Reactivity 2. How much, how fast and how far?

Write a balanced equation for the reaction that occurs.

Calculate the amount of magnesium, in mol, that was used.

Assume the reaction in (a)(i) is the only one occurring and it goes to completion, but some product has been lost from the crucible. Deduce the percentage yield of magnesium oxide in the crucible.

Evaluate whether this, rather than the loss of product, could explain the yield found in (b)(iii).

Calculate coefficients that balance the equation for the following reaction.

__ Mg₃N₂(s) + __ H₂O (l) → __ Mg(OH)₂(s) + __ NH₃(aq)

With reference to the reaction quotient, Q, explain why the percentage yield increases as the pressure is increased at constant temperature.

Write an equation for the reaction of white phosphorus (P₄) with chlorine gas to form phosphorus trichloride (PCl₃).

Oil spills can be treated with an enzyme mixture to speed up decomposition.

Outline one factor to be considered when assessing the greenness of an enzyme mixture.

What is the sum of the integer coefficients when propene undergoes complete combustion?

__C₃H₆ (g) + __O₂ (g) → __CO₂ (g) + __H₂O (l)

A. 11

B. 17

C. 21

D. 23

State one factor considered when making green chemistry polymers.

Oil spills can be treated with an enzyme mixture to speed up decomposition.

Outline one factor to be considered when assessing the greenness of an enzyme mixture.

What is the sum of the integer coefficients when propene undergoes complete combustion?

__C₃H₆ (g) + __O₂ (g) → __CO₂ (g) + __H₂O (l)

A. 11

B. 17

C. 21

D. 23

Deduce the equation for the decomposition of guanidinium nitrate.

Calculate the total number of moles of gas produced from the decomposition of 10.0 g of guanidinium nitrate.

Calculate the number of moles of oxygen in the day 0 sample.

What volume of carbon dioxide, CO₂ (g), can be obtained by reacting 1 dm³ of methane, CH₄ (g), with 1 dm³ of oxygen, O₂ (g)?

CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l)

A. 0.5 dm³

B. 1 dm³

C. 2 dm³

D. 6 dm³

What is the sum of the coefficients when the equation is balanced with the smallest whole numbers?

__BaCl₂ (aq) + __Fe₂(SO₄)₃ (aq) → __FeCl₃ (aq) + __BaSO₄ (s)

A. 4

B. 6

C. 8

D. 9

0.10 mol of hydrochloric acid is mixed with 0.10 mol of calcium carbonate.

2HCl (aq) + CaCO₃ (s) → CaCl₂ (aq) + H₂O (l) + CO₂ (g)

Which is correct?

What is the sum of the coefficients when the equation is balanced with whole numbers?

__MnO₂ (s) + __HCl (aq) → __MnCl₂ (aq) + __H₂O (l) + __Cl₂ (g)

A.  6

B.  7

C.  8

D.  9

Write the equation for the reaction of Ca(OH)₂(aq) with hydrochloric acid, HCl (aq).

Write the equation for this reaction.

Write an equation for the reaction of white phosphorus (P₄) with chlorine gas to form phosphorus trichloride (PCl₃).

0.20 mol of magnesium is mixed with 0.10 mol of hydrochloric acid.

$\text{Mg\hspace{0.05em}(s)}+\text{2HCl} \text{(aq)}\to {\text{MgCl}}_{\text{2}} \text{(aq)}+{\text{H}}_{\text{2}} \text{(g)}$

Which is correct?

What is the sum of the coefficients when the equation is balanced with whole numbers?

__Sn(OH)₄(aq) + __NaOH (aq) → __Na₂SnO₃(aq) + __H₂O (l)

A.  4

B.  5

C.  6

D.  7

Write the equation for this reaction.

Outline a green chemistry solution for problems generated by the use of organic solvents.

Deduce the overall cell reaction including state symbols. Use section 7 of the data booklet.

What is the coefficient of $\text{HCl}$ (aq) when the equation is balanced using the smallest possible whole numbers?

$\text{\_\_CuO\hspace{0.05em}(s)+ \_\_HCl} {\text{(aq) → \_\_CuCl}}_{\text{2}} {\text{(aq) + \_\_H}}_{\text{2}}\text{O} \text{(l)}$

A.  1

B.  2

C.  3

D.  4

What is the coefficient for H⁺ when the equation below is balanced?

__Pb (s) + __NO₃⁻ (aq) + __H⁺ (aq) → __Pb²⁺ (aq) + __NO (g) + __H₂O (l)

A.  2

B.  4

C.  6

D.  8

Calculate the amount, in mol, of sulfur dioxide produced when 500.0 g of lignite undergoes combustion.

S (s) + O₂ (g) → SO₂ (g)

How many moles of carbon dioxide are produced by the complete combustion of 7.0 g of ethene, C₂H₄ (g)?

M_r = 28

A.  0.25

B.  0.5

C.  0.75

D.  1.0

Write a balanced equation for the reaction that occurs.

Calculate the amount of magnesium, in mol, that was used.

Assume the reaction in (a)(i) is the only one occurring and it goes to completion, but some product has been lost from the crucible. Deduce the percentage yield of magnesium oxide in the crucible.

Evaluate whether this, rather than the loss of product, could explain the yield found in (b)(iii).

Calculate coefficients that balance the equation for the following reaction.

__ Mg₃N₂(s) + __ H₂O (l) → __ Mg(OH)₂(s) + __ NH₃(aq)

Write a balanced equation for the reaction that occurs.

Calculate the amount of magnesium, in mol, that was used.

Assume the reaction in (a)(i) is the only one occurring and it goes to completion, but some product has been lost from the crucible. Deduce the percentage yield of magnesium oxide in the crucible.

Evaluate whether this, rather than the loss of product, could explain the yield found in (b)(iii).

Calculate coefficients that balance the equation for the following reaction.

__ Mg₃N₂(s) + __ H₂O (l) → __ Mg(OH)₂(s) + __ NH₃(aq)

With reference to the reaction quotient, Q, explain why the percentage yield increases as the pressure is increased at constant temperature.

With reference to the reaction quotient, Q, explain why the percentage yield increases as the pressure is increased at constant temperature.

Write an equation for the reaction of white phosphorus (P₄) with chlorine gas to form phosphorus trichloride (PCl₃).

Write an equation for the reaction of white phosphorus (P₄) with chlorine gas to form phosphorus trichloride (PCl₃).

Oil spills can be treated with an enzyme mixture to speed up decomposition.

Outline one factor to be considered when assessing the greenness of an enzyme mixture.

What is the sum of the integer coefficients when propene undergoes complete combustion?

__C₃H₆ (g) + __O₂ (g) → __CO₂ (g) + __H₂O (l)

A. 11

B. 17

C. 21

D. 23

State one factor considered when making green chemistry polymers.

Oil spills can be treated with an enzyme mixture to speed up decomposition.

Outline one factor to be considered when assessing the greenness of an enzyme mixture.

What is the sum of the integer coefficients when propene undergoes complete combustion?

__C₃H₆ (g) + __O₂ (g) → __CO₂ (g) + __H₂O (l)

A. 11

B. 17

C. 21

D. 23

Deduce the equation for the decomposition of guanidinium nitrate.

Calculate the total number of moles of gas produced from the decomposition of 10.0 g of guanidinium nitrate.

Deduce the equation for the decomposition of guanidinium nitrate.

Calculate the total number of moles of gas produced from the decomposition of 10.0 g of guanidinium nitrate.

Calculate the number of moles of oxygen in the day 0 sample.

Calculate the number of moles of oxygen in the day 0 sample.

What volume of carbon dioxide, CO₂ (g), can be obtained by reacting 1 dm³ of methane, CH₄ (g), with 1 dm³ of oxygen, O₂ (g)?

CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l)

A. 0.5 dm³

B. 1 dm³

C. 2 dm³

D. 6 dm³

What is the sum of the coefficients when the equation is balanced with the smallest whole numbers?

__BaCl₂ (aq) + __Fe₂(SO₄)₃ (aq) → __FeCl₃ (aq) + __BaSO₄ (s)

A. 4

B. 6

C. 8

D. 9

0.10 mol of hydrochloric acid is mixed with 0.10 mol of calcium carbonate.

2HCl (aq) + CaCO₃ (s) → CaCl₂ (aq) + H₂O (l) + CO₂ (g)

Which is correct?

What is the sum of the coefficients when the equation is balanced with whole numbers?

__MnO₂ (s) + __HCl (aq) → __MnCl₂ (aq) + __H₂O (l) + __Cl₂ (g)

A.  6

B.  7

C.  8

D.  9

Write the equation for the reaction of Ca(OH)₂(aq) with hydrochloric acid, HCl (aq).

Write the equation for the reaction of Ca(OH)₂(aq) with hydrochloric acid, HCl (aq).

Write the equation for this reaction.

Write the equation for this reaction.

Write an equation for the reaction of white phosphorus (P₄) with chlorine gas to form phosphorus trichloride (PCl₃).

Write an equation for the reaction of white phosphorus (P₄) with chlorine gas to form phosphorus trichloride (PCl₃).

0.20 mol of magnesium is mixed with 0.10 mol of hydrochloric acid.

$\text{Mg\hspace{0.05em}(s)}+\text{2HCl} \text{(aq)}\to {\text{MgCl}}_{\text{2}} \text{(aq)}+{\text{H}}_{\text{2}} \text{(g)}$

Which is correct?

What is the sum of the coefficients when the equation is balanced with whole numbers?

__Sn(OH)₄(aq) + __NaOH (aq) → __Na₂SnO₃(aq) + __H₂O (l)

A.  4

B.  5

C.  6

D.  7

Write the equation for this reaction.

Write the equation for this reaction.

Outline a green chemistry solution for problems generated by the use of organic solvents.

Deduce the overall cell reaction including state symbols. Use section 7 of the data booklet.

Deduce the overall cell reaction including state symbols. Use section 7 of the data booklet.

What is the coefficient of $\text{HCl}$ (aq) when the equation is balanced using the smallest possible whole numbers?

$\text{\_\_CuO\hspace{0.05em}(s)+ \_\_HCl} {\text{(aq) → \_\_CuCl}}_{\text{2}} {\text{(aq) + \_\_H}}_{\text{2}}\text{O} \text{(l)}$

A.  1

B.  2

C.  3

D.  4

What is the coefficient for H⁺ when the equation below is balanced?

__Pb (s) + __NO₃⁻ (aq) + __H⁺ (aq) → __Pb²⁺ (aq) + __NO (g) + __H₂O (l)

A.  2

B.  4

C.  6

D.  8

Calculate the amount, in mol, of sulfur dioxide produced when 500.0 g of lignite undergoes combustion.

S (s) + O₂ (g) → SO₂ (g)

Calculate the amount, in mol, of sulfur dioxide produced when 500.0 g of lignite undergoes combustion.

S (s) + O₂ (g) → SO₂ (g)

How many moles of carbon dioxide are produced by the complete combustion of 7.0 g of ethene, C₂H₄ (g)?

M_r = 28

A.  0.25

B.  0.5

C.  0.75

D.  1.0

Outline two differences between heterogeneous and homogeneous catalysts.

Outline, giving a reason, the effect of a catalyst on a reaction.

What is the activation energy according to the following plot of the linear form of the Arrhenius equation?

Arrhenius equation: $k=A{e}^{\frac{\mathit{-}Ea}{RT}}$.

A.  $E_a=\frac{2\times 8.31}{0.06}$

B.  $E_a=\frac{-2\times 8.31}{0.06}$

C.  $E_a=e^{\frac{2\times 8.31}{0.06}}$

D.  $E_a=e^{\frac{-2\times 8.31}{0.06}}$

Deduce the order of reaction with respect to hydrogen.

Deduce the rate expression for the reaction.

Calculate the value of the rate constant stating its units.

Outline, giving a reason, the effect of a catalyst on a reaction.

On the axes, sketch Maxwell–Boltzmann energy distribution curves for the reacting species at two temperatures T₁ and T₂, where T₂ > T₁.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Two more trials (2 and 3) were carried out. The results are given below.

Determine the rate equation for the reaction and its overall order, using your answer from (b)(i).

Rate equation: 

Overall order: 

Additional experiments were carried out at an elevated temperature. On the axes below, sketch Maxwell–Boltzmann energy distribution curves at two temperatures T₁ and T₂, where T₂ > T₁.

Apart from a greater frequency of collisions, explain, by annotating your graphs in (b)(iii), why an increased temperature causes the rate of reaction to increase.

Explain the action of metals as heterogeneous catalysts.

Suggest two reasons why oil decomposes faster at the surface of the ocean than at greater depth.

Deduce how the rate of reaction at t = 2 would compare to the initial rate.

It has been suggested that the reaction occurs as a two-step process:

Step 1: N₂O (g) → N₂ (g) + O (g)

Step 2: N₂O (g) + O (g) → N₂ (g) + O₂ (g)

Explain how this could support the observed rate expression.

The graph below shows the Maxwell–Boltzmann distribution of molecular energies at a particular temperature.

The rate at which dinitrogen monoxide decomposes is significantly increased by a metal oxide catalyst.

Annotate and use the graph to outline why a catalyst has this effect.

The dotted line represents the formation of oxygen, O₂ (g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Several reactions of calcium carbonate with dilute hydrochloric acid are carried out at the same temperature.

CaCO₃ (s) + 2HCl (aq) → CaCl₂ (aq) + H₂O (l) + CO₂ (g)

Which reaction has the greatest rate?

Which statement is correct about a catalyst?

A. It decreases the activation energy of the forward reaction but not the reverse.

B. It increases the proportion of products to reactants in an equilibrium.

C. It decreases the enthalpy change of the reaction.

D. It changes the mechanism of the reaction.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Additional experiments were carried out at an elevated temperature. On the axes below, sketch Maxwell–Boltzmann energy distribution curves at two temperatures T₁ and T₂, where T₂ > T₁.

Apart from a greater frequency of collisions, explain, by annotating your graphs in (b)(ii), why an increased temperature causes the rate of reaction to increase.

The graph below shows the Maxwell–Boltzmann distribution of molecular energies at a particular temperature.

The rate at which dinitrogen monoxide decomposes is significantly increased by a metal oxide catalyst.

Annotate and use the graph to outline why a catalyst has this effect.

Explain the action of metals as heterogeneous catalysts.

The dotted line represents the formation of oxygen, O₂(g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Several reactions of calcium carbonate with dilute hydrochloric acid are carried out at the same temperature.

CaCO₃ (s) + 2HCl (aq) → CaCl₂ (aq) + H₂O (l) + CO₂ (g)

Which reaction has the greatest rate?

Outline two differences between heterogeneous and homogeneous catalysts.

Suggest two reasons why oil decomposes faster at the surface of the ocean than at greater depth.

Explain why the rate of reaction of limestone with nitric acid decreases and reaches zero over the period of five days.

A reaction proceeds by the following mechanism:

step 1: $\mathrm{A}+\mathrm{A}\to \mathrm{B}$
step 2: $\mathrm{B}+\mathrm{C}\to \mathrm{D}$

Which rate equation is consistent with this mechanism?

