Which of the following can indicate a chemical change?
A. bubbles
B. melting
C, freezing
D. paper

Be sure to answer all parts. the catalytic destruction of ozone occurs via a two-step mechanism, where x can be any of several species: (1) x + o3 → xo + o2 [slow] (2) xo + o → x + o2 [fast] (a) write the overall reaction. o3 + o → 2 o2 o3 + xo → x + 2 o2 xo + x + o3 + o → xo + x + 2 o2 x + o3 → xo + o2 (b) write the rate law for each step (using k for the rate constant). reaction 1: reaction 2: k[x][o2] k[xo][o2] k[x][o3] k[xo][o3] k[xo][o2] k[x][o] k[x][o2] k[xo][o] (c) x acts as a and xo acts as a catalyst intermediate intermediate catalyst (d) high-flying aircraft release no into the stratosphere, which catalyzes this process. when o3 and no concentrations are 3 ă— 1012 molecule/cm3 and 9.9 ă— 109 molecule/cm3, respectively, what is the rate of o3 depletion? the rate constant k for the rate-determining step is 6 ă— 10â’15 (cm3)2/moleculeâ·s. give your answer in scientific notation. use one significant figure in your answer. ă— 10 molecule/s