[qw098]

Hi guys,

I have a midterm tomorrow and I am stuck on this question:

1. I2(g)   -k1->   2 I(g)
2. 2 I(g)   -k2->   I2(g)
3. H2(g) + 2 I(g)   -k3->   2 HI(g)

It says:

rate of producing I = 2 k1 [I2]
rate of consuming I = 2 k2 2 + 2 k3 [H2] 2.

Why is the coefficient "2" present? I am so confused!

Thanks,
And any help would greatly be appreciated!

[Schrödinger]

Consider equation 1
Rate of producing 2 moles of I = k1 [I2].
So, the rate at which one mole is being produced is twice this.

 
   {dI/dt}/2 = -dI/dt = Rate of reaction
=> {dI/dt}/2 = k1[I2] = rate of reaction

Please clarify if you have any doubts regarding my explanation. I had to hurry with the explaining part, since I don't have much time