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Energetics

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Question 23

A student investigates the reaction between dilute hydrochloric acid and aqueous potassium hydroxide in a polystyrene cup. He records the following data:

  • Volume of dilute hydrochloric acid = 35.0 cm3
  • Volume of aqueous potassium hydroxide = 35.0 cm3
  • Initial temperature of both solutions = 18.5∘C18.5^\circ\text{C}18.5∘C
  • Final maximum temperature of the mixture = 24.7∘C24.7^\circ\text{C}24.7∘C
a.

Explain why a polystyrene cup is preferred over a glass beaker for this experiment.

[2]
b.

Calculate the heat energy change during this reaction, in joules (J\text{J}J), using the equation:

heat energy change=mass×4.2×temperature change \text{heat energy change} = \text{mass} \times 4.2 \times \text{temperature change} heat energy change=mass×4.2×temperature change

Assume that 1.0 cm3 of each solution has a mass of 1.0 g.

[4]
Markscheme

Energetics Questions

  1. IGCSE
  2. /Chemistry
  3. /Energetics

35 exam-style questions on Edexcel IGCSE Chemistry Energetics. Each one has a worked solution and a mark scheme showing where the marks go.

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