5.1.4

Required Practical: Temperature Changes

Test yourself

Investigating Temperature Changes in Chemical Reactions

The aim of this experiment is to explore how different variables influence the change in temperature when substances react in solution.

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Apparatus

  • Polystyrene cup (for insulation)
  • 250 cm3 beaker (to support the cup)
  • Thermometer
  • Measuring cylinder
  • Top-pan balance
  • Stopwatch (if required for timing reactions)
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Planning

  • You can examine different temperature changes by choosing suitable reaction types, such as:
    • acid + metals
    • acid + carbonates
    • acid + alkali (neutralisation)
    • displacement of metals
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Variables

  • Independent variable:
    • Concentration of acid, or type of metal, or surface area of solid
  • Dependent variable:
    • The temperature change (increase or decrease)
  • Control variables:
    • Volume of reactants, initial temperature, and duration of measurement
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Method: Solution + Solution

  • Place a polystyrene cup inside a beaker to prevent it from tipping.
  • Measure a fixed volume of the first solution and pour it into the cup.
  • Record its starting temperature.
  • Measure an equal volume of the second solution and add it quickly to the cup.
  • Stir and note the maximum or minimum temperature reached.
  • Repeat the procedure for different values of your independent variable (e.g. acid concentration or type of acid).
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Method: Solid + Solution

  • Place a polystyrene cup inside a beaker for safety.
  • Measure and pour a fixed volume of acid into the cup.
  • Record the starting temperature of the solution.
  • Measure the mass of the metal.
  • Add the solid to the acid and gently swirl the mixture.
  • Record the highest or lowest temperature reached.
  • Repeat using different variables such as the type of metal, surface area, or acid concentration.
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Analysis

  • A larger temperature change indicates that more energy has been transferred.
    • Exothermic reactions release heat into the surroundings, causing a temperature rise.
    • Endothermic reactions absorb energy, resulting in a temperature drop.
  • Plot the data on a graph of temperature change (°C) against the chosen independent variable to observe trends.
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Hazards and precautions

  • Dilute acids or alkalis:
    • These may irritate the skin or eyes
    • Wear goggles and handle with care
  • Metal salt solutions:
    • Some may be harmful to the environment
    • Dispose of waste properly; do not pour it into sinks
  • Exothermic reactions:
    • Heat can be released suddenly
    • Avoid holding the reaction vessel; use a beaker for support

Jump to other topics

1Atomic Structure

2Chemical Bonding

3Quantitative Chemistry

4Chemical Changes

5Energy Changes

6The Rate & Extent of Chemical Change

7Organic Chemistry

8Chemical Analysis

9Chemistry of the Atmosphere

10Using Resources

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