Question

1:

Consider the following set of data ccollected for a reaction of the form

A --> products.

time (seconds)	[A] (M)
0	1.000
10	0.641
20	0.472
30	0.373
40	0.309
50	0.263

A: What is the average rate of the reaction for the first 10 seconds?

rate = ___ M/s

B: What is the average rate of the reaction between 30 and 40 seconds?

rate = ___ M/s

2:

Consider the dimerization of C₄H₆:

2 C₄H₆ --> C₈H₁₂

for which the following data re collected:

time (sec)	[C4H6] (M)
0	1.00x10-2
1600	5.04x10-3
3200	3.37x10-3
4800	2.53x10-3
6200	2.08x10-3

A:

Using empirical kinetics methods, determine the order of the reaction rate law.

a		2nd order
b		1st order
c		0th order
d		The order can not be determined from this data.

B:
Based on the data above, calculate the concentration of C₄H₆ at 7,885 seconds.

concentration of C₄H₆ = ___ x 10^-3 M

3:

Consider the following data for the catalytic decomposition of NH₃:

NH3 (M)	rate (M/hour)
1.0 x 10-3	1.5 x 10-6
2.0 x 10-3	1.5 x 10-6
3.0 x 10-3	1.5 x 10-6

This reaction is ___ in NH₃.

a.

2nd

b.

1st

c.

0th

d.

can not be determined

4:

1. Consider the following initial rate data for the reaction

   A + B --> C

   run	[A]0	[B]0	rate (M/s)
   1	0.450	0.100	0.0602
   2	0.225	0.100	0.0301
   3	0.225	0.275	0.2344

   The rate law suggested by this data is ___ .

   	a	rate = [A][B]
   	b	rate = [A][B]2
   	c	rate = [A]2[B]
   	d	rate = [A]2[B]2

5:

Consider the following concentration data taken every 10 seconds for a particular reaction which will be used for this and the next three problems):

A --> products

time (sec)	[A] (M)	time (sec)	[A] (M)
0	1.000	100	0.610
10	0.940	110	0.587
20	0.887	120	0.566
30	0.839	130	0.546
40	0.796	140	0.527
50	0.758	150	0.510
60	0.723	160	0.494
70	0.691	170	0.479
80	0.661	180	0.465
90	0.635	190	0.451
100	0.610	200	0.439

A:

What is the half-life of the reaction when the concentration of [A] is 1.000 M?

	a	About 105 seconds
	b	About 45 seconds
	c	About 175 seconds
	d	About 155 seconds

B:

Based on the data above, the half-life ____ as the initial concentration decreased, implying that the reaction is ___ order with respect to A.

	a	decreased, 0th
	b	remained constant, 1st
	c	The question cannot be answered using the given data.
	d	increased, 2nd

C:

Based on the data above, the rate constant for this reaction has a value of ___.

a.		0.004 sec-1
b		0.0064 M-1 sec-1
c		The question cannot be answered using the data provided.
d		0.0027 M sec-1

6:

Consider the reaction:

CO(g) + NO₂(g) ⟶ CO₂₍g) + NO(g)

for which the rate law for the reaction is

rate = k[NO₂][CO]

How with the rate be affected if the total pressure is increased from 0.450 atm to 0.900 atm?

7:

The half-life for the first order decay of ³²P by beta particle emission is 14.29 days. How many days will it take for 90% of the ³²P to decay in a sample?

8:

For a given reaction, the rate constant doubles with the temperature increases from 22.5 ^oC to 38.7 ^oC. What is the activation energy (E_a) for the reaction?

E_a = ___ kJ/mol

9:

Consider this data for this and the following problem:

For the gas-phase dissociation reaction A --> B + C, The following data is collected at 298 K:

time (sec)	total pressure (atm)
0	1.000
1000	1.359
3000	1.627
5000	1.737
9000	1.834

PART A:

1. Determine the partial pressure of A at each time.
2. Make a graph of ln(P_A) and 1/P_A vs time in order to determine the order of the reaction and the rate constant.

The rate law for this reaction is given by...

PART B:

Based on the data above, calculate the total pressure at 8,263 seconds.

10:

At 473 K, for the reversible elementary reaction

2 NOCL-->K1 2 NO + CL2

            <--K-1

k1=7.8×10−2 M-1 s-1 and k−1=4.7×102 M-2 s-1. A sample of NOCl is placed in a container and heated to 473 K. When the system comes to equilibrium, [NOCl] is found to be 0.11 mol/L .What is the equilibrium concentration of [NO]?

Hint: Equilibrium is achieved when the forward reaction rate is equal to the reverse reaction rate.

[NO] = ___ M

Answer 1

1) Average rate of reaction over a time interval is given by ,the change is the concentration (∆A) divided by the change in time(∆t).

Here, the reactant A is getting consumed so the change in concentration (∆A) of reactant is negative .so to make the RATE OF REACTION a positive quantity we put minus sign before it.