A.  Rate = k[B]²[C]

B.  Rate = k[A]²[B][C]

C.  Rate = k[A]²

D.  Rate = k[A][C]

Write the rate expression for this reaction.

Calculate the value of the rate constant, k, giving its units.

Which statements about bond strength and activation energy are correct for this reaction?

${\mathrm{CH}}_4 \left(\mathrm{g}\right)+2{\mathrm{O}}_2 \left(\mathrm{g}\right)\to {\mathrm{CO}}_2 \left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O} \left(\mathrm{l}\right)$      $∆H^{⦵}=-891 \mathrm{kJ}$

K_c for 2N₂O (g) $\rightleftharpoons$ 2N₂ (g) + O₂ (g) is 7.3 × 10³⁴.

What is K_c for the following reaction, at the same temperature?

N₂ (g) + $\frac{1}{2}$O₂ (g) $\rightleftharpoons$ N₂O (g)

A. 7.3 × 10³⁴

B. $\frac{1}{\sqrt{7.3\times {10}^{34}}}$

C. $\frac{2}{7.3\times {10}^{34}}$

D. $\frac{1}{2\times 7.3\times {10}^{34}}$

What is the order with respect to each reactant?

2NO (g) + Cl₂ (g) → 2NOCl (g)

Nitrogen monoxide reacts with oxygen gas to form nitrogen dioxide.

The following experimental data was obtained.

Deduce the partial order of reaction with respect to nitrogen monoxide and oxygen.

Which arrow shows the activation energy of the uncatalysed forward reaction for this equilibrium?

$2{\mathrm{SO}}_2 \left(\mathrm{g}\right)+{\mathrm{O}}_2 \left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{SO}}_3 \left(\mathrm{g}\right)$     $∆H=-196 \mathrm{kJ} {\mathrm{mol}}^{-1}$

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Sketch an energy profile for the decomposition of calcium carbonate based on your answer to b(i), labelling the axes and activation energy, E_a.

Determine the volume, in dm³, of 0.015 mol dm⁻³ calcium hydroxide solution needed to neutralize 35.0 cm³ of 0.025 mol dm⁻³ HCl (aq).

Which change causes the greatest increase in the initial rate of reaction between nitric acid and magnesium?

2HNO₃(aq) + Mg (s) → Mg(NO₃)₂ (aq) + H₂(g)

What is the intercept on the y-axis when a graph of lnk is plotted against $\frac{1}{T}$ on the x-axis?

$\ln k=-\frac{E_a}{RT}+\ln A$

A.  lnA

B.  $-\frac{E_{\mathrm{a}}}{R}$

C.  $-\frac{R}{E_{\mathrm{a}}}$

D.   $E_{\mathrm{a}}$

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Deduce the relationship between the concentration of N₂O₅ and the rate of reaction.

What are the units of the rate constant, $k$, if the rate equation is $\mathrm{Rate}=k\left[\mathrm{A}\right]{\left[\mathrm{B}\right]}^2$?

A.  $\mathrm{mol} {\mathrm{dm}}^{-3} {\mathrm{s}}^{-1}$

B.  ${\mathrm{dm}}^3 {\mathrm{mol}}^{-1 }{\mathrm{s}}^{-1}$

C.  ${\mathrm{dm}}^6 {\mathrm{mol}}^{-2 }{\mathrm{s}}^{-1}$

D.  ${\mathrm{dm}}^9 {\mathrm{mol}}^{-3 }{\mathrm{s}}^{-1}$

Determine the rate expression for the reaction.

Determine the value and unit of the rate constant using the rate expression in (a).

Which graph represents the relationship between the rate constant, $k$, and temperature, $T$, in kelvin?

Which change does not increase the rate of this reaction?

${\mathrm{CuCO}}_3 \left(\mathrm{s}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4 \left(\mathrm{aq}\right)\to {\mathrm{CuSO}}_4 \left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O} \left(\mathrm{l}\right)+{\mathrm{CO}}_2 \left(\mathrm{g}\right)$

A.  Increasing the particle size of the ${\mathrm{CuCO}}_3$

B.  Increasing the temperature

C.  Increasing the concentration of ${\mathrm{H}}_2{\mathrm{SO}}_4 \left(\mathrm{aq}\right)$

D.  Stirring the reaction mixture

A student was investigating rates of reaction. In which of the following cases would a colorimeter show a change in absorbance?

A.  KBr (aq) + Cl₂(aq)

B.  Cu (s) + Na₂SO₄(aq)

C.  HCl (aq) + NaOH (aq)

D.  (CH₃)₃COH (aq) + K₂Cr₂O₇(aq)

The rate equation for a reaction is:

rate = k[A][B]

Which mechanism is consistent with this rate equation?

A.  2A $\rightleftharpoons$ I       Fast
     I + B → P    Slow

B.  A + B $\rightleftharpoons$ I   Fast
     I + A → P    Slow

C.  A → I          Slow
     I + B → P    Fast

D.  B $\rightleftharpoons$ I         Fast
     I + A → P    Slow

The activation energy of a reaction can be obtained from the rate constant, k, and the absolute temperature, $\text{T}$. Which graph of these quantities produces a straight line?

A.  k against $\text{T}$

B.  k against $\frac{1}{\text{T}}$

C.  ln k against $\text{T}$

D.  ln k against $\frac{1}{\text{T}}$

The exothermic reaction $\text{I}$₂ (g) + 3Cl₂ (g) $\rightleftharpoons$ 2$\text{I}$Cl₃ (g) is at equilibrium in a fixed volume. What is correct about the reaction quotient, Q, and shift in position of equilibrium the instant temperature is raised?

A.   Q > K, equilibrium shifts right towards products.

B.   Q > K, equilibrium shifts left towards reactants.

C.   Q < K, equilibrium shifts right towards products.

D.   Q < K, equilibrium shifts left towards reactants.

Which substance is the reducing agent in the given reaction?

H⁺ (aq) + 2H₂O (l) + 2MnO₄⁻ (aq) + 5SO₂ (g) → 2Mn²⁺ (aq) + 5HSO₄⁻ (aq)

A.  H⁺

B.  H₂O

C.  MnO₄⁻

D.  SO₂

Data is given for the reaction 2X₂ (g) + Y₂ (g) → 2X₂Y (g).

What rate equation can be inferred from the data?

A.  Rate = k [X₂] [Y₂]

B.  Rate = k [X₂]² [Y₂]

C.  Rate = k [X₂]² [Y₂]⁰

D.  Rate = k [X₂]² [Y₂]²

Outline two differences between heterogeneous and homogeneous catalysts.

Outline, giving a reason, the effect of a catalyst on a reaction.

Outline, giving a reason, the effect of a catalyst on a reaction.

What is the activation energy according to the following plot of the linear form of the Arrhenius equation?

Arrhenius equation: $k=A{e}^{\frac{\mathit{-}Ea}{RT}}$.

A.  $E_a=\frac{2\times 8.31}{0.06}$

B.  $E_a=\frac{-2\times 8.31}{0.06}$

C.  $E_a=e^{\frac{2\times 8.31}{0.06}}$

D.  $E_a=e^{\frac{-2\times 8.31}{0.06}}$

Deduce the order of reaction with respect to hydrogen.

Deduce the rate expression for the reaction.

Calculate the value of the rate constant stating its units.

Deduce the order of reaction with respect to hydrogen.

Deduce the rate expression for the reaction.

Calculate the value of the rate constant stating its units.

Outline, giving a reason, the effect of a catalyst on a reaction.

On the axes, sketch Maxwell–Boltzmann energy distribution curves for the reacting species at two temperatures T₁ and T₂, where T₂ > T₁.

Outline, giving a reason, the effect of a catalyst on a reaction.

