## Chemistry 12th Edition

We know that $PV=nRT$ This can be rearranged as: $n=\frac{PV}{RT}$ We plug in the known values to obtain: $n=\frac{97970\times 0.0041}{8.31\times 285}=0.17651molH_2$ The given reaction is : $LiH+H_2O\rightarrow LiOH+H_2O$ moles ratio $LiH:H_2$=1:1 $moles \space of LiH=0.17651moles$ $Mass\space of \space LiH=moles\times molar\space mass$ $Mass\space of \space LiH=0.17651\times 7.9491=1.40g$