3.31 × 10^23 molecules
We are given;
The number of moles = 0.55 moles
We are required to calculate the number of molecules in 0.55 moles of sodium nitrate.
We know that 1 mole of a compound contains molecules equivalent to the Avogadro's number, 6.022 × 10^23.
Therefore;
1 mole of NaNO₃ = 6.022 × 10^23 molecules
Thus, for 0.55 moles will contain;
= 0.55 moles × 6.022 × 10^23 molecules
= 3.31 × 10^23 molecules
Hence, 0.55 moles will contain 3.31 × 10^23 molecules