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) ?

Answer 1

Ans 1

Given that

Reaction rate of consumption of hydrogen -r_H2 = 0.074 M/s

reaction

N2(g) + 3H2(g) → 2NH3(g)

Relation between rates

-r_N2/1 = - r_H2/3 = r_NH3/2

Part a

rate of reaction of consumption of N2

-r_N2/1 = - r_H2/3

-r_N2 = 0.074*1/3 = 0.0246 M/s

Part b

(b) rate of reaction of formation of NH3

- r_H2/3 = r_NH3/2

r_NH3 = 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.