To determine the correct stoichiometric ratio of particles (atoms, molecules, or formula units) of the substances in the chemical equation [tex]\(2 \, \text{Ag} (s) + \text{I}_2 (s) \rightarrow 2 \, \text{AgI} (s)\)[/tex], we need to pay close attention to the coefficients in front of each chemical species in the balanced equation.
### Step-by-Step Solution:
1. Identify the Reactants and Products:
- Reactants: [tex]\(2 \, \text{Ag} (s)\)[/tex] and [tex]\( \text{I}_2 (s)\)[/tex]
- Products: [tex]\(2 \, \text{AgI} (s)\)[/tex]
2. Determine the Coefficients:
- The coefficient of [tex]\(\text{Ag} (silver)\)[/tex] is 2.
- The coefficient of [tex]\(\text{I}_2 (iodine)\)[/tex] is 1.
- The coefficient of [tex]\(\text{AgI} (silver iodide)\)[/tex] is 2.
3. Write the Stoichiometric Ratios:
- The chemical equation shows that 2 atoms of Ag react with 1 molecule of [tex]\(\text{I}_2\)[/tex] to produce 2 formula units of [tex]\(\text{AgI}\)[/tex].
4. Convert to Moles (if necessary):
- In terms of moles, this ratio translates directly as:
[tex]\[
2 \, \text{moles Ag} : 1 \, \text{mole} \, \text{I}_2 : 2 \, \text{moles AgI}
\][/tex]
5. Verify the Options:
- Option 1: 1 atom Ag : 1 molecule [tex]\(I_2\)[/tex] : 2 molecules [tex]\(Ag\)[/tex] — This is incorrect because it states "1 atom of Ag" instead of "2 atoms of Ag".
- Option 2: 2 atoms Ag : 1 molecule [tex]\(I_2\)[/tex] : 2 formula units Ag — This is a close but subtly incorrect statement; it should be "2 formula units of [tex]\(AgI\)[/tex]" instead of "2 formula units Ag".
- Option 3: 2 molecules Ag : 1 molecule [tex]\(I_2\)[/tex] : 2 molecules Ag — This is incorrect because [tex]\(Ag\)[/tex] is in atomic form, not molecular.
- Option 4: 2 moles Ag : 1 mole [tex]\(I_2\)[/tex] : 2 moles AgI — This correctly represents the stoichiometric ratio of the reaction in terms of moles.
### Conclusion:
The correct ratio of particles of the substances in the chemical equation is 2 moles Ag : 1 mole I₂ : 2 moles AgI.
Thus, Option 4 is the correct answer.