On the axes, sketch Maxwell–Boltzmann energy distribution curves for the reacting species at two temperatures T₁ and T₂, where T₂ > T₁.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Two more trials (2 and 3) were carried out. The results are given below.

Determine the rate equation for the reaction and its overall order, using your answer from (b)(i).

Rate equation: 

Overall order: 

Additional experiments were carried out at an elevated temperature. On the axes below, sketch Maxwell–Boltzmann energy distribution curves at two temperatures T₁ and T₂, where T₂ > T₁.

Apart from a greater frequency of collisions, explain, by annotating your graphs in (b)(iii), why an increased temperature causes the rate of reaction to increase.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Two more trials (2 and 3) were carried out. The results are given below.

Determine the rate equation for the reaction and its overall order, using your answer from (b)(i).

Rate equation: 

Overall order: 

Additional experiments were carried out at an elevated temperature. On the axes below, sketch Maxwell–Boltzmann energy distribution curves at two temperatures T₁ and T₂, where T₂ > T₁.

Apart from a greater frequency of collisions, explain, by annotating your graphs in (b)(iii), why an increased temperature causes the rate of reaction to increase.

Explain the action of metals as heterogeneous catalysts.

Suggest two reasons why oil decomposes faster at the surface of the ocean than at greater depth.

Deduce how the rate of reaction at t = 2 would compare to the initial rate.

It has been suggested that the reaction occurs as a two-step process:

Step 1: N₂O (g) → N₂ (g) + O (g)

Step 2: N₂O (g) + O (g) → N₂ (g) + O₂ (g)

Explain how this could support the observed rate expression.

The graph below shows the Maxwell–Boltzmann distribution of molecular energies at a particular temperature.

The rate at which dinitrogen monoxide decomposes is significantly increased by a metal oxide catalyst.

Annotate and use the graph to outline why a catalyst has this effect.

Deduce how the rate of reaction at t = 2 would compare to the initial rate.

It has been suggested that the reaction occurs as a two-step process:

Step 1: N₂O (g) → N₂ (g) + O (g)

Step 2: N₂O (g) + O (g) → N₂ (g) + O₂ (g)

Explain how this could support the observed rate expression.

The graph below shows the Maxwell–Boltzmann distribution of molecular energies at a particular temperature.

The rate at which dinitrogen monoxide decomposes is significantly increased by a metal oxide catalyst.

Annotate and use the graph to outline why a catalyst has this effect.

The dotted line represents the formation of oxygen, O₂ (g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Several reactions of calcium carbonate with dilute hydrochloric acid are carried out at the same temperature.

CaCO₃ (s) + 2HCl (aq) → CaCl₂ (aq) + H₂O (l) + CO₂ (g)

Which reaction has the greatest rate?

Which statement is correct about a catalyst?

A. It decreases the activation energy of the forward reaction but not the reverse.

B. It increases the proportion of products to reactants in an equilibrium.

C. It decreases the enthalpy change of the reaction.

D. It changes the mechanism of the reaction.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Additional experiments were carried out at an elevated temperature. On the axes below, sketch Maxwell–Boltzmann energy distribution curves at two temperatures T₁ and T₂, where T₂ > T₁.

Apart from a greater frequency of collisions, explain, by annotating your graphs in (b)(ii), why an increased temperature causes the rate of reaction to increase.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Additional experiments were carried out at an elevated temperature. On the axes below, sketch Maxwell–Boltzmann energy distribution curves at two temperatures T₁ and T₂, where T₂ > T₁.

Apart from a greater frequency of collisions, explain, by annotating your graphs in (b)(ii), why an increased temperature causes the rate of reaction to increase.

The graph below shows the Maxwell–Boltzmann distribution of molecular energies at a particular temperature.

The rate at which dinitrogen monoxide decomposes is significantly increased by a metal oxide catalyst.

Annotate and use the graph to outline why a catalyst has this effect.

The graph below shows the Maxwell–Boltzmann distribution of molecular energies at a particular temperature.

The rate at which dinitrogen monoxide decomposes is significantly increased by a metal oxide catalyst.

Annotate and use the graph to outline why a catalyst has this effect.

Explain the action of metals as heterogeneous catalysts.

The dotted line represents the formation of oxygen, O₂(g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Several reactions of calcium carbonate with dilute hydrochloric acid are carried out at the same temperature.

CaCO₃ (s) + 2HCl (aq) → CaCl₂ (aq) + H₂O (l) + CO₂ (g)

Which reaction has the greatest rate?

Outline two differences between heterogeneous and homogeneous catalysts.

Suggest two reasons why oil decomposes faster at the surface of the ocean than at greater depth.

Explain why the rate of reaction of limestone with nitric acid decreases and reaches zero over the period of five days.

A reaction proceeds by the following mechanism:

step 1: $\mathrm{A}+\mathrm{A}\to \mathrm{B}$
step 2: $\mathrm{B}+\mathrm{C}\to \mathrm{D}$

Which rate equation is consistent with this mechanism?

A.  Rate = k[B]²[C]

B.  Rate = k[A]²[B][C]

C.  Rate = k[A]²

D.  Rate = k[A][C]

Write the rate expression for this reaction.

Calculate the value of the rate constant, k, giving its units.

Write the rate expression for this reaction.

Calculate the value of the rate constant, k, giving its units.

Which statements about bond strength and activation energy are correct for this reaction?

${\mathrm{CH}}_4 \left(\mathrm{g}\right)+2{\mathrm{O}}_2 \left(\mathrm{g}\right)\to {\mathrm{CO}}_2 \left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O} \left(\mathrm{l}\right)$      $∆H^{⦵}=-891 \mathrm{kJ}$

K_c for 2N₂O (g) $\rightleftharpoons$ 2N₂ (g) + O₂ (g) is 7.3 × 10³⁴.

What is K_c for the following reaction, at the same temperature?

N₂ (g) + $\frac{1}{2}$O₂ (g) $\rightleftharpoons$ N₂O (g)

A. 7.3 × 10³⁴

B. $\frac{1}{\sqrt{7.3\times {10}^{34}}}$

C. $\frac{2}{7.3\times {10}^{34}}$

D. $\frac{1}{2\times 7.3\times {10}^{34}}$

What is the order with respect to each reactant?

2NO (g) + Cl₂ (g) → 2NOCl (g)

Nitrogen monoxide reacts with oxygen gas to form nitrogen dioxide.

The following experimental data was obtained.

Deduce the partial order of reaction with respect to nitrogen monoxide and oxygen.

Nitrogen monoxide reacts with oxygen gas to form nitrogen dioxide.

The following experimental data was obtained.

Deduce the partial order of reaction with respect to nitrogen monoxide and oxygen.

Which arrow shows the activation energy of the uncatalysed forward reaction for this equilibrium?

$2{\mathrm{SO}}_2 \left(\mathrm{g}\right)+{\mathrm{O}}_2 \left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{SO}}_3 \left(\mathrm{g}\right)$     $∆H=-196 \mathrm{kJ} {\mathrm{mol}}^{-1}$

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Sketch an energy profile for the decomposition of calcium carbonate based on your answer to b(i), labelling the axes and activation energy, E_a.

Determine the volume, in dm³, of 0.015 mol dm⁻³ calcium hydroxide solution needed to neutralize 35.0 cm³ of 0.025 mol dm⁻³ HCl (aq).

Sketch an energy profile for the decomposition of calcium carbonate based on your answer to b(i), labelling the axes and activation energy, E_a.

Determine the volume, in dm³, of 0.015 mol dm⁻³ calcium hydroxide solution needed to neutralize 35.0 cm³ of 0.025 mol dm⁻³ HCl (aq).

Which change causes the greatest increase in the initial rate of reaction between nitric acid and magnesium?

