1. The decomposition of sulfuryl chloride (SO2Cl2) is a first-order process. The
ID: 1024002 • Letter: 1
Question
1. The decomposition of sulfuryl chloride (SO2Cl2) is a first-order process. The rate constant for the decomposition at 660 K is 4.5 10-2 s-1.
(a) If we begin with an initial SO2Cl2 pressure of 325 torr, what is the pressure of this substance after 69 s? ____________torr
(b) At what time will the pressure of SO2Cl2 decline to one eighth its initial value? __________________s
By what factor will the pressure of sulfuryl chloride decrease after 8 half lives? Note: The answer wants this value: (325 torr)/value = final pressure after decay ________value
2. The rate constants of some reactions double with every 10 degree rise in temperature. Assume that a reaction takes place at 260 K and 270 K. What must the activation energy be for the rate constant to double as described? ______________kJ/mol
Explanation / Answer
The equation for first order reaction can be represented as
-ln (1-XA)= Kt, where XA= conversion = PA/PAO, where PA= partial pressure of A at 69 sec, PAO= 325 Torr
k= rate constant = 4.5*10-2/sec
-ln (1-XA)= 4.5*10-2*69=3.105
1-XA = 0.0448
Unconveeted = 1-XA
1-PA/PAO= 0.0448
Pressure remaining/ 325= 0.0448
Pressure remaining = 0.0448*325=14.56 Torr
b) given PA= 1/8PAO
-ln (1-1/8)= 4.5*10-2*t
t= 2.9 sec
3. Half life for 1st order reaction =0.693/K =0.693/4.5*10-2 = 15.4 seconds.
Eight half lives means, time =8*15.4 seconds=123.2second
lnPA= Ln(325)- 4.5*10-2*123.2, PA= 1.27 Torr
PA/PAO= 1.27/325= 0.003908
4. The relation between temperatures T1 and T2 , rate constants K1 and K2 , activation energy E is given by
ln(K2/K1)= (Ea/R)*(1/T1-1/T2) given K2/K1=2 T1= 260 and T2= 270 K
ln2= (Ea/8.314)*(1/260-1/270)
Ea= 40455.04 Kj/mol= 40.455 KJ/mol
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.