Chemical Kinetics
What is the reaction rate of 3A --> 2B?
-1/3 A/t = 1/2 B/t
Define a Lewis acid and base
Lewis acid: electron pair acceptor
Lewis base: electron pair donor
the reaction shifts right (spontaneous because products are favored)
Is the entropy increasing or decreasing?
4H2O (l) + O2 (g) --> 4CO2 (g) + 3 H2O (g)
increasing
A Daniell cell converts chemical energy to
electrical energy
What are the five factors that alter the rate of a reaction?
2. nature of the reactants
3. concentration of the reactants
4. temperature
5. catalyst
A weak base B has a base dissociation constant:
Kb=6.2×10−6
What is Ka?
1.6 x 10^-9
If K <1, the reaction is
nonspontaneous
For calculating delta G, S, and H of the system, what equation will you always use?
sum of products- reactants for G, H, and S
Define cathode and anode.
Cathode is being reduced, anode is being oxidized in the equation
A certain reaction is first order with respect to reactant A. The initial concentration of A is 0.800 M. After 35.0 minutes, the concentration of A decreases to 0.200 M.
0.0396 min^-1
Is NaHCO3 an acidic, basic or neutral salt?
acidic
Write the equilibrium expression of the following equation:
4NH3(g) + 5O2(g) ⇌ 4NO(g) + 6H2O(g)
Kc=[NO]^4[H2O]^6 / [NH3]^4[O2]^5
At 298 K, a reaction has:
ΔG∘=−45.0 kJ/mol
ΔS∘=−120.0 J/mol
What is ΔH?
-80.8 kJ/mol
Balance the following in acidic solution:
MnO^4− (aq) + C2O4^2− (aq) → Mn^2+ (aq)+ CO2(g)
2MnO^ 4− + 5C2O4^2−+ 16H^+ → 2Mn^2+ + 10CO2 + 8H2O
The rate constant for a reaction is k1=2.50×10−3 s^-1 at 298 K, and k2=1.85×10−2 s^-1 at 338 K. What is the activation energy?
41.9 kJ/mol
Is NH3 a lewis acid or base
Lewis base
At a certain temperature, the reaction reaches equilibrium:
A⇌B
The equilibrium constant is:
Kc=0.40
A is present at a concentration of 1.00 M. What is the equilibrium concentration?
[A]= 0.714 M
[B]= 0.286 M
At 350 K, a reaction has a standard Gibbs free energy change of:
ΔG∘=−18.5 kJ/mol
What is K
K= 580
Zn^2+ +2e− → Zn(s). E∘=−0.76V
Ag^+ +e− → Ag(s). E∘=+0.80 V
Calculate the standard cell potential.
E cell = 1.56 V
Find the rate law using the equations below:
Step 1 (fast equilibrium):
A + B ⇌ C
Step 2 (fast equilibrium):
C + B ⇌ D
Step 3 (slow):
D → E
rate= k[A][B]^2
A weak acid HA is dissolved in water:
HA ⇌ H+ + A−
A solution is prepared with an initial concentration of 0.200 M HA. At equilibrium, the pH is measured to be 2.90. Find the acid disassociation constant, Ka, for HA.
8.0 x 10^-6
A(g) + B(g) ⇌ C(g). K1=4.0
C(g) ⇌ D(g) + B(g). K2=0.50
D(g) + A(g) ⇌ E(g). K3=2.0
Find the K overall for the following reaction:
3A(g) + 2B(g) ⇌ 2E(g)
K overall = 32
In the equation S= kln(W), W represents what?
number of microstates
Fe3+ + e− → Fe2+. E∘=+0.77V
Sn2+ + 2e− → Sn(s). E∘=−0.14 V
Calculate Delta G at 298 K
Delta G= -176 kJ/mol