# What is the number of grams in 0.600 mole of Cl_2?

$\text{Mass} = 2 \times 35.45 \cdot g \cdot \cancel{m o {l}^{-} 1} \times 0.600 \cdot \cancel{m o l} \cong 42 \cdot g$
The molecular mass of chlorine gas is $2 \times 35.45 \cdot g \cdot m o {l}^{-} 1$. Why is it $2 \times$? What is the mass of an equivalent molar quantity of fluorine gas?