Wednesday
May 22, 2013

Posted by Amelia on Sunday, November 29, 2009 at 6:44am.

Can you give me some help with this question im not sure how to even start

in a reaction A to P
the mass of A at any given time T is Mt and the rate of transformation of A at time T is prportional to Mt given that the original mass of A is 130g and that 50g has been transformed after 120 seconds

form and solve a differential equation relating Mt to t
and find the mass of A transformed over a 300sec period

d(M(t))/dt = -kM(t)
where k is a constant.
Rearranging and integrate
d(M(t))/M(t) = -kdt
ln(M(t))= -kt + C
where C is an arbitrary constant
M(t) = e-kt+C ....(1)
Put eC=ln(Mo), the initial mass of A.
(1) can be rewritten as
M(t)=Mo e-kt
At t=0, e-kt=1, Mo=130.
At t=120, M(120)=130-50=80
Therefore
M(120)=80=130e-k(120)
from which k=0.004 approx.
Thus
M(t)=Mo e-0.004t

The amount transformed at t=300 can be calculated from the expression
M(0)-M(300).

Related Questions

Maths - Can you give me some help with this question im not sure how to even ...
Chemistry 2 Ap - Can someone please help me ? What mass of glycerol must be ...
enviromental studies - please could someone help me with my enviro homework im ...
Physics - I've been stuck on this problem for a while. Im not sure where to ...
Maths - i have an answer but im not sure if its right would you tell me please ...
maths - trigonometry - I have my maths exam on Tuesday and cannot remember how ...
english check - A)all of the copies has been made b)none of the stores are on my...
bobpursley - ok thiis is my work for the next question. im i right? im not sure ...
scientist - hi i am doing a science fair project.The project is testing memory. ...