mathrm{Cl}_2\) has 2 chlorine atoms and \(\mathrm{AlCl}_3\) has 3 chlorine atoms, we need to find a common multiple of 2 and 3, which is 6.

Thus, we need 3 \(\mathrm{Cl}_2\) molecules to get 6 chlorine atoms on the left side and 2 \(\mathrm{AlCl}_3\) molecules to get 6 chlorine atoms on the right side.

The updated equation is: \[ \mathrm{Al} + 3\mathrm{Cl}_2 \rightarrow 2\mathrm{AlCl}_3 \]

Balance the aluminum atoms again.

Now, we have 2 aluminum atoms on the right side (from 2 \(\mathrm{AlCl}_3\)), so we need 2 aluminum atoms on the left side.

The final balanced equation is: \[ 2\mathrm{Al} + 3\mathrm{Cl}_2 \rightarrow 2\mathrm{AlCl}_3 \]

The coefficient for chlorine, \(\mathrm{Cl}_2\), is \(\boxed{3}\).

The coefficient for chlorine, \(\mathrm{Cl}_2\), is \(\boxed{3}\).