2HNO₃(aq) + Mg (s) → Mg(NO₃)₂ (aq) + H₂(g)

What is the intercept on the y-axis when a graph of lnk is plotted against $\frac{1}{T}$ on the x-axis?

$\ln k=-\frac{E_a}{RT}+\ln A$

A.  lnA

B.  $-\frac{E_{\mathrm{a}}}{R}$

C.  $-\frac{R}{E_{\mathrm{a}}}$

D.   $E_{\mathrm{a}}$

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Deduce the relationship between the concentration of N₂O₅ and the rate of reaction.

Deduce the relationship between the concentration of N₂O₅ and the rate of reaction.

What are the units of the rate constant, $k$, if the rate equation is $\mathrm{Rate}=k\left[\mathrm{A}\right]{\left[\mathrm{B}\right]}^2$?

A.  $\mathrm{mol} {\mathrm{dm}}^{-3} {\mathrm{s}}^{-1}$

B.  ${\mathrm{dm}}^3 {\mathrm{mol}}^{-1 }{\mathrm{s}}^{-1}$

C.  ${\mathrm{dm}}^6 {\mathrm{mol}}^{-2 }{\mathrm{s}}^{-1}$

D.  ${\mathrm{dm}}^9 {\mathrm{mol}}^{-3 }{\mathrm{s}}^{-1}$

Determine the rate expression for the reaction.

Determine the value and unit of the rate constant using the rate expression in (a).

Determine the rate expression for the reaction.

Determine the value and unit of the rate constant using the rate expression in (a).

Which graph represents the relationship between the rate constant, $k$, and temperature, $T$, in kelvin?

Which change does not increase the rate of this reaction?

${\mathrm{CuCO}}_3 \left(\mathrm{s}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4 \left(\mathrm{aq}\right)\to {\mathrm{CuSO}}_4 \left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O} \left(\mathrm{l}\right)+{\mathrm{CO}}_2 \left(\mathrm{g}\right)$

A.  Increasing the particle size of the ${\mathrm{CuCO}}_3$

B.  Increasing the temperature

C.  Increasing the concentration of ${\mathrm{H}}_2{\mathrm{SO}}_4 \left(\mathrm{aq}\right)$

D.  Stirring the reaction mixture

A student was investigating rates of reaction. In which of the following cases would a colorimeter show a change in absorbance?

A.  KBr (aq) + Cl₂(aq)

B.  Cu (s) + Na₂SO₄(aq)

C.  HCl (aq) + NaOH (aq)

D.  (CH₃)₃COH (aq) + K₂Cr₂O₇(aq)

The rate equation for a reaction is:

rate = k[A][B]

Which mechanism is consistent with this rate equation?

A.  2A $\rightleftharpoons$ I       Fast
     I + B → P    Slow

B.  A + B $\rightleftharpoons$ I   Fast
     I + A → P    Slow

C.  A → I          Slow
     I + B → P    Fast

D.  B $\rightleftharpoons$ I         Fast
     I + A → P    Slow

The activation energy of a reaction can be obtained from the rate constant, k, and the absolute temperature, $\text{T}$. Which graph of these quantities produces a straight line?

A.  k against $\text{T}$

B.  k against $\frac{1}{\text{T}}$

C.  ln k against $\text{T}$

D.  ln k against $\frac{1}{\text{T}}$

The exothermic reaction $\text{I}$₂ (g) + 3Cl₂ (g) $\rightleftharpoons$ 2$\text{I}$Cl₃ (g) is at equilibrium in a fixed volume. What is correct about the reaction quotient, Q, and shift in position of equilibrium the instant temperature is raised?

A.   Q > K, equilibrium shifts right towards products.

B.   Q > K, equilibrium shifts left towards reactants.

C.   Q < K, equilibrium shifts right towards products.

D.   Q < K, equilibrium shifts left towards reactants.

Which substance is the reducing agent in the given reaction?

H⁺ (aq) + 2H₂O (l) + 2MnO₄⁻ (aq) + 5SO₂ (g) → 2Mn²⁺ (aq) + 5HSO₄⁻ (aq)

A.  H⁺

B.  H₂O

C.  MnO₄⁻

D.  SO₂

Data is given for the reaction 2X₂ (g) + Y₂ (g) → 2X₂Y (g).

What rate equation can be inferred from the data?

A.  Rate = k [X₂] [Y₂]

B.  Rate = k [X₂]² [Y₂]

C.  Rate = k [X₂]² [Y₂]⁰

D.  Rate = k [X₂]² [Y₂]²

Deduce the expression for the equilibrium constant, K_c, for this equation.

With reference to the reaction quotient, Q, explain why the percentage yield increases as the pressure is increased at constant temperature.

Determine the enthalpy change, ΔH, for the Haber–Bosch process, in kJ. Use Section 11 of the data booklet.

Demonstrate that your answer to (b)(i) is consistent with the effect of an increase in temperature on the percentage yield, as shown in the graph.

Calculate the value of the equilibrium constant, K, at 298 K. Use sections 1 and 2 of the data booklet.

What is the strongest acid in the equation below?

H₃AsO₄ + H₂O $\rightleftharpoons$ H₂AsO₄⁻ + H₃O⁺      K_c = 4.5 × 10⁻⁴

A.  H₃AsO₄

B.  H₂O

C.  H₂AsO₄⁻

D.  H₃O⁺

0.50 mol of ${\text{I}}_2$ (g) and 0.50 mol of Br₂(g) are placed in a closed flask. The following equilibrium is established.

${\text{I}}_2$(g) + Br₂(g) $\rightleftharpoons$ 2$\text{I}$Br (g)

The equilibrium mixture contains 0.80 mol of $\text{I}$Br (g). What is the value of K_c?

A.  0.64

B.  1.3

C.  2.6

D.  64

The dissociation of citric acid is an endothermic process. State the effect on the hydrogen ion concentration, [H⁺], and on the equilibrium constant, of increasing the temperature.

State the equilibrium constant expression, K_c, for this reaction.

When a bottle of carbonated water is opened, these equilibria are disturbed.

State, giving a reason, how a decrease in pressure affects the position of Equilibrium (1).

Predict, referring to Equilibrium (2), how the added sodium hydrogencarbonate affects the pH.(Assume pressure and temperature remain constant.)

Phenylethene is manufactured from benzene and ethene in a two-stage process. The overall reaction can be represented as follows with ΔG^θ = +10.0 kJ mol⁻¹ at 298 K.

Calculate the equilibrium constant for the overall conversion at 298 K, using section 1 of the data booklet.

State the equilibrium constant expression, K_c, for this reaction.

Comment on why peracetic acid, CH3COOOH, is always sold in solution with ethanoic acid and hydrogen peroxide.

H₂O₂ (aq) + CH₃COOH (aq) ⇌ CH₃COOOH (aq) + H₂O (l)

Calculate the concentration of H₃PO₄ if 25.00 cm³ is completely neutralised by the addition of 28.40 cm³ of 0.5000 mol dm⁻³ NaOH.

When a bottle of carbonated water is opened, these equilibria are disturbed.

State, giving a reason, how a decrease in pressure affects the position of Equilibrium (1).

Predict, referring to Equilibrium (2), how the added sodium hydrogencarbonate affects the pH.(Assume pressure and temperature remain constant.)

Comment on why peracetic acid, CH₃COOOH, is always sold in solution with ethanoic acid and hydrogen peroxide.

H₂O₂ (aq) + CH₃COOH (aq) $\rightleftharpoons$ CH₃COOOH (aq) + H₂O (l)

Consider the following equilibrium reaction.

2N₂O (g) + O₂ (g) $\rightleftharpoons$ 4NO (g)        ΔH = +16 kJ

Which change will move the equilibrium to the right?

