1 mol of boron has a mass of #10.81##g#. To find the molar quantity divide the mass by the molar mass.
Explanation:
Molar quantity #=##(3.70xx10^(-1)*cancelg)/(10.81*cancelg*mol^-1)##=##?? mol#. Note how this treatment is dimensionally consistent; I used #g# and #g*mol^-1# units, and I get an answer in #mol# as required #((mol^-1)^-1=mol)#.