Consider the reaction: N2(g) + 3H2(g) 2NH3(g). At a particular moment during the
ID: 701851 • Letter: C
Question
Consider the reaction: N2(g) + 3H2(g) 2NH3(g). At a particular moment during the reaction hydrogen is being
consumed at a rate of 0.074 M/s. At this moment:
(a) What is the rate of reaction (in M/s)? {3 points}
(b) A what rate (in M/s) is NH3 being produced? {3 points}
(c) Are these average or instantaneous rates? {1 point}
[3] A certain first-order reaction has a rate constant of 1.65 min-1 at 20°C. What is the value of the rate constant at 60°C if
the activation energy is 75.5 kJ/mol? {6 points}
[5] The first order rate constant for reaction N2O5(g) 2NO2(g) + O2(g) Is 6.82×10-3 s-1
. If the initial concentration of N2O5 is 0.258M
(a) What is the half-life. {3 points}
(b) What is the concentration of N2O5 after 130 seconds have elapsed. {4 points}
The equilibrium reaction: 2NOBr (g) 2NO(g) + Br2(g) is endothermic. For each of the following changes indicate if
the concentration of NOBr would decrease, increase, or remain the same {1 point each}
(a) Some Br2 was removed from the reaction mixture decrease, increase, remain the same
(b) The volume of the reaction vessel was increased decrease, increase, remain the same
(c) The temperature of the reaction was increased decrease, increase, remain the same
(d) A catalyst was added decrease, increase, remain the same
The following reaction has an equilibrium constant KP equal to 2.4×10-4 at 1073 K..Determine the following at this
temperature.
2H2S(g) 2H2(g) + S2(g)
(a) If the reaction favor reactants or products?
(b) KC for the reaction 2H2S(g) 2H2(g) + S2(g)?
(c) What is KP for the reaction 3H2(g) + 3/2S2(g) 3H2S(g) ?
(d) Determine the reaction quotient for a mixture consisting of 0.212 atm of H2S, 0.677 atm of H2 and 1.14 atm of S2. In which direction will the reaction proceed to reach equilibrium ?
(e) If the equilibrium partial pressures of H2S and S2 are respectively 3.14 atm and 0.107 atm, what is the equilibrium partial pressure of H2 (in atm) ?
Explanation / Answer
Ans 1
Given that
Reaction rate of consumption of hydrogen -rH2 = 0.074 M/s
reaction
N2(g) + 3H2(g) 2NH3(g)
Relation between rates
-rN2/1 = - rH2/3 = rNH3/2
Part a
rate of reaction of consumption of N2
-rN2/1 = - rH2/3
-rN2 = 0.074*1/3 = 0.0246 M/s
Part b
(b) rate of reaction of formation of NH3
- rH2/3 = rNH3/2
rNH3 = 2*0.074/3 = 0.0493 M/s
Part C
These rates are instantaneous rates because these rates have been calculated at any instant time t.
While average rates are calculated over a period of time.