How does 1 mole of a compound = the molecular weight of the compound?

Question

I am reviewing moles, and came across this sentence in my book:

One mole of a compound has a mass in grams equal the molecular weight of the compound expressed in amu and contains $6.022\times10^{23}$ molecules of that compound.

Now, I perfectly understand the second part of the sentence. 1 mole of compound has $6.022\times10^{23}$ molecules. But how do $6.022\times10^{23}$ molecules have a mass same as the molecular weight of compound?
Ex. Molecular weight of $\ce{SOCl2}$ is $119\ \mathrm{amu}$. That is the mass of 4 atoms. How do $6.022\times10^{23}$ molecules have the same mass?

Answer 1

Well you can actually calculate it like this $$1\ \mathrm{amu}=1.66\times10^{-27}\ \mathrm{kg}$$ Therefore $$119\ \mathrm{amu}=119\times1.66\times10^{-27}\ \mathrm{kg}$$ But for 1 mole, multiplying by Avogadro number you get mass of one mole as $$\begin{align} 119\times1.66\times10^{-27}\times6.022\times10^{23}&=0.11899\ \mathrm{kg}\\ &=118.99\ \mathrm g\\ &\approx119\ \mathrm g \end{align}$$