How Does the Reaction Between Chemicals A and B to Form C Progress Over Time?

Click For Summary
SUMMARY

The reaction between chemicals A and B to form chemical C is governed by a rate law that is jointly proportional to the amounts of A and B not yet converted to C. Initially, 50 grams of A and 80 grams of B are present, with a conversion ratio of 2 grams of A to 3 grams of B. After 10 minutes, 100 grams of C are produced, leading to the conclusion that, after a long period, 125 grams of C will be formed, leaving 0 grams of A and 5 grams of B remaining. The equilibrium favors the formation of C, as no back reaction is indicated in the kinetic laws.

PREREQUISITES
  • Understanding of chemical kinetics and reaction rates
  • Familiarity with differential equations and partial fraction decomposition
  • Knowledge of stoichiometry and reaction ratios
  • Basic grasp of equilibrium concepts in chemical reactions
NEXT STEPS
  • Study the principles of chemical kinetics and rate laws
  • Learn about solving differential equations in chemical contexts
  • Explore stoichiometric calculations for chemical reactions
  • Investigate equilibrium dynamics and the concept of reaction reversibility
USEFUL FOR

Chemistry students, chemical engineers, and professionals involved in reaction kinetics and process optimization will benefit from this discussion.

Dustinsfl
Messages
2,217
Reaction score
5
Two chemicals, A and B, are combined, forming chemical C. The rate of the reaction is jointly proportional to the amounts of A and B not yet converted to C. Initially, there are 50 grams of A and 80 grams of B, and, during the reaction, for each two grams of A used up in the conversion, there are three grams of B used up. An experiment shows that 100 grams of C are produced in the first 10 minutes. After a long period of time, how much of A and B remains, and how much of C has been reproduced?

dx/dt = k*(50-\frac{2}{5}*x)*(80-\frac{3}{5}*x)


After separation and solving for partial fractions, I obtain:

\int\frac{1}{10-2*x} - \frac{3}{2}\int\frac{1}{16-3*x} = k*t+c

Which then yields:

\frac{16-3*x}{10-2*x} = C*e^{2*k*t}

C=8/5

k=\frac{ln(71/76)}{20}

However, something is wrong with my final equation solved for x(t) due to x(0) doesn't = 0 and x(10) doesn't = 100.
 
Physics news on Phys.org
x is the amount of chemical C, right? I think you making more than one mistake. You've got a (50-2x/5) going in and a (10-2*x) coming out in the partial fractions. Those aren't proportional to each other. (50-2x/5)=(250-2x)/5=(125-x)*(2/5).
 
You might as well get that sorted out, but an odd or trick question it seems to me, with superfluous information. Are you sure it is about kinetics despite the kinetic info in it? :confused: The equlibibrium is all towards product since there is no mention of back reaction in the kinetic laws given. 50g of A reacting in a 2:3 ratio with B will after a long time give you 125g of C leaving 0 A and 5g of B it seems to me.
 
epenguin said:
You might as well get that sorted out, but an odd or trick question it seems to me, with superfluous information. Are you sure it is about kinetics despite the kinetic info in it? :confused: The equlibibrium is all towards product since there is no mention of back reaction in the kinetic laws given. 50g of A reacting in a 2:3 ratio with B will after a long time give you 125g of C leaving 0 A and 5g of B it seems to me.

Good point. I wasn't taking the long view.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
Replies
2
Views
1K
Replies
12
Views
2K
Replies
3
Views
1K
  • · Replies 16 ·
Replies
16
Views
2K
Replies
9
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K