Question

What mass in grams of sodium nitrate, NANO3, is produced if 20.0g of sodium azide, NaN3, in a dilute aqueous solution are reacted with excess silver nitrate, AgNO3, according to the following chemical equation?

NaN3(aq) + AgNO3(aq) --> AgN3(s) + NaNO3(aq)

Answer 1

1) Write the balanced equation

 
NaN3(aq) + AgNO3(aq) --> AgN3(s) + NaNO3(aq)


2) State the relevant theoretical ratio for the products and reactants in which you have the focus.

1mol NaN3 / 1mol NaNO3 or  mol NaNO3 / 1mol NaN3 

3) Transform the mass data into moles using the molar masses.

- molar mass of NaN3 = 23 g/mol + 3*14g/mol = 65 g/mol

- # of moles, n = mass / molar-mass = 20.0g / 65.0 g/mol = 0.3077 mol

4) From the theoretical ratio, get the number of moles produced. In this case the ratio is 1:1, so the number of moles of NaNO3 is also 0.3077 mol

5) Convert to mass, by multiplying by the molar mass of NaNO3

- molar mass of NaNO3: 23g/mol + 14g/mol + 3*16g/mol =  85 g/mol

- mass of NaNO3 = 0.3077 mol * 85g/mol =  26.15 g

Answer: 26.15 g