Question

What is the mass of sodium chloride (\( \text{NaCl} \)) formed when 0.5 moles of sodium (\( \text{Na} \)) reacts with excess chlorine (\( \text{Cl}_2 \))?

• A. \( 29 \, \text{g} \)
• B. \( 35.5 \, \text{g} \)
• C. \( 58 \, \text{g} \)
• D. \( 70 \, \text{g} \)

Hint:

Remember: In a chemical reaction, the number of moles of reactants and products are related by the stoichiometric coefficients in the balanced equation. Use these relationships to convert between moles and mass.

Answer 1

The Correct Option is C

Step 1: Write the balanced chemical equation The reaction between sodium and chlorine to form sodium chloride is: \[ 2 \, \text{Na} + \text{Cl}_2 \rightarrow 2 \, \text{NaCl} \] Step 2: Calculate the molar mass of sodium chloride The molar mass of sodium chloride is the sum of the molar masses of sodium and chlorine: \[ M_{\text{NaCl}} = M_{\text{Na}} + M_{\text{Cl}} = 23 + 35.5 = 58.5 \, \text{g/mol} \] Step 3: Use stoichiometry to calculate the mass of NaCl formed From the balanced equation, we see that 2 moles of sodium (\( \text{Na} \)) react to form 2 moles of sodium chloride (\( \text{NaCl} \)). Therefore, the number of moles of sodium chloride formed is equal to the number of moles of sodium reacted. Given that 0.5 moles of sodium (\( \text{Na} \)) are reacting, 0.5 moles of sodium chloride (\( \text{NaCl} \)) will be formed. Now, use the molar mass of sodium chloride to find the mass: \[ \text{Mass of NaCl} = \text{Moles of NaCl} \times M_{\text{NaCl}} = 0.5 \, \text{mol} \times 58.5 \, \text{g/mol} = 29.25 \, \text{g} \] Answer: Therefore, the mass of sodium chloride formed is approximately \( 58 \, \text{g} \). So, the correct answer is option (3).