GC and HPLC are instrumental chromatographic techniques - Leaving Cert Chemistry - Question h - 2019

To find the number of milligrams in a single dose, we need to compute the amount of ibuprofen in grams and then convert that to milligrams.

1. Calculate the molar mass of ibuprofen (C13H18O2):

   $M_m = 206 ext{ g/mol}$

2. Use the formula to find the number of moles:

   $n = \frac{m}{M_m}$

   Rearranging gives:

   $m = n imes M_m$

3. Substitute the values (with moles given as 4.86 × 10⁻⁶):

   $m = 4.86 \times 10^{-6} ext{ mol} \times 206 ext{ g/mol} = 0.000100116 ext{ g}$

4. Convert grams to milligrams:

   $0.000100116 ext{ g} = 100.116 ext{ mg}$

Therefore, the dosage contains approximately 100 mg of ibuprofen.