To calculate the mass of a given compound, one needs to look at the information given first. What we are given from the question is the molecular structure of paracetamol and the number of moles. The calculation is fairly simple now, all that we need is a periodic table, a calculator and the formula n = m/M.
We know that M is for molar mass, and n is number of moles, while m is the mass of a compound in grams. The atomic mass of paracetamol is calculated as follows:
C8 = 8 x 12.011 = 96.088
H9 = 9 x 1.008 = 9.072
N = 14.007
O2 = 2 x 15.999 = 31.998
Add them all up and your M for paracetamol is 151.165. Now your n is given as 0.0753, therefore:
0.0753 = m/151.165
m = 11.4 g
