Solving First-Order Kinetics for [B] After 7.00 Minutes

[geffman1]

We examine the reaction A B which displays first-order kinetics. We know that k = 0.30 / min.
If we begin with [A] = 0.54 M what will be after exactly 7.00 minutes?


hey i used the formula In[A]/[Ao]=-kt then rearranged to In[A]=-kt+[InAo]
when i sub it in i get In[A]=-0.3x7+In[0.54] and i get the answer 0.066 however the answer is 0.47M. i tired converting to second and still didnt work. any help would be good. thanks

 

[cepheid]

There's nothing wrong with your math.* The amount of [A] left is 0.066. The question is not asking you for the amount of [A] left. It is asking you for the amount of produced.

*Well, other than the fact that it is supposed to be Ln, not In. Natural Logarithm.

 

[geffman1]

ta, how do i work out how much is produced?

 

[geffman1]

dw, I am stupit. thanks mate

 

[cepheid]

A is being converted to B in this chemical reaction, right? If 0.066 is left, what happened to the rest of it? It became B.