$\text{100}\text{mL}$ of $\text{0}\text{.3}\text{M}$ acetic acid is shaken with $\text{0}\text{.8}\text{g}$ wood charcoal. The final concentration of acetic acid in the solution after adsorption is $\text{0}\text{.125}\text{M}$. The mass of acetic acid adsorbed per gram of charcoal is