How many formula units of baking soda (sodium bicarbonate) are in 2.30 tsp? (1 tsp ≈ 7.50 g NaHCO3)?

Molar mass of NaHCO₃ = (23.0 + 1.0 + 12.0 + 16.0×3) g/mol = 84.0 g/mol
Mass of NaHCO₃ = (7.50 g) × 2.30 = 17.3 g
No. of moles of NaHCO₃ = (17.3 g) / (84.0 g/mol) = 0.206 mol

1 mole of NaHCO₃ contains 6.022 × 10²³ formula units.
No. of formula units of NaHCO₃ = (0.206 mol) × (6.022 × 10²³ formula units/mol) = 1.24 × 10²³ formula units

there are 9.500 units