The number of molecules of sodium nitrate that reacted is
1.6 x10^23 molecules
calculation
NaN₃(aq) +AgNO₃(aq) → AgN₃(s) + NaNo₃ (aq)
step 1: find moles of NaN₃
moles = mass÷molar mass
from periodic table the molar mass of NaN₃ = 23 +( 3 x 14)= 65 g/mol
moles =17 g÷65 g/mol = 0.262 moles
Step 2: use the mole ratio to calculate the moles of NaNO₃
NaN₃:NaNO₃ is 1:1
Therefore the moles of NaNO₃ is also = 0.262 moles
Step 3: use the Avogadro's law constant to calculate the number of molecules of NaNO₃
That is according to Avogadro's law
1 mole = 6.02 x10^23 molecules
0.262 moles= ? molecules
by cross multiplication
=[(0.262 moles x 6.02 x10^23 molecules) / 1 mole] = 1.6 x10^23 molecules