The graph shows the Maxwell–Boltzmann energy distribution curve for a given gas at a certain temperature.

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

Which will increase the rate of reaction between calcium carbonate and hydrochloric acid?

I. an increase in temperature

II. an increase in concentration of hydrochloric acid

III. an increase in particle size of calcium carbonate

Which is the activation energy of the forward reaction?

The same amount of two gases, X and Y, are in two identical containers at the same temperature. What is the difference between the gases?

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 conditions are required for the reaction between two molecules?

I. a collision

II. E ≥ E_a

III. proper orientation

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?

What is the activation energy of the reverse reaction?

Samples of sodium carbonate powder were reacted with separate samples of excess hydrochloric acid.

Na₂CO₃ (s) + 2HCl (aq) → CO₂ (g) + 2NaCl (aq) + H₂O (l)

Reaction I: 1.0 g Na₂CO₃ (s) added to 0.50 mol dm⁻³ HCl (aq)

Reaction II: 1.0 g Na₂CO₃ (s) added to 2.0 mol dm⁻³ HCl (aq)

What is the same for reactions I and II?

What decreases the activation energy of a reaction?

Which change increases the rate of formation of hydrogen when zinc reacts with excess hydrochloric acid, assuming all other conditions remain the same?

Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

Which statements are correct?

I. The activation energy of a reaction is not affected by temperature.

II. A catalyst reduces the enthalpy change of a reaction.

III. Catalysts provide alternative reaction pathways.

The potential energy profile for the reversible reaction, X + Y → Z is shown.

Which arrow represents the activation energy for the reverse reaction, Z → X + Y, with a catalyst?

Which factors can affect the rate of reaction?

I. Particle size of solid reactant

II. Concentration of reacting solution

III. Pressure of reacting gas

The diagram shows the energy profile for a catalysed and uncatalysed reaction. Which represents the enthalpy change, ΔH, and the activation energy, E_a, for the catalysed reaction?

Excess magnesium powder was added to a beaker containing hydrochloric acid, HCl (aq).

The mass of the beaker and its contents was recorded and plotted against time (line I). Which change could give line II?

Copper catalyses the reaction between zinc and dilute sulfuric acid.

Zn(s) + H₂SO₄(aq) → ZnSO₄(aq) + H₂(g)

Why does copper affect the reaction?

100 cm³ of 10% hydrogen peroxide solution decomposes at 298 K to form water and oxygen.

H₂O₂(aq) → H₂O(l) + O₂(g)

The dotted line graph represents the volume of oxygen produced.

Which graph represents the decomposition of an equal volume of a 20% solution under the same conditions?

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

Which change does not increase the initial rate of reaction when CaCO₃(s) is added to excess HCl(aq)?

For the reaction R → P, which letter represents the activation energy for the catalysed reverse reaction?

Which conditions must be met for a reaction to take place?

I. Reactants collide with sufficient energy.

II. Reactants collide with correct orientation.

III. Reactants must be in the same state.

Which experimental methods could be used to observe the progress of the following reaction?

Cr₂O₇^2-(aq) + 6I^-(aq) + 14H⁺(aq) → 2Cr³⁺(aq) + 3I₂(aq) + 7H₂O(l)

I. Change in colour

II. Change in mass

III. Change in electrical conductivity

Graph 1 shows a plot of volume of CO₂ (g) against time for the reaction of CaCO₃ (s) with 1.00 moldm⁻³ HCl (aq). The acid is the limiting reagent and entirely covers the lumps of CaCO₃ (s).

Which set of conditions is most likely to give the data plotted in graph 2 when the same mass of CaCO₃ (s) is reacted with the same volume of HCl (aq) at the same temperature?

Which variable is best to use when determining the rate of decomposition of hydrogen peroxide? $2H_2O_2\ \left(l\right)\rightarrow_{\ }2H_2O\ \left(l\right)\ +\ O_2\ \left(g\right)$  

Which is a correct unit for expressing the rate of a reaction?

100cm³ of a 1.00 mol dm^-3 solution of hydrochloric acid is added to 2.00 g of small pieces of calcium carbonate at 20 °C. The volume of carbon dioxide produced against time is plotted to give curve P. Which change will produce curve Q, given that calcium carbonate is always the limiting reagent?

Which quantity can be changed by the use of a catalyst?

Why does the rate of a reaction increase when the temperature is increased?

I. The activation energy decreases.

II. There are more particles with energy equal to or greater than the activation energy.

III. The frequency of collisions between particles increases.

The diagram represents the Maxwell‒Boltzmann energy distribution curve of the reactants for a chemical reaction with different activation energies, and .

What is the reason why the rate of the reaction with activation energy energy E_a2 is greater?

Which change increases the rate of a chemical reaction?

Which is not affected by an increase in temperature?

Which factors can increase the rate of a chemical reaction?

I. Increasing the pressure in gaseous reactions

II. Increasing the temperature in gaseous reactions

III. Increasing the particle size of a solid in a reaction

Which statement best describes and explains the effect of a catalyst on the rate of a chemical reaction?

Which statements explain the increase in the rate of a reaction when the temperature is increased?

I. More particles have energy greater than the activation energy.

II. The frequency of collisions increases.

III. The activation energy decreases.

In which flask will the reaction between 2.0 g of magnesium carbonate and 25 cm³ 1.0 mol dm^–3 hydrochloric acid occur most rapidly?

Which statement about the kinetic theory is not correct?

Which changes increase the rate of the reaction below? C₄H₁₀ (g) + Cl₂ (g)  →  C₄H₉Cl (l) + HCl (g)

I. Increase of pressure

II. Increase of temperature

III. Removal of HCl (g)

Which of the following can increase the rate of a chemical reaction?

I. Increasing the temperature

II. Adding a catalyst

III. Increasing the concentration of reactants

Hydrochloric acid is reacted with large pieces of calcium carbonate, the reaction is then repeated using calcium carbonate powder. How does this change affect the activation energy and the collision frequency?

Which statement is true about using sulfuric acid as a catalyst in this reaction?

I. The catalyst increases the rate of reaction.

II. The catalyst lowers the activation energy for the reaction.

III. The catalyst has been consumed at the end of the chemical reaction.

What is the best definition of rate of reaction?