A 0.105-g sample of an unknown metal (x) reacted w/ hydrochloric acid according to the equation...?

X(s) + HCl(aq) → XCl3(aq) + H2(g) ---- The volume of hydrogen gas collected over water was 144mL at 22°C and a barometer reading of 764 mm Hg. Calculate the atomic m of the unknown metal.