Questions
Q1 What is an exothermic reaction?
Q2 When an endothermic reaction takes place, the temperature around the reaction decreases. Explain why.
Q3 Sketch a reaction profile for an exothermic reaction and add the following labels to it.
a) The energy of the reactants.
b) The energy of the products.
c) The overall energy change.
Complete
Q4 ƒ Dissolving ammonium chloride … the temperature of the reaction mixture — it’s endothermic.
Q5ƒ Dissolving calcium chloride causes the temperature of the solution to …— it’s exothermic.
Q6ƒ Most neutralisation reactions are ….:
e.g. HCl + NaOH ⇾ NaCl + H₂O
Q7ƒ However, the neutralisation reaction between ethanoic acid and sodium carbonate is …..
Q8 ƒIn a displacement reaction
a more reactive element displaces a less reactive element in a compound. These types of reactions are accompanied by a … of energy — they’re exothermic.
Q9ƒ Zinc powder and copper sulfate react in a displacement reaction forming zinc ….and copper.
Q9ƒPrecipitation reactions Precipitates are insoluble solids which can sometimes form when two solutions are mixed together. All precipitation reactions are ….
Q10ƒ The reaction between lead(II) nitrate solution and potassium iodide forming a lead iodide precipitate would result in an increase in the temperature of the surroundings.
Q11ƒ A student wants to measure the temperature change when a solution of potassium hydroxide reacts with sulfuric acid.
a) Describe a method the student could use to measure the temperature change of this reaction.
b) The reaction between potassium hydroxide and sulfuric acid is exothermic. Describe the temperature change the student will observe.
