Balance the chemical equation. Based on the equation, how many grams of chlorine are produced when sodium chloride decomposes and produces 19.5 grams of sodium? Use the periodic table to find the atomic weights of the elements.



Answer :

Sure, let's walk through the solution step by step.

1. Balanced Chemical Equation:

The chemical reaction for the decomposition of sodium chloride (NaCl) can be written as:
[tex]\[ 2 \text{NaCl} \rightarrow 2 \text{Na} + \text{Cl}_2 \][/tex]
This equation is balanced as there are 2 sodium (Na) atoms and 2 chlorine (Cl) atoms on both sides of the equation.

2. Given Information:

- Mass of sodium produced: 19.5 grams.

3. Molar Masses:

- Molar mass of Sodium (Na): 22.99 g/mol.
- Molar mass of Chlorine (Cl): 35.45 g/mol.
- Molar mass of Sodium Chloride (NaCl): 22.99 + 35.45 = 58.44 g/mol.

4. Calculate Moles of Sodium (Na) Produced:

We use the molar mass to convert the given mass of sodium to moles:
[tex]\[ \text{Moles of Na produced} = \frac{\text{mass of Na}}{\text{molar mass of Na}} = \frac{19.5 \text{ g}}{22.99 \text{ g/mol}} \approx 0.848 \text{ moles} \][/tex]

5. Stoichiometric Relationships:

According to the balanced chemical equation, 2 moles of NaCl produce 2 moles of Na and 1 mole of [tex]\( \text{Cl}_2 \)[/tex].

Therefore, the moles of [tex]\( \text{Cl}_2 \)[/tex] produced will be:
[tex]\[ \text{Moles of } \text{Cl}_2 \text{ produced} = \frac{\text{Moles of Na produced}}{2} = \frac{0.848 \text{ moles}}{2} \approx 0.424 \text{ moles} \][/tex]

6. Calculate the Mass of Chlorine Gas ([tex]\( \text{Cl}_2 \)[/tex]) Produced:

The molar mass of [tex]\( \text{Cl}_2 \)[/tex] is twice the molar mass of a single chlorine atom:
[tex]\[ \text{Molar mass of } \text{Cl}_2 = 2 \times 35.45 \text{ g/mol} = 70.90 \text{ g/mol} \][/tex]

Hence, the mass of [tex]\( \text{Cl}_2 \)[/tex] produced can be calculated as:
[tex]\[ \text{Mass of } \text{Cl}_2 \text{ produced} = \text{moles of } \text{Cl}_2 \text{ produced} \times \text{molar mass of } \text{Cl}_2 = 0.424 \text{ moles} \times 70.90 \text{ g/mol} \approx 30.07 \text{ grams} \][/tex]

Thus, approximately 30.07 grams of chlorine gas ([tex]\( \text{Cl}_2 \)[/tex]) are produced when sodium chloride decomposes to produce 19.5 grams of sodium.