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A sample of sodium reacts completely with 0.426 kg of chlorine, forming 702 g of sodium chloride. What mass of sodium reacted? Express your answer to three significant figures and include the appropriate units.

Respuesta :

The given reaction is:

[tex]2Na (s)+ Cl_{2}(g)\rightarrow 2NaCl(s)[/tex]

First, calculate the number of moles of sodium chloride.

Number of moles  =[tex]\frac{given mass in g}{molar mass}[/tex]

Molar mass of sodium chloride  =[tex]58.44 g/mol[/tex]

Number of moles of [tex]NaCl[/tex] = [tex]\frac{ 702 g}{58.44 g/mol}[/tex]

= [tex]12 moles[/tex]

Now, from the reaction; two moles of sodium gives two moles of sodium chloride.

So, 12 moles of sodium chloride needed = [tex]\frac{2}{2}\times 12[/tex] moles of sodium.

Thus, number of moles of sodium = [tex]12[/tex] moles

Now, mass of sodium  =[tex]number of moles \times molar mass[/tex]

= [tex]12 moles \times 23 g/mol[/tex]

=[tex]276 g[/tex]

Thus, mass of sodium  = [tex]276 g[/tex]

mariejoepagaduan

276 grams of sodium reacted with 0.426 kg of chlorine to form 702 g of sodium chloride.

Further Explanation

This is an example of a simple stoichiometry problem.

To determine the mass of sodium that reacted, two paths may be used:

  1. use the stoichiometric ratio between sodium and chlorine
  2. use the stoichiometric ratio between sodium and sodium chloride

To solve this problem, first write the balanced chemical equation:

2Na + Cl₂ → 2 NaCl

Based on the stoichiometric ratio, we can determine the mass of sodium that reacted through dimensional analysis.

1) Using the stoichiometric ratio of sodium and chlorine

[tex]mass \ Na \ = 0.426 \ kg \ Cl_2 \times \frac{1000 \ g}{1 \ kg} \times \frac{1 \ mol \ Cl_2}{70.906 \ g} \times \frac{2 \ mol \ Na}{1 \ mol \ Cl_2} \times \ \frac{22.989 \ g \ Na}{1 \ mol \ Na}\\\\\boxed {mass \ Na = 276.23 \ g}[/tex]

2) Using the stoichiometric ratio of sodium and sodium chloride

[tex]mass \ Na = 702 \ g \ NaCl \times \frac{1 \ mol \ NaCl}{58.442 \ g} \times \frac{2\ mol \ Na}{2 \ mol \ NaCl} \times \frac{22.989 \ g \ Na}{1 \ mol \ Na}\\\\\boxed {mass \ Na = 276.14 \ g}\\[/tex]

Since the mass of Na is required to be given in three significant figures, then the final answer is:

[tex]\boxed {\boxed {mass \ Na = 276 \ g}}[/tex]

Learn More

  • Dimensional Analysis https://brainly.com/question/2749176
  • Neutralization https://brainly.com/question/7201942

Keywords: stoichiometry, moles

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