Question

Suppose a thin sheet of zinc containing 0.2 mol of the metal is completely converted in air to zinc oxide (zno) in one month. how would you express the rate of conversion of the zinc?

Answer 1

molecular mass of  Zn = 65.38  
1 mol = 65 g 
0.2 mol of Zinc = 13.076 g of Zinc 

13.076 g of Zinc is completely converted in air to ZnO in one month
= 13.076 g / 30 days = 0.435 g per day 

The rate of conversion of the zinc = 0.44 g / day

Answer 2

Answer:

$r_{Zn}=-kC_{Zn}^2C_{O_2}$

Explanation:

Hello,

In this case, the mentioned reaction should be:

$2Zn(s)+O_2(g)\rightarrow 2ZnO$

In such a way, considering an irreversible reaction and an elemental reaction, the power of each compound's concentration equals the stoichiometric coefficient in its reaction, thus:

$r_{Zn}=-kC_{Zn}^2C_{O_2}$

It turns out negative since it is a consumption upon zinc.

Best regards.