Question

The reaction below shows the decomposition of sodium azide into sodium metal and nitrogen gas.

2NaN3(s)-> 2Na(s) + 3N2(s)
An unknown amount of sodium azide (NaN3) reacts and produces 744 mL of nitrogen gas. What mass of sodium metal is produced?

Answer 1

0.51g

Step-by-step explanation:

Given parameters:

Volume of nitrogen gas = 744mL

Unknown:

Mass of sodium metal produced = ?

Solution:

Let us assume that the gas, nitrogen was collected at STP which is the standard temperature and pressure, we can easily find its number of moles.

Number of moles =
`(volume of gas)/(22.4)`

since the gas volume given is 744mL = 0.744mL

Therefore input the variables;

Number of moles =
`(0.744)/(22.4)` = 0.03moles

Now that we know the number of moles of the gas, let us revisit the reaction equation:

2NaN₃ → 2Na + 3N₂

It good to ensure that the reaction is balanced;

3 mole of nitrogen gas is produced with 2 moles of Na

0.03 mole of nitrogen gas will be produce with
`(0.03 x 2)/(3)` = 0.02mole

So;

Using;

mass = number of moles x molar mass

let us solve for the mass of Na;

molar mass of Na = 23g/mol

mass = 0.02 x 23 = 0.51g