When the following equation is balanced, the stoichiometric coefficient of H2S is ________.FeCl3(aq) + H2S(g) → Fe2S3(s) + HCl(aq)

To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation.

1. Start with the equation: FeCl3(aq) + H2S(g) → Fe2S3(s) + HCl(aq)

2. Balance the Fe atoms first. There are 2 Fe atoms on the right side, so we need 2 Fe atoms on the left side. This gives us: 2FeCl3(aq) + H2S(g) → Fe2S3(s) + HCl(aq)

3. Next, balance the S atoms. There are 3 S atoms on the right side, so we need 3 S atoms on the left side. This gives us: 2FeCl3(aq) + 3H2S(g) → Fe2S3(s) + HCl(aq)

4. Finally, balance the Cl and H atoms. There are 6 Cl atoms on the left side, so we need 6 Cl atoms on the right side. There are 6 H atoms on the left side, so we need 6 H atoms on the right side. This gives us: 2FeCl3(aq) + 3H2S(g) → Fe2S3(s) + 6HCl(aq)

So, the stoichiometric coefficient of H2S is 3.