Problems B
81
N 2 O 5 -> 2 NO, + - O 2
t (°C)
25.0
35.0
45.0
55.0
65.0
k
3.46 x 10' 1. 35 x 10" 4.98 x 10" 1. 50 x I0
7
4.87 x 10
7
Plot these data on semilog graph paper.
(b) Construct a graph on the plot made in (a), and determine the mathematical
equation for the relationship between k and T,
*(c) (/) Using the method of least squares, find the equation of the best-fit line
for the data as plotted in (a) above. (//) Find the correlation coefficient
and the 95% confidence intervals for both the slope and the y intercept of
the best-fit equation. (HI) On the plot made in (a), draw the line that
corresponds to the best-fit equation.
(d) Calculate the value of the activation energy for this reaction.
(e) What is the physical significance of the constant Ql
7. Regardless of how fast a chemical reaction takes place, it usually reaches an
equilibrium position at which there appears to be no further change, because
the reactants are being reformed from the products at the same rate at which
they are reacting to form the products. This position of equilibrium commonly
is characterized at a given temperature by a constant K,., called the equilibrium constant (see Chapter 16). The equilibrium constant commonly is measured at several different temperatures for a given reaction, because these
values of K e are related to the Kelvin temperature (T) at which they are
measured; the relationship is
In this equation, \H is the so-called "energy (or enthalpy) of reaction," Z is a
constant characteristic of the reaction, and R is the ideal gas constant, 1.987
cal mole"' K~'.
(a) The following data are obtained for the reaction
H, + I, -> 2 HI
t (°C)
340
K,
70.8
360
66.0
380
61.9
400
57.7
420
53.7
440
50.5
460
46.8
Plot these data on semilog graph paper,
(b) Construct a graph on the plot made in (a), and determine the mathematical
equation for the relationship between K t , and T.
*(c) (i) Using the method of least squares, find the equation of the best-fit
line for the data as plotted in (a) above, (/i) Find the correlation coefficient and the 95% confidence intervals for both the slope and the y
intercept of the best-fit equation. (iVi) On the plot made in (a), draw the
line that corresponds to the best-fit equation.
81
N 2 O 5 -> 2 NO, + - O 2
t (°C)
25.0
35.0
45.0
55.0
65.0
k
3.46 x 10' 1. 35 x 10" 4.98 x 10" 1. 50 x I0
7
4.87 x 10
7
Plot these data on semilog graph paper.
(b) Construct a graph on the plot made in (a), and determine the mathematical
equation for the relationship between k and T,
*(c) (/) Using the method of least squares, find the equation of the best-fit line
for the data as plotted in (a) above. (//) Find the correlation coefficient
and the 95% confidence intervals for both the slope and the y intercept of
the best-fit equation. (HI) On the plot made in (a), draw the line that
corresponds to the best-fit equation.
(d) Calculate the value of the activation energy for this reaction.
(e) What is the physical significance of the constant Ql
7. Regardless of how fast a chemical reaction takes place, it usually reaches an
equilibrium position at which there appears to be no further change, because
the reactants are being reformed from the products at the same rate at which
they are reacting to form the products. This position of equilibrium commonly
is characterized at a given temperature by a constant K,., called the equilibrium constant (see Chapter 16). The equilibrium constant commonly is measured at several different temperatures for a given reaction, because these
values of K e are related to the Kelvin temperature (T) at which they are
measured; the relationship is
In this equation, \H is the so-called "energy (or enthalpy) of reaction," Z is a
constant characteristic of the reaction, and R is the ideal gas constant, 1.987
cal mole"' K~'.
(a) The following data are obtained for the reaction
H, + I, -> 2 HI
t (°C)
340
K,
70.8
360
66.0
380
61.9
400
57.7
420
53.7
440
50.5
460
46.8
Plot these data on semilog graph paper,
(b) Construct a graph on the plot made in (a), and determine the mathematical
equation for the relationship between K t , and T.
*(c) (i) Using the method of least squares, find the equation of the best-fit
line for the data as plotted in (a) above, (/i) Find the correlation coefficient and the 95% confidence intervals for both the slope and the y
intercept of the best-fit equation. (iVi) On the plot made in (a), draw the
line that corresponds to the best-fit equation.