You normally take 2 Ibuprofen (C13H18O2) when you have pain. Each one is 250 g. How many moles of ibuprofen do you take?

2.4mol

Explanation:

In order to calculate numbers of moles we have to divide the given mass by the molar mass of the substance (ibuprofen) n = m/M

To calculate the molar mass we have

C13 = 12*13 = 156

H18 = 1*18=18

O2 = 16*2 = 32

Molar mass M = 153+18+32 = 206g

Given the mass m = 250g per tablet

Hence number of moles in one tablet is n = 250/206 = 1.2 mol

Therefore the total number of ibuprofen you took is 1.2*2 (for the two tablets) = 2.4 moles