Final answer:
To find the number of formula units in 3.5 grams of NaOH, calculate the number of moles from the mass and the molar mass of NaOH, then multiply by Avogadro's number to get approximately 5.27 x 10^22 formula units.
Step-by-step explanation:
To determine how many formula units are in 3.5 grams of NaOH, we need to calculate the number of moles of NaOH and then convert that to formula units using Avogadro's number.
Steps to Calculate Formula Units of NaOH
Calculate the molar mass of NaOH.
Convert the mass of NaOH in grams to moles using its molar mass.
Use Avogadro's number to convert moles to formula units.
Molar mass of NaOH = 22.990 g/mol for Na + 15.999 g/mol for O + 1.008 g/mol for H = 40.00 g/mol.
Next, we convert the mass of NaOH to moles: moles of NaOH = mass of NaOH / molar mass of NaOH = 3.5 g / 40.00 g/mol = 0.0875 moles.
Finally, we calculate the number of formula units: formula units of NaOH = moles of NaOH x Avogadro's number = 0.0875 moles x 6.022 x 1023 units/mol = 5.27 x 1022 formula units.