HELP!!

Thi useful metal manganese can be extracted from the mineral rhodochrosite by a two-step process. In the first step. manganese(II) earhonate and oxygen react to form manganese(IV) oxide and carbon dioxide: 2MnCO3(s)+O2(g)2MnO2(s)+2CO2(g) In the second step, manganese(tV) oxide and aluminum react to focm manganese and aluminum oxdide: 3MnO2(s)+4Al(s)3Mn(s)+2Al2O3(s) Suppose the yieid of the first step is 85% and the yieid of the second step is 80,%. Calculate the mass of manganese;ti) carbenate required to make 1.0 ki of manganese. Be sure your answer has a unit symbol, if needed, and is rounded to the correct number of significant digits