Chemistry 5070 · O Level
Rate of reaction
100 practice questions on Rate of reaction, with worked solutions and instant marking.
From the graph, curve 1 was produced by monitoring the decomposition of $100\,\text{cm}^3$ of $1.0\,\text{mol dm}^{-3}$ hydrogen peroxide solution, catalysed by manganese(IV) oxide. $2\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_2$ Which change to the original experimental conditions would generate curve 2?
May/June 2015
Limestone reacts with hydrochloric acid. Which reaction condition can be changed without affecting the rate of reaction?
May/June 2015
On the graph, curve 1 was produced by monitoring the decomposition of $100\,\text{cm}^3$ of $1.0\,\text{mol dm}^{-3}$ hydrogen peroxide solution, with manganese(IV) oxide as the catalyst. $2\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_2$ Which change to the initial experimental conditions would give curve 2?
May/June 2015
A learner uses the setup shown to explore how marble $(\text{CaCO}_3)$ reacts with hydrochloric acid.
May/June 2015
The diagram illustrates the energy profile of a chemical reaction, displayed both with and without a catalyst. Which energy change corresponds to the activation energy for the catalysed reaction?
May/June 2016
The diagram illustrates the apparatus used to determine the rate of reaction between calcium carbonate and dilute hydrochloric acid. The mass of the flask and its contents is recorded at regular time intervals. Which graph correctly indicates how the mass of the flask and contents varies with time?
May/June 2016
Which process does not make use of a catalyst?
May/June 2016
The diagram illustrates an energy profile for a chemical reaction, shown both in the presence of a catalyst and in its absence. Which energy change represents the activation energy for the catalysed reaction?
May/June 2016
Which process does not use a catalyst?
May/June 2016
On heating potassium chlorate(V), it decomposes and oxygen is released.
May/June 2016
Magnesium carbonate and dilute hydrochloric acid react to produce magnesium chloride, carbon dioxide and water. $\text{MgCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{MgCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$ To determine the rate of reaction, magnesium carbonate and dilute hydrochloric acid are mixed in a conical flask. The mass of the flask and its contents is recorded every twenty seconds. Which graph shows correctly how the mass of the flask and contents changes with time?
May/June 2017
A gas is produced during a reaction. Which two pieces of apparatus would allow the rate of this reaction to be measured?
May/June 2017
When the reaction begins, a $1.00\,\text{dm}^3$ solution contains $0.300\,\text{mol}$ of ethanol. By $100\,\text{s}$ the concentration of the ethanol has fallen to $0.296\,\text{mol dm}^{-3}$. What is the rate of reaction during the first $100\,\text{s}$?
May/June 2017
Which row shows the correct catalyst for the process named?
May/June 2017
In four different experiments, 1, 2, 3 and 4, nitric acid was added to excess marble chips and the amount of carbon dioxide produced was measured by volume. The same volume of nitric acid was used in every experiment. Either its concentration, or its temperature, or both its concentration and temperature, were altered. The outcomes of the experiments are shown on the graph. Which statement is correct?
May/June 2017
A student made two conclusions about calcium carbonate. Conclusion 1: The reaction with dilute hydrochloric acid happens more quickly with powdered calcium carbonate than with large pieces of calcium carbonate. Conclusion 2: Grinding large pieces of calcium carbonate into powder increases the surface area. Which statement is correct?
May/June 2018
The diagram below illustrates three stages in the production of sulfuric acid: sulfur $\xrightarrow{\text{step P}}$ sulfur dioxide $\xrightarrow{\text{step Q}}$ sulfur trioxide $\xrightarrow{\text{step R}}$ sulfuric acid. At which of these steps is a catalyst used?
May/June 2018
A student intends to demonstrate that the rate of the reaction between calcium carbonate and dilute hydrochloric acid doubles for each $10\,^{\circ}\text{C}$ increase in temperature. The student’s method is to measure the volume of carbon dioxide produced. The student has a Bunsen burner and a gas syringe. What other essential apparatus does the student need to use?
May/June 2018
Compound X reacts with an acid to form sulfur dioxide gas. A portion of X is put into a flask and acid is then added. The sulfur dioxide given off is collected, and its volume is recorded at different times. The outcomes are shown on a graph. Which statement about this experiment is correct?
