A fertilizer is advertised as containing 17.3% sodium nitrate, NaNO3 (by mass). How much NaNO3 molecules is there in 0.520 kg of fertilizer?

6.37 × 10²³ molecules

Explanation:

The molar mass of NaNO₃ = (23 × 1) + (14 ×1) + (16 × 3) = 23 + 14 + 48 = 85 g/mol

Since the fertilizer contains 17.3% sodium nitrate, The number of sodium nitrate in 0.520 kg of fertilizer = 17.3% × 0.520 kg = 0.173 × 520 g = 89.96 g

Number of moles of NaNO₃ in 0.520 kg of fertilizer =  89.96 g / 85 g/mol = 1.0584 moles

Number of molecules of NaNO₃ in 0.520 kg of fertilizer =  1.0584 moles × 6.02 × 10²³ = 6.37 × 10²³ molecules