To determine the correct formula equation for the reaction where fluorine gas ([tex]\(F_2\)[/tex]) is placed in contact with calcium metal ([tex]\(Ca\)[/tex]) at high temperatures, we need to analyze the reactants and products in each of the given options, and then verify which one makes chemical sense.
1. Reactants:
- Fluorine gas ([tex]\(F_2\)[/tex]): a diatomic molecule, gaseous at room temperature.
- Calcium metal ([tex]\(Ca\)[/tex]): a solid metal.
2. Product:
- Calcium fluoride ([tex]\(CaF_2\)[/tex]): an ionic compound formed from calcium and fluorine.
From the options:
1. [tex]\(F_2(l) + Na(s) \longrightarrow NaF_2(s)\)[/tex]
- This equation is incorrect because it involves sodium ([tex]\(Na\)[/tex]) instead of calcium.
2. [tex]\(F_2(g) + Ca(s) \longrightarrow CaF_2(l)\)[/tex]
- This equation correctly involves fluorine gas and calcium metal. However, the state of [tex]\(CaF_2\)[/tex] should be solid (s) in typical conditions, not liquid (l).
3. [tex]\(F_2(g) + Na(s) \xrightarrow{\Delta} NaF_2(l)\)[/tex]
- Again, this equation involves sodium instead of calcium.
4. [tex]\(F_2(g) + Ca(s) \xrightarrow{\triangle} CaF_2(s)\)[/tex]
- This equation correctly shows the reaction of fluorine gas with calcium metal to produce calcium fluoride, and indicates that calcium fluoride is solid (s) at room temperature. The triangle (Δ) represents added heat, indicating the reaction occurs at high temperatures.
Therefore, the correct formula equation for the reaction is:
[tex]\[ F_2(g) + Ca(s) \xrightarrow{\triangle} CaF_2(s) \][/tex]