May/June 2018
With a catalyst present, hydrogen peroxide, $\text{H}_2\text{O}_2$, breaks down into water and oxygen. A student compares the rate of this decomposition at two different temperatures.
May/June 2018
When calcium carbonate reacts with dilute hydrochloric acid, carbon dioxide gas is produced.
May/June 2018
A reaction rate experiment is carried out for calcium carbonate reacting with dilute hydrochloric acid. The gas produced is gathered in a gas syringe. Which other pieces of apparatus are needed to find how the reaction rate varies with temperature and the quantity of acid used?
May/June 2019
In three experiments, an equal mass of magnesium is allowed to react with the same volume of dilute sulfuric acid at room temperature. The magnesium is present in excess. experiment 1: Magnesium is used in large pieces. experiment 2: Magnesium is used in small pieces. experiment 3: Magnesium is used in large pieces, but the acid concentration is increased. Graphs showing the results are given. Which row is the correct one?
May/June 2019
An experiment is done to determine the rate of reaction between magnesium and dilute hydrochloric acid under two different conditions. In both experiments, the mass of magnesium and the number of moles of hydrochloric acid are identical. Graphs showing the results are displayed. Which statements might account for the difference between graph 1 and graph 2?
May/June 2019
Hydrogen peroxide breaks down slowly at room temperature. $2\text{H}_2\text{O}_2(aq) \rightarrow 2\text{H}_2\text{O}(l) + \text{O}_2(g)$ This reaction may be catalysed by adding manganese(IV) oxide. Which statement is correct when a catalyst is added to the aqueous hydrogen peroxide?
May/June 2019
Iron rusts in the presence of air and water, producing a solution that contains aqueous iron(III) ions. If an indicator is added to a solution containing aqueous iron(III) ions, it becomes dark blue. A student investigates how sodium chloride affects the rate at which iron rusts.
May/June 2019
Hydrogen peroxide, $\text{H}_2\text{O}_2$, reacts with iodide ions to make water and iodine, but the reaction only happens after acid has been added. $\text{H}_2\text{O}_2(aq) + 2\text{H}^+(aq) + 2\text{I}^-(aq) \rightarrow 2\text{H}_2\text{O}(l) + \text{I}_2(aq)$
May/June 2019
Which of these changes would increase the rate of a chemical reaction?
May/June 2021
When aqueous sodium thiosulfate is mixed with hydrochloric acid, the rate of reaction becomes faster if the concentration of each reactant is increased. Nitrogen gas reacts with hydrogen gas, and the reaction rate also increases if the pressure in the reaction vessel is raised. Which row gives the correct explanation for why the stated change makes the reaction happen faster?
May/June 2021
Sulfuric acid is made by the contact process. A number of substances take part in this process, among them vanadium(V) oxide and water. What roles do vanadium(V) oxide and water have in the contact process?
May/June 2021
Sulfamic acid, $\text{NH}_2\text{SO}_3\text{H}$, is a white crystalline solid. On reaction with aqueous sodium nitrite, nitrogen gas is produced, as represented by the equation: $\text{NH}_2\text{SO}_3\text{H}(s) + \text{NaNO}_2(aq) \rightarrow \text{N}_2(g) + \text{H}_2\text{O}(l) + \text{NaHSO}_4(aq)$.
May/June 2021
Aqueous iron(III) nitrate mixed with aqueous sodium thiosulfate gives a purple mixture. A reaction occurs in the mixture. Once the reaction is finished, the solution changes from purple to colourless.
May/June 2021
The apparatus illustrated is used to compare how quickly different metals react with hydrochloric acid.
May/June 2021
Sulfur dioxide combines with oxygen in the air. $2\text{SO}_2(\text{g}) + \text{O}_2(\text{g}) \rightleftharpoons 2\text{SO}_3(\text{g}) \quad \Delta H = -196\,\text{kJ mol}^{-1}$ In the absence of a catalyst, the reaction rate is very low. Which statement accounts for this?
May/June 2022
A student carries out an investigation into the rate of reaction between calcium carbonate and hydrochloric acid. The gas volume in the syringe is noted after 1 minute. The experiment is repeated using hydrochloric acid at different concentrations. Which further pieces of apparatus are needed for the investigation?
