Kinetics Review Answers
1. Pressure, temperature, pH, conductivity, color, mass
2. To find the rate we need to calculate the slope of the tangent line at t=30 minutes.
rate = −
Δ[ N 2 O 5 ]
(0.002 − 0.010)
=−
= 0.00016 mol/L min
Δt
(55 − 5)
3. use the rate equation
a. 1 Δ[ N 2 ] 1 Δ[H 2 O]
=
2 Δt
6 Δt
1
(0.27 ) = 1 Δ[H 2 O]
2
6 Δt
Δ[H 2 O]
= 0.81 mol/Ls
Δt
b.
1 Δ[ N 2 ] 1 Δ[ NH 3 ]
=
2 Δt
4 Δt
1
(0.27 ) = 1 Δ[ NH 3 ]
2
4 Δt
Δ[ NH 3 ]
= 0.54 mol/Ls
Δt
c.
1 Δ[ N 2 ] 1 Δ[O 2 ]
=
2 Δt
3 Δt
1
(0.27 ) = 1 Δ[O 2 ]
2
3 Δt
Δ[O 2 ]
= 0.405 mol/Ls
Δt
4. Surface area – an increased surface area provides more particles for collisions; more
collisions means an increase in reaction rate
Concentration – increased concentration means more particles are present; more particles
means more collisions which means an increase in reaction rate
Temperature – an increase in temperature increases the energy of the particles; increased
energy means that more of the collisions will have sufficient energy to form the activated
complex resulting in an increased reaction rate.
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5. The amount of energy required for the colliding particles to form the activated complex
6.
a.
b.
7. A catalyst lowers the activation energy required for the reaction.
8. Reaction mechanism – the complete sequence of elementary steps that make up a complex
reaction
Rate determining step – the slowest elementary step in a reaction mechanism
9.
a. 2 NO(g) + Cl2(g) → 2 NOCl(g)
b. NOCl2
c. Step 2
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10. [A]
Trial 3
Trial 2
Trial 3
Trial 2
[A] 2
[A] 0.40
=
=2
[A] 0.20
rate 0.04080
=
=4
rate 0.01020
[B]
Trial 2 [B] 0.3
=
=3
Trial 1 [B] 0.1
Trial 2 rate 0.01020
=
=3
Trial 1 rate 0.00340
[B]1
Therefore, rate = k[A] 2 [B]
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