Question

In the following reaction, 2NaN₃ decomposes to form 2Na plus 3N2. If 500 g of NaN3 decomposes to form 323.20 g of N2, how much Na is produced?

Answer 1

The reaction produces 176.85 g of Na.

The balanced equation is

2NaN₃ → 2Na + 3N₂

You can use either the mass of NaN₃ or of N₂ to calculate the mass of Na.

Using Mass of NaN₃

You must make the following conversions:

mass of NaN₃ → moles of NaN₃ → moles of Na → mass of Na

500 g NaN₃ × `(1" mol NaN₃")/(65.01" g NaN₃")` = 7.69 mol NaN₃

7.69 mol NaN₃ × `(2 " mol Na")/(2 " mol NaN₃")` = 7.69 mol Na

7.69 mol Na × `(22.99 " g Na")/(1" mol Na")` = 176.8 g Na

Using Mass of N₂

You must make the following conversions:

mass of N₂ → moles of N₂ → moles of Na → mass of Na

323.20 g Na × `(2" mol N₂")/(28.01" g N₂")` = 11.539 mol N₂

11.539 mol N₂ × `(2 " mol Na")/(3 " mol N₂")` = 7.692 mol Na

7.692 mol Na × `(22.99 " g Na")/(1" mol Na")` = 176.85 g Na