May/June 2022
Bromate, bromide and hydrogen ions react in the equation shown. $\text{BrO}_3^-(aq) + 5\text{Br}^-(aq) + 6\text{H}^+(aq) \rightarrow 3\text{Br}_2(aq) + 3\text{H}_2\text{O}(l)$. A piece of apparatus for finding out how the rate of this reaction changes with time is suggested. Which apparatus is suitable to measure the rate of this reaction?
May/June 2022
$25\,\text{cm}^3$ of $1.0\,\text{mol dm}^{-3}$ hydrochloric acid reacts with $10\,\text{g}$ of a solid to form a gas. The solid is in excess. The graph labelled first experiment shows how the volume of gas changes with time. Graphs P and Q show the volume of gas produced when the conditions are different. Which changes in conditions produce graphs P and Q, assuming that every other condition stays the same?
May/June 2022
Carbon monoxide and nitrogen monoxide are pollutant gases produced in a car engine.
May/June 2022
Carbon dioxide and sulfur dioxide are pollutants released at power stations that burn fossil fuels such as coal.
May/June 2022
The student pours $4.0\text{ cm}^3$ of aqueous potassium manganate(VII) from the burette into apparatus A.
May/June 2022
Using the apparatus shown, a student investigates how quickly excess copper(II) carbonate reacts with dilute sulfuric acid. $\text{CuCO}_3\text{(s)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{CuSO}_4\text{(aq)} + \text{CO}_2\text{(g)} + \text{H}_2\text{O\,(l)}$
May/June 2022
Two gases undergo reaction in a sealed vessel. Which change in conditions would make the reaction rate higher?
May/June 2023
Catalysts alter the rate of chemical reactions. Which statements correctly describe what happens when a catalyst is added to a reaction?
May/June 2023
Which method would be most effective for reducing the rate of the reaction between magnesium and sulfuric acid?
May/June 2023
The table shows two important industrial reactions involving gases. Which catalysts are stated correctly?
May/June 2023
A $2\ \text{g}$ portion of calcium carbonate reacts with dilute hydrochloric acid, as shown. $\text{CaCO}_3\text{(s)} + 2\text{HCl(aq)} \rightarrow \text{CaCl}_2\text{(aq)} + \text{CO}_2\text{(g)} + \text{H}_2\text{O(l)}$ Which alteration in conditions causes the reaction to take place more slowly?
May/June 2024
An excess of aluminium is allowed to react with dilute hydrochloric acid. $2\text{Al} + 6\text{HCl} \rightarrow 3\text{H}_2 + 2\text{AlCl}_3$ The hydrogen produced is gathered in a gas syringe. The overall volume of hydrogen in the gas syringe is measured at two-minute intervals. The outcomes of this experiment are shown. Which statement is correct?
May/June 2024
Two reactions each give a gaseous product. The reactions are carried out separately under the same temperature and pressure conditions. In each experiment, the volume of gas produced is recorded with time, and the outcomes are shown on the graph. At which point is the rate of gas production the greatest?
May/June 2024
A student is measuring how quickly a fixed mass of magnesium reacts with a fixed volume of dilute hydrochloric acid. Which other pieces of apparatus are needed for this experiment?
May/June 2024
When heated, aqueous ammonium nitrite breaks down to produce nitrogen. $\text{NH}_4\text{NO}_2(\text{aq}) \rightarrow \text{N}_2(\text{g}) + 2\text{H}_2\text{O}(\text{l})$
May/June 2024
When heated, aqueous hydrogen peroxide breaks down to make oxygen. $2\text{H}_2\text{O}_2(\text{aq}) \rightarrow \text{O}_2(\text{g}) + 2\text{H}_2\text{O}(\text{l})$
May/June 2024
The diagram illustrates apparatus set up to study two different reactions that give off gases. For each experiment, the reactants are combined and the mass of the flask plus its contents is measured every $30$ seconds. A graph of mass against time is plotted. In experiment $1$, solid X is calcium carbonate. In experiment $2$, solid X is magnesium. Which graph is the correct one?
May/June 2025
When aqueous sodium thiosulfate reacts with hydrochloric acid, the reaction rate rises if the concentration of each reactant is increased. When nitrogen gas reacts with hydrogen gas, the reaction rate rises if the pressure inside the reaction vessel is increased. Which row correctly states why the stated change makes the reaction rate increase?
