Exam code: YCH11
The decomposition of ammonia is catalysed by tungsten metal.
2NH3 (g) N2 (g) + 3H2 (g)
This reaction has zero order kinetics.
What is the rate equation for this reaction?
rate = k
rate = k[NH3]
rate = k[NH3]2
rate = k[N2][H2]3
What are the units of the rate constant, k, for this zero order reaction?
no units
s−1
mol dm−3 s−1
dm3 mol−1 s−1
Which of these graphs represents this zero order reaction?
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The halogenoalkane 2-bromo-2-methylbutane was hydrolysed with sodium hydroxide solution, NaOH (aq).
Which suggestion about the mechanism of this reaction is correct?
|
| Type of mechanism | Number of steps in mechanism |
□ | A | SN2 | one |
□ | B | SN2 | two |
□ | C | SN1 | one |
□ | D | SN1 | two |
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Nitrogen monoxide and hydrogen react together to form nitrogen and water.
2NO + 2H2 → N2 + 2H2O
The steps in the mechanism of the reaction are
Step 1 | 2NO ⇌ N2O2 | fast |
Step 2 | N2O2 + H2 → N2O + H2O | slow |
Step 3 | N2O + H2 → N2 + H2O | fast |
Which statement about the reaction is correct?
Step 3 is the rate determining step and the overall order is 2
Step 3 is the rate determining step and the overall order is 4
Step 2 is the rate determining step and the overall order is 2
Step 2 is the rate determining step and the overall order is 3
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The rate equation for a reaction is
rate = k [A]2 [B]0
The initial rate of reaction is 9.0 × 10−5 mol dm−3 s−1 when [A] = 0.30 mol dm−3 and [B] = 0.20 mol dm−3.
What is the value of the rate constant in dm3 mol−1 s−1?
8.1 × 10−6
3.0 × 10−4
1.0 × 10−3
5.0 × 10−3
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Calcium carbonate decomposes on heating according to the equilibrium shown.
CaCO3 (s) ⇌ CaO (s) + CO2 (g)
Which of these is the expression for Kc for this equilibrium?
Kc = [CO2]
Kc =
Kc =
Kc =
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Sulfur dioxide reacts with oxygen in the Contact process to form sulfur trioxide.
2SO2 (g) + O2 (g) ⇌ 2SO3 (g) ΔH° = −197 kJ mol⁻¹
Which of these changes would increase the value of Kp?
Adding a catalyst
Decreasing the temperature
Decreasing the total pressure
Increasing the temperature
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A reaction is monitored by measuring the concentration of reactant A at regular time intervals. The results are shown on the concentration–time graph.
What is the order of the reaction with respect to A, and what are the units of the rate constant k?
Order | Units of k | |
|---|---|---|
A | 0 | s-1 |
B | 0 | mol dm-3 s-1 |
C | 1 | s-1 |
D | 1 | mol dm-3 s-1 |
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Which of these monomers forms an addition polymer?
1,2-diaminoethane
benzene-1,4-dicarboxylic acid
chloroethene
ethane-1,2-diol
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The Arrhenius equation can be shown as
In
A graph is plotted of ln k against 1/T for a reaction. The activation energy, Ea , of this reaction equals
– gradient ÷ R
+ gradient ÷ R
– gradient × R
+ gradient × R
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Propanone reacts with iodine in the presence of a catalyst of dilute hydrochloric acid. The reaction occurs in aqueous solution.
CH3COCH3 + I2 → CH3COCH2I + HI
The rate equation for this reaction is
rate = k[CH3COCH3][H+]
Which is a possible mechanism for the reaction?
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