A batch reactor is used to produce a certain chemical. The reaction rate is first order with respect to the concentration of the reactant, and the reaction rate constant is 0.15 1/min. The reactant is fed into the reactor at a concentration of 0.5 mol/L and the initial volume of the reactor is 10 L. The reactor operates isothermally, and the final volume is 15 L. Calculate the conversion of the reactant in the reactor.