May/June 2025
Magnesium is allowed to react with dilute sulfuric acid. $\text{Mg(s)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{MgSO}_4\text{(aq)} + \text{H}_2\text{(g)}$ The two experiments are both done at $25\,^{\circ}\text{C}$. experiment 1: $24.0\,\text{g}$ of powdered magnesium is reacted with $100\,\text{cm}^3$ of $1.0\,\text{mol dm}^{-3}$ sulfuric acid. experiment 2: $24.0\,\text{g}$ of powdered magnesium is reacted with $50\,\text{cm}^3$ of $2.0\,\text{mol dm}^{-3}$ sulfuric acid. For each experiment, the hydrogen volume is recorded at equal time intervals. These results are then shown on a graph. Which graph is correct?
May/June 2025
Which line shows the catalyst used for each of the two processes?
May/June 2025
Which change in conditions raises the energy of the particles in a reaction?
Oct/Nov 2015
Several reactions are given. Which of them use a catalyst when they are carried out industrially?
Oct/Nov 2015
A student places excess zinc into $50\,\text{cm}^3$ of $1.00\,\text{mol dm}^{-3}$ hydrochloric acid at $20\,^{\circ}\text{C}$. A graph, labelled G, is drawn to show how the volume of hydrogen gas produced changes with time. The experiment is carried out again under the same conditions, but this time the hydrochloric acid is at $40\,^{\circ}\text{C}$.
Oct/Nov 2015
A student carries out an investigation into how the concentration of a reagent influences the rate of a chemical reaction. Which piece of apparatus is needed for every rate investigation?
Oct/Nov 2016
Gold is used as a catalyst in some chemical reactions. In these reactions, gold: • lowers the energy cost of the reaction. • raises the yield of the reaction. • remains unchanged at the end of the reaction. • increases the speed of the reaction. How many of these statements are true?
Oct/Nov 2016
Which equation represents a reaction that takes place at room temperature and pressure?
Oct/Nov 2016
The statements below are about how catalysts are used in chemical reactions. Which statements are correct?
Oct/Nov 2016
In two experiments, 1 and 2, an excess of powdered calcium carbonate was added in a flask to dilute hydrochloric acid. For experiment 1, the carbon dioxide produced was collected, and the gas volume was recorded at regular intervals. For experiment 2, the mass of the flask and its contents was recorded at regular intervals. The outcomes from both experiments were then plotted on graphs. Which graphs correctly represent the results of these two experiments?
Oct/Nov 2016
When calcium carbonate is combined with dilute hydrochloric acid, carbon dioxide gas is given off. Three groups of apparatus are displayed. Which groups of apparatus are suitable, together with a stopwatch, for monitoring the rate of this reaction?
Oct/Nov 2016
In aqueous solution, peroxodisulfate ions, S$_2$O$_8^{2-}$, react with iodide ions. S$_2$O$_8^{2-}$(aq) + 2I$^-$(aq) $\rightarrow$ 2SO$_4^{2-}$(aq) + I$_2$(aq) The table displays how the relative rate of this reaction varies when different concentrations of peroxodisulfate ions and iodide ions are used.
Oct/Nov 2016
Propanone, CH$_3$COCH$_3$, reacts with iodine, I$_2$, to make colourless products. CH$_3$COCH$_3$ + I$_2$ $\rightarrow$ CH$_3$COCH$_2$I + HI Hydrochloric acid is the catalyst for this reaction. The table shows how the relative rate of reaction changes when different concentrations of propanone, iodine and hydrochloric acid are used.
Oct/Nov 2016
A student puts the catalyst manganese(IV) oxide into aqueous hydrogen peroxide, and the hydrogen peroxide breaks down: $\text{2H}_2\text{O}_2(aq) \rightarrow \text{2H}_2\text{O}(l) + \text{O}_2(g)$. The student then measures the volume of oxygen released at regular time intervals. This is experiment 1. The student carries out experiment 2 again, but with one altered condition. Graphs for experiments 1 and 2 are shown.
Oct/Nov 2016
A student puts excess zinc into hydrochloric acid and notes the volume of hydrogen gas released at regular time intervals. In experiment 2, the student alters one condition. The volume of hydrochloric acid is unchanged in both experiments.
Oct/Nov 2016
When conditions are appropriate, nitrogen reacts with oxygen to produce $\text{N}_2\text{O}$. $2\text{N}_2(g) + \text{O}_2(g) \rightleftharpoons 2\text{N}_2\text{O}(g)$ The energy profile diagram for this reaction is provided. Determine the activation energy for the reverse reaction.
