please help!

The gas phase reaction between hydrogen and iodine is proposed to occur as follows: step1fast:I2II2Istep2slow:H2+2I2HI (1) What is the equation for the overall reaction? Use the smallest integer coefficients possible. If a box is not needed, leave it blank. (2) Which species acts as a catalyst? Enter formula. If none, leave box blank: (3) Which species acts as a reaction intermediate? Enter formula. If none, leave box blank: (4) Complete the rate law for the overall reaction that is consistent with this mechanism. Use the form k[A]m[B]n, where " 1 " is understood (so don't write it if it's a "1") for m,n, etc