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Questions and Answers
What characterizes an exothermic reaction in terms of energy transfer?
What characterizes an exothermic reaction in terms of energy transfer?
Which statement correctly defines activation energy?
Which statement correctly defines activation energy?
In an endothermic reaction, the surroundings typically experience which of the following changes?
In an endothermic reaction, the surroundings typically experience which of the following changes?
Which of these best describes a chemical cell?
Which of these best describes a chemical cell?
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Which factor does NOT affect the temperature change in reacting solutions?
Which factor does NOT affect the temperature change in reacting solutions?
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What occurs during the breaking of bonds in terms of energy?
What occurs during the breaking of bonds in terms of energy?
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Which is true about alkaline batteries?
Which is true about alkaline batteries?
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In a reaction profile for an exothermic reaction, which of the following is true?
In a reaction profile for an exothermic reaction, which of the following is true?
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Study Notes
Exothermic and Endothermic Reactions
- Exothermic reactions: release energy to the surroundings, causing the temperature of the surroundings to increase. Examples include combustion, burning fuels and hand warmers.
- Endothermic reactions: absorb energy from the surroundings, causing the temperature of the surroundings to decrease. Examples include melting ice, photosynthesis and dissolving ammonium nitrate in water.
- Collision Theory: states that chemical reactions only occur when reacting particles collide with sufficient energy to overcome the activation energy.
- Activation energy: the minimum amount of energy that reacting particles need to have in order to react.
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Reaction profiles: show the energy changes that occur during a reaction.
- Exothermic reaction: Products have lower energy than reactants, resulting in a negative overall energy change.
- Endothermic reaction: Products have higher energy than reactants, resulting in a positive overall energy change.
- Bond breaking: requires energy, endothermic process.
- Bond forming: releases energy, exothermic process.
- Overall energy change: the difference between the energy required to break bonds and the energy released when bonds are formed.
Chemical Cells and Fuel Cells
- Simple cell: a device that converts chemical energy into electrical energy. It consists of two electrodes (made of different metals) in an electrolyte.
- Battery: a collection of simple cells connected together to provide a greater voltage.
- Alkaline batteries: are non-rechargeable because the chemical changes that occur during the reaction are irreversible.
- Rechargeable batteries: use reversible reactions, allowing them to be recharged by applying electrical energy to reverse the chemical changes.
- Fuel cells: generate electricity directly from a fuel, typically hydrogen. The reaction between hydrogen and oxygen produces water and electricity, with no harmful emissions.
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Description
Test your understanding of exothermic and endothermic reactions through this quiz. Explore key concepts like energy changes, activation energy, and collision theory. Ideal for students studying chemistry and reaction dynamics.