Oct/Nov 2017
A chemist studied the rate of the reaction between ethene and hydrogen with a nickel catalyst. $\text{C}_2\text{H}_4(g) + \text{H}_2(g) \xrightarrow{\text{Ni}} \text{C}_2\text{H}_6(g)$ Three experiments were done by the chemist using different conditions. Which row is the correct one?
Oct/Nov 2017
Which row gives the right catalyst for each industrial process?
Oct/Nov 2017
A student tracks the rate of reaction between marble chips, $\text{CaCO}_3$, and dilute hydrochloric acid. $\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{CO}_2 + \text{H}_2\text{O}$ Which diagrams show apparatus that is appropriate for this experiment?
Oct/Nov 2017
Magnesium undergoes reaction with dilute sulfuric acid. $\text{Mg(s)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{MgSO}_4\text{(aq)} + \text{H}_2\text{(g)}$ There were two separate experiments. In experiment 1, $24.0\,\text{g}$ of magnesium was reacted with $100\,\text{cm}^3$ of $1.0\,\text{mol dm}^{-3}$ sulfuric acid. In experiment 2, $24.0\,\text{g}$ of magnesium was reacted with $50\,\text{cm}^3$ of $2.0\,\text{mol dm}^{-3}$ sulfuric acid. For each experiment, the hydrogen volume was recorded at different times. The data were then plotted on a graph. Which graph is the correct one?
Oct/Nov 2017
Which row gives the correct catalyst for each industrial process?
Oct/Nov 2017
A student monitors the rate of reaction between marble chips, $\text{CaCO}_{3}$, and dilute hydrochloric acid. $\text{CaCO}_{3} + 2\text{HCl} \rightarrow \text{CaCl}_{2} + \text{CO}_{2} + \text{H}_{2}\text{O}$ Which diagrams show apparatus that is appropriate for this experiment?
Oct/Nov 2017
When heated, nitrogen(V) oxide breaks down to make nitrogen(IV) oxide and oxygen. $2\text{N}_2\text{O}_5(g) \rightarrow 4\text{NO}_2(g) + \text{O}_2(g)$
Oct/Nov 2017
At room temperature, aqueous hydrogen peroxide breaks down in the presence of a catalyst to make water and oxygen. $2\text{H}_2\text{O}_2(\text{aq}) \rightarrow 2\text{H}_2\text{O}(\ell) + \text{O}_2(\text{g})$.
Oct/Nov 2017
A student examines how rapidly four metal carbonates break down. When metal carbonates are heated, they decompose and release a gas. The student proposes judging how readily different carbonates decompose by timing how long a sample of limewater takes to become milky, using the apparatus shown. The results of the investigation are shown in the table.
Oct/Nov 2017
The equation represents the reaction used to make ammonia. $\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$ Which change will lower the activation energy of this reaction?
Oct/Nov 2018
When calcium carbonate reacts with dilute hydrochloric acid, carbon dioxide is formed. The carbon dioxide is gathered with the apparatus shown. The reaction is carried out four times. In each reaction, $25\,\text{g}$ of calcium carbonate and an excess of hydrochloric acid are used. Which reaction mixture fills the gas syringe with carbon dioxide in the shortest time?
Oct/Nov 2018
This equation represents the reaction used in the production of ammonia. $\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g})$ Which change would lower the activation energy of the reaction?
Oct/Nov 2018
Cerium is a metal whose relative atomic mass is 140. Cerium powder undergoes reaction with sulfuric acid. $2\text{Ce}(s)+3\text{H}_2\text{SO}_4(aq)\rightarrow \text{Ce}_2(\text{SO}_4)_3(aq)+3\text{H}_2(g)$.
Oct/Nov 2018
When sulfuric acid reacts with zinc, zinc sulfate and hydrogen are produced. $\text{Zn(s)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{ZnSO}_4\text{(aq)} + \text{H}_2\text{(g)}$
Oct/Nov 2018
Mixing aqueous sodium thiosulfate, $\text{Na}_2\text{S}_2\text{O}_3$(aq), with dilute hydrochloric acid gives a pale yellow sulfur precipitate, so the reaction mixture turns cloudy. $\text{Na}_2\text{S}_2\text{O}_3$(aq) + 2HCl(aq) \rightarrow 2NaCl(aq) + S(s) + SO_2(g) + H_2O(l)$
Oct/Nov 2018
Calcium carbonate undergoes reaction with dilute hydrochloric acid. $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$ A student investigates the way the rate of this reaction changes when the temperature is increased.
