Starter quiz
- Match the following state symbols to the correct meaning.
- (aq)⇔aqueous ✓
- (s)⇔solid ✓
- (l)⇔liquid ✓
- (g)⇔gas ✓
- Which of the following statements about exothermic reactions are true?
- They cause an increase in temperature. ✓
- They transfer energy from the surroundings to the products.
- They cause a decrease in temperature.
- They transfer energy from the reactants to the surroundings. ✓
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- What is the SI unit for energy?
- 'joule' ✓
- Which statement about energy is correct?
- It can be created and destroyed.
- It can be created, but not destroyed.
- It can be destroyed, but not created.
- It cannot be created or destroyed. ✓
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- The hotter an object, the more energy is present in its ______ store of energy.
- thermal ✓
- elastic potential
- kinetic
- magnetic
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- Which of the following methods of energy transfer involves only the vibration of particles?
- thermal radiation
- thermal conduction ✓
- thermal convection
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Exit quiz
- Match the following terms to the correct definition.
- Exothermic⇔Chemical reaction in which energy is transferred to the surroundings. ✓
- Endothermic⇔Chemical reaction in which energy is transferred to the products. ✓
- Solution⇔Formed when a substance dissolves in a liquid. ✓
- Calorimetry⇔An experiment used to measure energy change during a reaction. ✓
- Which of the following are examples of exothermic chemical reactions?
- Most neutralisation reactions ✓
- Respiration ✓
- Thermal decomposition
- All precipitation reactions
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- After an endothermic reaction, the temperature of the surroundings ______.
- Increases
- Decreases ✓
- Stays the same
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- Which of the following are examples of everyday uses of exothermic reactions?
- Self-cooling drinks
- Self-heating drinks ✓
- Sports injury cool packs
- Hand warmers ✓
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- Barium sulphate, BaSO₄, is a precipitate produced during a chemical reaction. Which state symbols should appear after BaSO₄ in the symbol equation?
- '(s)' ✓
- A student measured the initial temperature of a reaction as 22°C and the final temperature as 16°C. Which of these statements about the reaction are true?
- The difference in temperature is -6°C. ✓
- The reaction is endothermic. ✓
- The reaction is exothermic.
- The reaction could be combustion.
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Worksheet
Presentation
Video
Lesson Details
Key learning points
- Changes in heat energy accompany salts dissolving in water.
- Changes in heat energy accompany neutralisation, displacement and precipitation reactions.
- Exothermic and endothermic reactions have everyday uses.
- When reactions take place in solution, temperature changes can be measured to reflect the energy changes.
Common misconception
Pupils struggle to identify the surroundings in exothermic and endothermic reactions and why the temperature decreases in endothermic reactions when energy is transferred into the reaction.
Explain that the surroundings are where you are making the temperature measurements and that the energy is transferred from the thermal energy store of the surroundings to the chemical energy store of the reaction.
Keywords
Exothermic - An exothermic chemical reaction is a type of reaction in which energy is transferred from the reactants to the surroundings e.g. combustion.
Endothermic - An endothermic chemical reaction is a type of reaction in which energy is transferred from the surroundings to the products e.g. photosynthesis.
Solution - A solution is formed when a substance dissolves into a liquid.
Calorimetry - Calorimetry is an experiment than can be used to measure an energy change during a reaction.