Skip to main content
Ch.14 - Chemical Kinetics

Chapter 14, Problem 46

From the following data for the first-order gas-phase isomerization of CH3NC at 215 C, calculate the firstorder rate constant and half-life for the reaction: Time (s) Pressure CH3nC (torr) 0 502 2000 335 5000 180 8000 95.5 12,000 41.7 15,000 22.4

Verified Solution
Video duration:
2m
This video solution was recommended by our tutors as helpful for the problem above.
1191
views
Was this helpful?

Video transcript

Hello everyone today. We are being given the falling problem. The hypothetical gas phase isomerization of A. B two B. A. At 425°C was observed. Let me have the following table here. What are its rate constant and half life if the reaction is first order. So the first thing you must know is that the rate constant is essentially Kay or negative K. So we'll have a negative slope. And to find that slope we simply have to use the equation that our slope is equal to. And we'll use these two values. For the first two values Y two minus Y. One equals X two minus X. To our pressure is in the white Xs. And our exes in our temper our time is on our X axis. So for time we'll have 1000 minus zero. And then for our pressure we will have 662 minus 89 incorporating that negative sign. We will get 1.76 times 10 to the negative four seconds To the -1 power. So that's our rate constant. As for our half life we must then use the formula that T 1/2 sub one half is equal to 0.693 over K. And that 0.693 comes from the equation itself. And when we do that we get 0.693 divided by the slope that we determined 1.76 times 10 to the negative fourth. And we get 3.94 times 10 to the third seconds. And so we have solved for our slope or our rate constant as well as our half life overall. I hope this helped, and until next time.
Related Practice
Textbook Question

As described in Exercise 14.41, the decomposition of sulfuryl chloride 1SO2Cl22 is a first-order process. The rate constant for the decomposition at 660 K is 4.5 * 10-2 s-1. (b) At what time will the partial pressure of SO2Cl2 decline to one-tenth its initial value?

1754
views
Textbook Question

The first-order rate constant for the decomposition of N2O5, 2 N2O51g2¡4 NO21g2 + O21g2, a t 70 C i s 6.82 * 10-3 s-1. Suppose we start with 0.0250 mol of N2O51g2 in a volume of 2.0 L. (a) How many moles of N2O5 will remain after 5.0 min?

2863
views
Textbook Question

The first-order rate constant for the decomposition of N2O5, 2 N2O51g2¡4 NO21g2 + O21g2, a t 70 C i s 6.82 * 10-3 s-1. Suppose we start with 0.0250 mol of N2O51g2 in a volume of 2.0 L. (c) What is the half-life of N2O5 at 70 C ?

1058
views
Textbook Question

Consider the data presented in Exercise 14.19. (c) What is the half-life for the reaction?

723
views
Textbook Question

The gas-phase decomposition of NO2, 2 NO21g2¡ 2 NO1g2 + O21g2, is studied at 383 C, giving the following data: Time (s) 3no2 4 (M) 0.0 0.100 5.0 0.017 10.0 0.0090 15.0 0.0062 20.0 0.0047 (c) Predict the reaction rates at the beginning of the reaction for initial concentrations of 0.200 M, 0.100 M, and 0.050 M NO2.

1744
views
Textbook Question

Sucrose 1C12H22O112, commonly known as table sugar, reacts in dilute acid solutions to form two simpler sugars, glucose and fructose, both of which have the formula C6H12O6. At 23 C and in 0.5 M HCl, the following data were obtained for the disappearance of sucrose: Time (min) 3C12H22o11 4 1M2 0 0.316 39 0.274 80 0.238 140 0.190 210 0.146 (a) Is the reaction first order or second order with respect to 3C12H22O114?

2567
views