Answer:
1.138 × 10²³ molecules of oxalic acid
Explanation:
Avogadro's number is equal to 6.022 × 10²³ and it tells you the number of molecules in 1 mole of substance.
So now we devise the following reasoning:
if 1 mole of oxalic acid contains 6.022 × 10²³ molecules
then 0.189 moles of of oxalic acid contains X molecules
X = (0.189 × 6.022 × 10²³) / 1 = 1.138 × 10²³ molecules of oxalic acid
