1. Write the balanced chemical equation:

2 Na + Cl₂ → 2 NaCl

2. Determine the molar masses of the relevant substances:

* Sodium (Na): 22.99 g/mol

* Chlorine (Cl₂): 35.45 g/mol * 2 = 70.90 g/mol

* Sodium chloride (NaCl): 22.99 g/mol + 35.45 g/mol = 58.44 g/mol

3. Calculate the moles of sodium chloride:

* Moles of NaCl = mass of NaCl / molar mass of NaCl

* Moles of NaCl = 117 g / 58.44 g/mol = 2.00 mol

4. Use the mole ratio from the balanced equation to find moles of chlorine:

* From the equation, 1 mole of Cl₂ reacts to produce 2 moles of NaCl.

* Therefore, 2.00 mol NaCl requires 2.00 mol NaCl * (1 mol Cl₂ / 2 mol NaCl) = 1.00 mol Cl₂

5. Calculate the mass of chlorine:

* Mass of Cl₂ = moles of Cl₂ * molar mass of Cl₂

* Mass of Cl₂ = 1.00 mol * 70.90 g/mol = 70.9 g

Answer: You need 70.9 grams of chlorine gas to make 117 grams of sodium chloride.