A. Decrease in pressure

B. Decrease in temperature

C. Increase in [NO]

D. Decrease in [O₂]

A solution of bleach can be made by reacting chlorine gas with a sodium hydroxide solution.

Cl2 (g) + 2NaOH (aq) $\rightleftharpoons$ NaOCl (aq) + NaCl (aq) + H₂O (l)

Suggest, with reference to Le Châtelier’s principle, why it is dangerous to mix vinegar and bleach together as cleaners.

What is the equilibrium constant expression for the following equation?

2NO₂ (g) + F₂ (g) $\rightleftharpoons$ 2NO₂F (g)

A. $\frac{2[\text{N}{\text{O}}_2\text{F]}}{2[\text{N}{\text{O}}_2]+[{\text{F}}_2]}$

B. $\frac{2[\text{N}{\text{O}}_2\text{F]}}{2[\text{N}{\text{O}}_2][{\text{F}}_2]}$

C. $\frac{{[\text{N}{\text{O}}_2\text{]}}^2\text{[}{\text{F}}_2\text{]}}{{[\text{N}{\text{O}}_2\text{F}]}^2}$

D. $\frac{{[\text{N}{\text{O}}_2\text{F]}}^2}{{[\text{N}{\text{O}}_2]}^2[{\text{F}}_2]}$

The dissociation of citric acid is an endothermic process. State the effect on the hydrogen ion concentration, [H⁺], and on K_a, of increasing the temperature.

Calculate the standard Gibbs free energy change, $\mathrm{\Delta }{G}^{\text{θ}}$, in kJ mol⁻¹, for the first dissociation of citric acid at 298 K, using section 1 of the data booklet.

Calculate the concentration of H₃PO₄ if 25.00 cm³ is completely neutralised by the addition of 28.40 cm³ of 0.5000 mol dm⁻³ NaOH.

Consider the following equilibrium reaction:

2SO₂(g) + O₂(g) $\rightleftharpoons$ 2SO₃(g)

State and explain how the equilibrium would be affected by increasing the volume of the reaction container at a constant temperature.

What effect does increasing both pressure and temperature have on the equilibrium constant, K_c?

N₂ (g) + 3H₂ (g) $\rightleftharpoons$ 2NH₃ (g)           ΔH = −45.9 kJ

A.  Decreases

B.  Increases

C.  Remains constant

D.  Cannot be predicted as effects are opposite

What is correct when temperature increases in this reaction at equilibrium?

$2\mathrm{NOCl} \left(\mathrm{g}\right)\rightleftharpoons 2\mathrm{NO} \left(\mathrm{g}\right)+{\mathrm{Cl}}_2 \left(\mathrm{g}\right)$    $∆H^{⦵}=+75.5 \mathrm{kJ}$

K_c for 2N₂O (g) $\rightleftharpoons$ 2N₂ (g) + O₂ (g) is 7.3 × 10³⁴.

What is K_c for the following reaction, at the same temperature?

N₂ (g) + $\frac{1}{2}$O₂ (g) $\rightleftharpoons$ N₂O (g)

A. 7.3 × 10³⁴

B. $\frac{1}{\sqrt{7.3\times {10}^{34}}}$

C. $\frac{1}{7.3\times {10}^{34}}$

D. $\frac{1}{2\times 7.3\times {10}^{34}}$

Which changes produce the greatest increase in the percentage conversion of methane?

CH₄(g) + H₂O (g) $\rightleftharpoons$ CO (g) + 3H₂(g)

State the equilibrium constant expression, K_c, for this reaction.

Sulfur dioxide reacts with oxygen to form sulfur trioxide.

2SO₂ (g) + O₂ (g) $\rightleftharpoons$ 2SO₃ (g)           ΔH = −197 kJ

Which change increases the value of K_c?

A.  increasing the temperature

B.  decreasing the temperature

C.  decreasing [SO₂ (g)]

D.  decreasing [SO₃ (g)]

What is the intercept on the y-axis when a graph of lnk is plotted against $\frac{1}{T}$ on the x-axis?

$\ln k=-\frac{E_a}{RT}+\ln A$

A.  lnA

B.  $-\frac{E_{\mathrm{a}}}{R}$

C.  $-\frac{R}{E_{\mathrm{a}}}$

D.   $E_{\mathrm{a}}$

State the equilibrium constant expression, K_c, for the reaction above.

SO₂ (g), O₂(g) and SO₃(g) are mixed and allowed to reach equilibrium at 600 °C.

Determine the value of K_c at 600 °C.

At equilibrium, the concentrations of chlorine and iodine are both 0.02 mol dm^–3.

$\frac{1}{2}$Cl₂ (g) + $\frac{1}{2}$${\text{I}}_2$ (g) $\rightleftharpoons$ $\text{I}$Cl (g)       K_c = 454

What is the concentration of iodine monochloride, $\text{I}$Cl?

A.  $\frac{454}{0.02}$

B.  $454\times 0.02$

C.  $\frac{454}{0.04}$

D.  $454\times 0.04$

$\frac{1}{2}$Cl₂(g) + $\frac{1}{2}{\text{I}}_2$(g) $\rightleftharpoons$ $\text{I}$Cl (g)    K_c = 454

What is the K_c value for the reaction below?

2 $\text{I}$Cl (g) $\rightleftharpoons$ Cl₂(g) + ${\text{I}}_{\text{2}}$(g)

A.  $2\times 454$

B.  $\frac{1}{2\times 454}$

C.  ${454}^2$

D.  $\frac{1}{{454}^2}$

The equilibrium 2H₂ (g) + N₂(g) $\rightleftharpoons$ N₂H₄(g) has an equilibrium constant, K, at 150 °C. 

What is the equilibrium constant at 150 °C, for the reverse reaction?

N₂H₄(g) $\rightleftharpoons$ 2H₂ (g) + N₂(g)

A.  K

B.  K⁻¹

C.  −K

D.  2K

A reversible reaction has a reaction quotient, Q, of 4.5 and equilibrium constant, K_c, of 6.2.

2A (g) $\rightleftharpoons$ A₂(g)

Which statement describes the reaction at this time?

A.  The system has reached equilibrium.

B.  The rate of the forward reaction is greater than the rate of the reverse reaction.

C.  The concentration of reactant is greater than the concentration of product.

D.  At equilibrium, the concentration of reactant is greater than the concentration of product.

The exothermic reaction $\text{I}$₂ (g) + 3Cl₂ (g) $\rightleftharpoons$ 2$\text{I}$Cl₃ (g) is at equilibrium in a fixed volume. What is correct about the reaction quotient, Q, and shift in position of equilibrium the instant temperature is raised?

A.   Q > K, equilibrium shifts right towards products.

B.   Q > K, equilibrium shifts left towards reactants.

C.   Q < K, equilibrium shifts right towards products.

D.   Q < K, equilibrium shifts left towards reactants.

Which substance is the reducing agent in the given reaction?

H⁺ (aq) + 2H₂O (l) + 2MnO₄⁻ (aq) + 5SO₂ (g) → 2Mn²⁺ (aq) + 5HSO₄⁻ (aq)

A.  H⁺

B.  H₂O

C.  MnO₄⁻

D.  SO₂

For the reaction $\text{I}$₂(g) + 3Cl₂ (g) $\rightleftharpoons$ 2$\text{I}$Cl₃ (g) at a certain temperature, the equilibrium concentrations are (in mol dm⁻³):

[$\text{I}$₂] = 0.20, [Cl₂] = 0.20, [$\text{I}$Cl₃] = 2.0

What is the value of K_c?

A.  0.25

B.  50

C.  2500

D.  5000

Which of these changes would shift the equilibrium to the right?