Oct/Nov 2018
Gas P breaks down to produce gas Q. $x\text{P} \rightarrow y\text{Q}$ Two experiments are done to study the rate of reaction. All conditions are kept the same apart from the use of two different temperatures, $T_1$ and $T_2$. The outcomes are shown on graphs, each drawn using the same scale. Which row is correct?
Oct/Nov 2019
Catalysts can change how fast chemical reactions occur. Which statements correctly describe what happens when a catalyst is added to a reaction?
Oct/Nov 2019
This equation represents the reaction between calcium carbonate and hydrochloric acid. $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$
Oct/Nov 2019
Calcium carbonate reacts with dilute hydrochloric acid. $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$ A student examines how the rate of this reaction changes at three different temperatures using the apparatus shown. In each trial, the student adds dilute hydrochloric acid to an excess of calcium carbonate. The volume of carbon dioxide in B is measured every 30 seconds.
Oct/Nov 2019
Calcium carbonate reacts with dilute hydrochloric acid. $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$ Vigorous bubbling is observed. A student studies the rate of this reaction with three calcium carbonate samples, each having a different particle size. For every experiment the student adds all of the calcium carbonate, in excess, to dilute hydrochloric acid in apparatus E. The weighing bottle is put back on the balance. The mass is noted every 30 seconds. In experiment 1 the student uses large lumps of calcium carbonate.
Oct/Nov 2019
When calcium carbonate is mixed with dilute hydrochloric acid, carbon dioxide gas is given off. Three arrangements of apparatus are shown. Which of the apparatus arrangements are appropriate, along with a stop-watch, for monitoring the rate of this reaction?
Oct/Nov 2020
An energy profile diagram showing both the catalysed and uncatalysed reactions between $\text{N}_2$ and $\text{H}_2$ in the Haber process is displayed. What is the activation energy for forming $\text{NH}_3$ when a catalyst is present?
Oct/Nov 2020
When calcium carbonate is introduced to dilute hydrochloric acid, carbon dioxide gas is given off. Three apparatus arrangements are shown. Which arrangements of apparatus are suitable, together with a stop-watch, for monitoring the rate of this reaction?
Oct/Nov 2020
The energy profile diagram for a chemical reaction is shown. What is the activation energy of the reaction?
Oct/Nov 2020
On heating, metal carbonates break down and release a gas that makes limewater go milky. A student studies how quickly four metal carbonates decompose using the apparatus shown. The student: - heats each metal carbonate separately with a Bunsen burner - records the time taken for the limewater to become milky. The results are displayed in the table.
Oct/Nov 2020
On heating, solid Group I nitrates break down and release a gas that will relight a glowing splint. A student investigates how quickly four Group I nitrates decompose. Each nitrate is heated separately with a Bunsen burner, and the student times how long it takes for a glowing splint to relight for each one.
Oct/Nov 2020
The equation below represents the reaction used to produce ammonia. $\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g})$ Which change would reduce the activation energy for this reaction?
Oct/Nov 2021
A student monitors the rate of reaction between marble chips, $\text{CaCO}_3$, and dilute hydrochloric acid. $\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{CO}_2 + \text{H}_2\text{O}$ Which diagrams show the apparatus that is suitable for this experiment when used with a stopwatch?
Oct/Nov 2021
The equation represents the reaction used to make ammonia. $\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$. Which change will reduce the activation energy of the reaction?
Oct/Nov 2021
The apparatus is used to monitor the rate of reaction between magnesium carbonate, $\text{MgCO}_3$, and dilute nitric acid, $\text{HNO}_3$. $\text{MgCO}_3(s) + 2\text{HNO}_3(aq) \rightarrow \text{Mg(NO}_3)_2(aq) + \text{H}_2\text{O}(l) + \text{CO}_2(g)$ The graph plots the volume of gas collected against time. Three claims are given about the experiment. 1. The mass of the flask and its contents falls as time passes. 2. The reaction rate falls as time passes. 3. The reaction has ended after four minutes. Which statements are correct?
Oct/Nov 2021