Endothermic and Exothermic Processes
Explore the fundamental concepts of endothermic and exothermic reactions, including energy changes,enthalpy, and real-world examples at a Grade 12 Chemistry level.
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Endothermic and Exothermic Processes
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Read each question carefully and provide concise, accurate answers. Show all work for calculations.
1. Which of the following statements is true for an exothermic reaction?
The enthalpy change (ΔH) is positive.
Heat is absorbed from the surroundings.
The products have lower energy than the reactants.
The reaction vessel feels cold to the touch.
2. An ice pack used for injuries feels cold. This is an example of a/an:
Exothermic process
Endothermic process
Isothermal process
Adiabatic process
1. Combustion reactions are typically endothermic.
True
False
2. In an endothermic process, the system releases heat to the surroundings.
True
False
1. The breaking of chemical bonds typically requires energy input, making it an process.
2. When ΔH is negative, the reaction is , releasing heat into the surroundings.
3. Photosynthesis is an example of an process because it absorbs light energy from the sun.
1. Explain the difference between an endothermic and an exothermic reaction in terms of energy flow and enthalpy change (ΔH).
2. Provide two real-world examples for both endothermic and exothermic processes, and briefly explain why they fit that classification.
Consider the following energy diagram for a hypothetical reaction:
1. Is the reaction depicted in the diagram endothermic or exothermic? Justify your answer.
2. Based on the diagram, would you expect the ΔH value to be positive or negative?