[Co(H₂O)₆]²⁺ (aq) + 4Cl⁻ (aq) $\rightleftharpoons$ [CoCl₄]²⁻ (aq) + 6H₂O (l)

I.   Addition of 0.01 M HCl
II.  Addition of concentrated HCl
III. Evaporation of water

A.  I and II only

B.  I and III only

C.  II and III only

D.  I, II and III

Deduce the expression for the equilibrium constant, K_c, for this equation.

With reference to the reaction quotient, Q, explain why the percentage yield increases as the pressure is increased at constant temperature.

Determine the enthalpy change, ΔH, for the Haber–Bosch process, in kJ. Use Section 11 of the data booklet.

Demonstrate that your answer to (b)(i) is consistent with the effect of an increase in temperature on the percentage yield, as shown in the graph.

Calculate the value of the equilibrium constant, K, at 298 K. Use sections 1 and 2 of the data booklet.

Deduce the expression for the equilibrium constant, K_c, for this equation.

With reference to the reaction quotient, Q, explain why the percentage yield increases as the pressure is increased at constant temperature.

Determine the enthalpy change, ΔH, for the Haber–Bosch process, in kJ. Use Section 11 of the data booklet.

Demonstrate that your answer to (b)(i) is consistent with the effect of an increase in temperature on the percentage yield, as shown in the graph.

Calculate the value of the equilibrium constant, K, at 298 K. Use sections 1 and 2 of the data booklet.

What is the strongest acid in the equation below?

H₃AsO₄ + H₂O $\rightleftharpoons$ H₂AsO₄⁻ + H₃O⁺      K_c = 4.5 × 10⁻⁴

A.  H₃AsO₄

B.  H₂O

C.  H₂AsO₄⁻

D.  H₃O⁺

0.50 mol of ${\text{I}}_2$ (g) and 0.50 mol of Br₂(g) are placed in a closed flask. The following equilibrium is established.

${\text{I}}_2$(g) + Br₂(g) $\rightleftharpoons$ 2$\text{I}$Br (g)

The equilibrium mixture contains 0.80 mol of $\text{I}$Br (g). What is the value of K_c?

A.  0.64

B.  1.3

C.  2.6

D.  64

The dissociation of citric acid is an endothermic process. State the effect on the hydrogen ion concentration, [H⁺], and on the equilibrium constant, of increasing the temperature.

The dissociation of citric acid is an endothermic process. State the effect on the hydrogen ion concentration, [H⁺], and on the equilibrium constant, of increasing the temperature.

State the equilibrium constant expression, K_c, for this reaction.

State the equilibrium constant expression, K_c, for this reaction.

When a bottle of carbonated water is opened, these equilibria are disturbed.

State, giving a reason, how a decrease in pressure affects the position of Equilibrium (1).

Predict, referring to Equilibrium (2), how the added sodium hydrogencarbonate affects the pH.(Assume pressure and temperature remain constant.)

When a bottle of carbonated water is opened, these equilibria are disturbed.

State, giving a reason, how a decrease in pressure affects the position of Equilibrium (1).

Predict, referring to Equilibrium (2), how the added sodium hydrogencarbonate affects the pH.(Assume pressure and temperature remain constant.)

Phenylethene is manufactured from benzene and ethene in a two-stage process. The overall reaction can be represented as follows with ΔG^θ = +10.0 kJ mol⁻¹ at 298 K.

Calculate the equilibrium constant for the overall conversion at 298 K, using section 1 of the data booklet.

Phenylethene is manufactured from benzene and ethene in a two-stage process. The overall reaction can be represented as follows with ΔG^θ = +10.0 kJ mol⁻¹ at 298 K.

Calculate the equilibrium constant for the overall conversion at 298 K, using section 1 of the data booklet.

State the equilibrium constant expression, K_c, for this reaction.

State the equilibrium constant expression, K_c, for this reaction.

Comment on why peracetic acid, CH3COOOH, is always sold in solution with ethanoic acid and hydrogen peroxide.

H₂O₂ (aq) + CH₃COOH (aq) ⇌ CH₃COOOH (aq) + H₂O (l)

Comment on why peracetic acid, CH3COOOH, is always sold in solution with ethanoic acid and hydrogen peroxide.

H₂O₂ (aq) + CH₃COOH (aq) ⇌ CH₃COOOH (aq) + H₂O (l)

Calculate the concentration of H₃PO₄ if 25.00 cm³ is completely neutralised by the addition of 28.40 cm³ of 0.5000 mol dm⁻³ NaOH.

Calculate the concentration of H₃PO₄ if 25.00 cm³ is completely neutralised by the addition of 28.40 cm³ of 0.5000 mol dm⁻³ NaOH.

When a bottle of carbonated water is opened, these equilibria are disturbed.

State, giving a reason, how a decrease in pressure affects the position of Equilibrium (1).

Predict, referring to Equilibrium (2), how the added sodium hydrogencarbonate affects the pH.(Assume pressure and temperature remain constant.)

When a bottle of carbonated water is opened, these equilibria are disturbed.

State, giving a reason, how a decrease in pressure affects the position of Equilibrium (1).

Predict, referring to Equilibrium (2), how the added sodium hydrogencarbonate affects the pH.(Assume pressure and temperature remain constant.)

Comment on why peracetic acid, CH₃COOOH, is always sold in solution with ethanoic acid and hydrogen peroxide.

H₂O₂ (aq) + CH₃COOH (aq) $\rightleftharpoons$ CH₃COOOH (aq) + H₂O (l)

Comment on why peracetic acid, CH₃COOOH, is always sold in solution with ethanoic acid and hydrogen peroxide.

H₂O₂ (aq) + CH₃COOH (aq) $\rightleftharpoons$ CH₃COOOH (aq) + H₂O (l)

Consider the following equilibrium reaction.

2N₂O (g) + O₂ (g) $\rightleftharpoons$ 4NO (g)        ΔH = +16 kJ

Which change will move the equilibrium to the right?

A. Decrease in pressure

B. Decrease in temperature

C. Increase in [NO]

D. Decrease in [O₂]

A solution of bleach can be made by reacting chlorine gas with a sodium hydroxide solution.

Cl2 (g) + 2NaOH (aq) $\rightleftharpoons$ NaOCl (aq) + NaCl (aq) + H₂O (l)

Suggest, with reference to Le Châtelier’s principle, why it is dangerous to mix vinegar and bleach together as cleaners.

A solution of bleach can be made by reacting chlorine gas with a sodium hydroxide solution.

Cl2 (g) + 2NaOH (aq) $\rightleftharpoons$ NaOCl (aq) + NaCl (aq) + H₂O (l)

Suggest, with reference to Le Châtelier’s principle, why it is dangerous to mix vinegar and bleach together as cleaners.

What is the equilibrium constant expression for the following equation?

2NO₂ (g) + F₂ (g) $\rightleftharpoons$ 2NO₂F (g)

A. $\frac{2[\text{N}{\text{O}}_2\text{F]}}{2[\text{N}{\text{O}}_2]+[{\text{F}}_2]}$

B. $\frac{2[\text{N}{\text{O}}_2\text{F]}}{2[\text{N}{\text{O}}_2][{\text{F}}_2]}$

C. $\frac{{[\text{N}{\text{O}}_2\text{]}}^2\text{[}{\text{F}}_2\text{]}}{{[\text{N}{\text{O}}_2\text{F}]}^2}$

D. $\frac{{[\text{N}{\text{O}}_2\text{F]}}^2}{{[\text{N}{\text{O}}_2]}^2[{\text{F}}_2]}$

The dissociation of citric acid is an endothermic process. State the effect on the hydrogen ion concentration, [H⁺], and on K_a, of increasing the temperature.

