[Nathaniel]

A reaction has a rate r = k[ B]^2. When 2.73 mol of B are present in 4.50 L container and the reaction begins, the initial rate is 8.62 mol/(L s). What is the value for k (in L/(mol s)?


Heres how I answered it

k = 8.62/ L s (4.50 L/ 7.4529)

=5.17 L/(mol s)?

but the correct answer is 23. 4L/(mol s)?

[Yggdrasil]

[ B] should be squared.

[Marcus Soutlo]

I did [ B]² already to get 7.4529 (look above)

[Yggdrasil]

[B ] = moles of B/volume = 2.73mol/4.50L

You need to square both the numerator and the denominator.

[Marcus Soutlo]

[B ] = moles of B/volume = 2.73mol/4.50L

      = 2.73^2 / 4.50^2

      =7.4529 / 20.25

      = 0.3679

What is my next step?

Thanks again

[Padfoot]

solve for k.