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Question 1
This question is about reaction profiles and enthalpy. The diagram below shows a typical reaction profile for the decomposition of hydrogen peroxide. |
a) | Which letter represents the activation energy? A B C D
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b) | The decomposition of hydrogen peroxide results in energy being given to the surroundings. What type of reaction is this? A displacement B endothermic C exothermic D neutralisation
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c) | What does arrow C represent? A change in temperature B overall energy change C activation energy D energy of hydrogen peroxide
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Question 2
Butane (C4H10) reacts with oxygen in the air when combusted to form carbon dioxide and water. |
a) | Complete the balanced chemical equation to show the combustion of butane.
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b) | Draw the structure of butane C4H10 to show all the covalent bonds.
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c) | The table below shows the bond energies for the bonds. Calculate the energy to break all the bonds in the reactants.
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d) | Calculate the energy released when all the bonds in the products are formed.
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e) | Calculate the molar enthalpy change (ΔH) in kJ/mol, for the combustion of butane. Include a sign in your answer.
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Question 3
A student is investigating the temperature change during a chemical reaction. This is the method the student used:
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a) | The table below shows how the temperature varied during the reaction. Model answer
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b) | The student repeats the experiment with 5 cm3 of dilute hydrochloric acid. Draw how the temperature would vary with time.
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c) | The temperature increased during the reaction. State whether the reaction is endothermic or exothermic.
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d) | Sketch the reaction profile for the reaction between hydrochloric acid and sodium hydroxide. Your diagram should include:
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Question 4
A student is investigating the energy change when a piece of magnesium ribbon is dropped into hydrochloric acid. |
a) | Write a balanced chemical equation for the reaction between magnesium and hydrochloric acid (HCl) to form magnesium chloride and hydrogen.
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b) | The reaction results in energy being transferred to the surroundings. Draw a reaction profile for the reaction between magnesium and hydrochloric acid.
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Question 5
This question is about the reaction between methane and steam to produce hydrogen. |
a) | Write a balanced symbol equation for the reaction between methane and steam. Include state symbols.
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b) | The table below shows the bond energies for the reaction between methane and steam. Calculate the energy change for the forward reaction.
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c) | Complete the reaction profile for the reaction between methane and steam to form hydrogen and carbon monoxide.
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d) | The reaction is reversible. State the effect of increasing the temperature on the yield of hydrogen.
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Question 6
This question is about the combustion of propane. |
a) | State what is meant by the term activation energy.
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b) | Sketch the structure of propane to show all the covalent bonds.
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c) | Write a balanced symbol equation for the combustion of propane.
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d) | The table below shows the bond energies for the reaction. Calculate the energy change for the reaction and state whether the reaction is endothermic or exothermic.
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Question 7
A student is investigating the reactivity of group 1 metals. The student's method is below:
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a) | State the name of the piece of equipment used to measure temperature.
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b) | Suggest two variables the student would need to control during this investigation.
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c) | The table below shows the student's results. Calculate the temperature rise for the reaction between potassium and water.
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d) | Describe the pattern shown by the student's results and explain how this shows the trend in reactivity as you go down group 1.
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e) | The student draws a reaction profile for the reaction between group 1 metals and water. The reaction profile is incorrect. State two errors in the reaction profile.
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