Calculate the standard Gibbs free energy change, $\mathrm{\Delta }{G}^{\text{θ}}$, in kJ mol⁻¹, for the first dissociation of citric acid at 298 K, using section 1 of the data booklet.

The dissociation of citric acid is an endothermic process. State the effect on the hydrogen ion concentration, [H⁺], and on K_a, of increasing the temperature.

Calculate the standard Gibbs free energy change, $\mathrm{\Delta }{G}^{\text{θ}}$, in kJ mol⁻¹, for the first dissociation of citric acid at 298 K, using section 1 of the data booklet.

Calculate the concentration of H₃PO₄ if 25.00 cm³ is completely neutralised by the addition of 28.40 cm³ of 0.5000 mol dm⁻³ NaOH.

Calculate the concentration of H₃PO₄ if 25.00 cm³ is completely neutralised by the addition of 28.40 cm³ of 0.5000 mol dm⁻³ NaOH.

Consider the following equilibrium reaction:

2SO₂(g) + O₂(g) $\rightleftharpoons$ 2SO₃(g)

State and explain how the equilibrium would be affected by increasing the volume of the reaction container at a constant temperature.

Consider the following equilibrium reaction:

2SO₂(g) + O₂(g) $\rightleftharpoons$ 2SO₃(g)

State and explain how the equilibrium would be affected by increasing the volume of the reaction container at a constant temperature.

What effect does increasing both pressure and temperature have on the equilibrium constant, K_c?

N₂ (g) + 3H₂ (g) $\rightleftharpoons$ 2NH₃ (g)           ΔH = −45.9 kJ

A.  Decreases

B.  Increases

C.  Remains constant

D.  Cannot be predicted as effects are opposite

What is correct when temperature increases in this reaction at equilibrium?

$2\mathrm{NOCl} \left(\mathrm{g}\right)\rightleftharpoons 2\mathrm{NO} \left(\mathrm{g}\right)+{\mathrm{Cl}}_2 \left(\mathrm{g}\right)$    $∆H^{⦵}=+75.5 \mathrm{kJ}$

K_c for 2N₂O (g) $\rightleftharpoons$ 2N₂ (g) + O₂ (g) is 7.3 × 10³⁴.

What is K_c for the following reaction, at the same temperature?

N₂ (g) + $\frac{1}{2}$O₂ (g) $\rightleftharpoons$ N₂O (g)

A. 7.3 × 10³⁴

B. $\frac{1}{\sqrt{7.3\times {10}^{34}}}$

C. $\frac{1}{7.3\times {10}^{34}}$

D. $\frac{1}{2\times 7.3\times {10}^{34}}$

Which changes produce the greatest increase in the percentage conversion of methane?

CH₄(g) + H₂O (g) $\rightleftharpoons$ CO (g) + 3H₂(g)

State the equilibrium constant expression, K_c, for this reaction.

State the equilibrium constant expression, K_c, for this reaction.

Sulfur dioxide reacts with oxygen to form sulfur trioxide.

2SO₂ (g) + O₂ (g) $\rightleftharpoons$ 2SO₃ (g)           ΔH = −197 kJ

Which change increases the value of K_c?

A.  increasing the temperature

B.  decreasing the temperature

C.  decreasing [SO₂ (g)]

D.  decreasing [SO₃ (g)]

What is the intercept on the y-axis when a graph of lnk is plotted against $\frac{1}{T}$ on the x-axis?

$\ln k=-\frac{E_a}{RT}+\ln A$

A.  lnA

B.  $-\frac{E_{\mathrm{a}}}{R}$

C.  $-\frac{R}{E_{\mathrm{a}}}$

D.   $E_{\mathrm{a}}$

State the equilibrium constant expression, K_c, for the reaction above.

SO₂ (g), O₂(g) and SO₃(g) are mixed and allowed to reach equilibrium at 600 °C.

Determine the value of K_c at 600 °C.

State the equilibrium constant expression, K_c, for the reaction above.

SO₂ (g), O₂(g) and SO₃(g) are mixed and allowed to reach equilibrium at 600 °C.

Determine the value of K_c at 600 °C.

At equilibrium, the concentrations of chlorine and iodine are both 0.02 mol dm^–3.

$\frac{1}{2}$Cl₂ (g) + $\frac{1}{2}$${\text{I}}_2$ (g) $\rightleftharpoons$ $\text{I}$Cl (g)       K_c = 454

What is the concentration of iodine monochloride, $\text{I}$Cl?

A.  $\frac{454}{0.02}$

B.  $454\times 0.02$

C.  $\frac{454}{0.04}$

D.  $454\times 0.04$

$\frac{1}{2}$Cl₂(g) + $\frac{1}{2}{\text{I}}_2$(g) $\rightleftharpoons$ $\text{I}$Cl (g)    K_c = 454

What is the K_c value for the reaction below?

2 $\text{I}$Cl (g) $\rightleftharpoons$ Cl₂(g) + ${\text{I}}_{\text{2}}$(g)

A.  $2\times 454$

B.  $\frac{1}{2\times 454}$

C.  ${454}^2$

D.  $\frac{1}{{454}^2}$

The equilibrium 2H₂ (g) + N₂(g) $\rightleftharpoons$ N₂H₄(g) has an equilibrium constant, K, at 150 °C. 

What is the equilibrium constant at 150 °C, for the reverse reaction?

N₂H₄(g) $\rightleftharpoons$ 2H₂ (g) + N₂(g)

A.  K

B.  K⁻¹

C.  −K

D.  2K

A reversible reaction has a reaction quotient, Q, of 4.5 and equilibrium constant, K_c, of 6.2.

2A (g) $\rightleftharpoons$ A₂(g)

Which statement describes the reaction at this time?

A.  The system has reached equilibrium.

B.  The rate of the forward reaction is greater than the rate of the reverse reaction.

C.  The concentration of reactant is greater than the concentration of product.

D.  At equilibrium, the concentration of reactant is greater than the concentration of product.

The exothermic reaction $\text{I}$₂ (g) + 3Cl₂ (g) $\rightleftharpoons$ 2$\text{I}$Cl₃ (g) is at equilibrium in a fixed volume. What is correct about the reaction quotient, Q, and shift in position of equilibrium the instant temperature is raised?

A.   Q > K, equilibrium shifts right towards products.

B.   Q > K, equilibrium shifts left towards reactants.

C.   Q < K, equilibrium shifts right towards products.

D.   Q < K, equilibrium shifts left towards reactants.

Which substance is the reducing agent in the given reaction?

H⁺ (aq) + 2H₂O (l) + 2MnO₄⁻ (aq) + 5SO₂ (g) → 2Mn²⁺ (aq) + 5HSO₄⁻ (aq)

A.  H⁺

B.  H₂O

C.  MnO₄⁻

D.  SO₂

For the reaction $\text{I}$₂(g) + 3Cl₂ (g) $\rightleftharpoons$ 2$\text{I}$Cl₃ (g) at a certain temperature, the equilibrium concentrations are (in mol dm⁻³):

[$\text{I}$₂] = 0.20, [Cl₂] = 0.20, [$\text{I}$Cl₃] = 2.0

What is the value of K_c?

A.  0.25

B.  50

C.  2500

D.  5000

Which of these changes would shift the equilibrium to the right?

[Co(H₂O)₆]²⁺ (aq) + 4Cl⁻ (aq) $\rightleftharpoons$ [CoCl₄]²⁻ (aq) + 6H₂O (l)

I.   Addition of 0.01 M HCl
II.  Addition of concentrated HCl
III. Evaporation of water

A.  I and II only

B.  I and III only

C.  II and III only

D.  I, II and III