Question 1
Two reactions are shown.
Reaction 1: N2(g) + 3H2(g) ⇌ 2NH3(g)
Reaction 2: 2O3(g) ⇌ 3O2(g)
In reaction 1, a finely powdered iron catalyst is used.
In reaction 2, a vaporised tetrachloromethane catalyst in ultraviolet light is used.
Which statement about the catalysts used is correct?
both reaction 1 and reaction 2 use a heterogeneous catalyst
both reaction 1 and reaction 2 use a homogeneous catalyst
reaction 1 uses a heterogeneous catalyst and reaction 2 uses a homogeneous catalyst
reaction 1 uses a homogeneous catalyst and reaction 2 uses a heterogeneous catalyst
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Question 2
Hydrogen ions catalyse the hydrolysis of esters.
Which statement is correct?
the hydrogen ions act as a heterogeneous catalyst
the hydrogen ions are in the same phase as the reactants
the hydrogen ions are used up in the reaction
the hydrogen ions have no effect on the activation energy of the reaction
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Question 3
The equation shows the hydrolysis of a bromoalkane.
RBr + OH- ➔ ROH + Br-
The rate equation is rate = k[RBr]
RBr is most likely to be
bromomethane
2-bromopropane
1-bromo-2-methylpropane
2-bromo-2-methylpropane
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Question 4
A reactant Q is converted into two products.
Which of these graphs shows that this reaction is first order with respect to Q?
graph 1
graph 2
graph 3
graph 4
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Question 5
To determine the activation energy, Ea , for a reaction, a graph was plotted of ln k against 1/T, where k is the rate constant.
The Arrhenius equation is
The gradient of the graph is equal to
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Question 6
Which statement about the rate determining step of a reaction is correct?
It is the fast step
It cannot involve a catalyst
It does not involve zero order reagents
It is always between two first-order reagents
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Question 7
Nitrogen dioxide reacts with carbon monoxide as in the equation below.
NO2 + CO ➔ NO + CO2
The mechanism is:
NO2 + NO2 ➔ NO + NO3 Slow
NO3 + CO ➔ NO2 + CO2 Fast
Which expression is the correct rate equation?
rate = k[NO2][CO]
rate = k[NO2]2[CO]
rate = k[CO]
rate = k[NO2]2
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Question 8
A student plots ln k (y-axis) against 1/T (in K-1) for a reaction. The student gets a straight line graph that corresponds to the Arrhenius equation:
Which statement is correct?
the intercept on the x-axis is ln A
the intercept on the y-axis is ln A
the slope is Ea
the slope is Ea/R
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Question 9
A graph is plotted of ln k against 1/T.
(k = rate constant, T = temperature in K)
The gradient has the numerical value of -55,000.
What is the activation energy, in kJ mol-1?
+1.5 × 10-7
+2.22 × 10-6
+6.62
+457
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Question 10
The equation for the reaction of ICl and H2 is shown below.
2ICl(g) + H2(g) ➔ 2HCl(g) + I2(g)
The rate constant k for this reaction is 1.63 × 10-6 dm3 mol-1 s-1.
What is the overall order of the reaction?
0
1
2
3
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Question 11
Solutions of two compounds, W and X, react together in the presence of a soluble catalyst, Y, as shown in the equation
2W + X ➔ Z
When the concentrations of W, X and Y are all doubled, the rate of reaction increases by a factor of four.
Which is a possible rate equation for this reaction?
rate = k [W]2[X]
rate = k [W]2[Y]
rate = k [X][Y]
rate = k [X][Z]
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Question 12
The rate equation for the hydrogenation of ethene:
C2H4(g) + H2(g) ➔ C2H6(g)
is rate = k[C2H4][H2].
At a fixed temperature, the reaction mixture is compressed to triple the original pressure.
What is the factor by which the rate of reaction changes?
6
9
12
27
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Question 13
The rate expression for the reaction between X and Y is
rate = k [X]2[Y]
Which statement is correct?
the rate constant has units mol-1 dm3 s-1
the rate of the reaction is halved if the concentration of X is halved and the concentration of Y is doubled
the rate increases by a factor of 16 if the concentration of X is tripled and the concentration of Y is doubled
the rate constant is independent of temperature
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Question 14
What are the units of the rate constant for a third order reaction?
mol dm-3 s-1
mol-1 dm-3 s-1
mol2 dm-6 s-1
mol-2 dm6 s-1
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Question 15
The results of an investigation of the reaction between P and Q are shown in this table.
The rate equation is: rate = k[P][Q]2
What is the initial concentration of Q in experiment 2?
0.167
0.333
0.408
0.612
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