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Exothermic and endothermic reactions key terms
Study Exothermic and endothermic reactions with curriculum-aligned Key Terms resources, practice links, and exam-focused support.
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key terms
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Exothermic and endothermic reactions
Key terms
Collision theory
The theory that chemical reactions occur only when reacting particles collide with sufficient energy.
Activation energy
The minimum energy that reacting particles must possess for a chemical reaction to occur.
Collision theory
The theory that chemical reactions occur only when reacting particles collide with sufficient energy.
Activation energy
The minimum energy that reacting particles must possess for a reaction to occur. In Reaction profiles, this term is used specifically to support the learning objective: explain that reacting particles must collide with sufficient energy for a reaction to occur.
Activation energy
The minimum energy particles need to react. In Reaction profiles, this term is used specifically to support the learning objective: define activation energy as the minimum energy particles need to react.
Reaction profile
A graphical representation showing the energy changes during a chemical reaction. In Reaction profiles, this term is used specifically to support the learning objective: define activation energy as the minimum energy particles need to react.
Exothermic Reaction
A reaction that transfers energy to the surroundings, resulting in an increase in the temperature of the surroundings.
Reaction Profile
A graphical representation showing the energy changes during a chemical reaction, indicating the energy of reactants and products.
Reaction profile
A graph showing the change in energy of a reaction system as the reaction proceeds, with reactants, products, activation energy, and overall energy change marked.
Endothermic reaction
A reaction that absorbs energy from the surroundings, resulting in a higher energy state for the products than for the reactants.
Reactants
The substances present at the start of a chemical reaction, shown at the left side of a reaction profile.
Products
The substances formed after a chemical reaction, shown at the right side of a reaction profile.
Activation energy
The minimum energy particles need to react. In Reaction profiles, this term is used specifically to support the learning objective: label activation energy on a reaction profile.
Reaction profile
A graphical representation showing the energy changes during a chemical reaction. In Reaction profiles, this term is used specifically to support the learning objective: label activation energy on a reaction profile.
overall energy change
The difference in energy between the reactants and products in a chemical reaction, indicating whether energy is absorbed or released.
reaction profile
A graphical representation showing the energy changes during a chemical reaction, including the energy of reactants, products, and activation energy.
Exothermic reaction
A reaction that transfers energy to the surroundings, resulting in an increase in the temperature of the surroundings.
Endothermic reaction
A reaction that takes in energy from the surroundings, resulting in a decrease in the temperature of the surroundings.
Reaction profile
A graph showing the energy of reacting particles over time, with a curved line indicating how energy rises to a peak (activation energy) and then falls as products form.
Curved line
The continuous part of a reaction profile that represents the gradual change in energy of the system as the reaction proceeds from reactants to products.
Exothermic reaction
A reaction that transfers energy to the surroundings, resulting in an increase in the temperature of the surroundings.
Endothermic reaction
A reaction that takes in energy from the surroundings, resulting in a decrease in the temperature of the surroundings.
Bond breaking
The process of supplying energy to overcome the forces holding atoms together in a molecule.
Exothermic reaction
A chemical reaction that releases energy to the surroundings, resulting in an increase in temperature.
Bond formation
The process in which energy is released when chemical bonds are created between atoms in products.
Exothermic reaction
A chemical reaction that releases energy to the surroundings, resulting in an increase in temperature.
Bond energy
The amount of energy required to break one mole of a specific bond in a molecule. In The energy change of reactions (HT only), this term is used specifically to support the learning objective: (HT only) Explain that bond energies can be used to calculate energy needed to break bonds.
Exothermic reaction
A reaction that transfers energy to the surroundings, resulting in an increase in temperature.
Bond energy
The energy required to break one mole of a bond in a substance. In The energy change of reactions (HT only), this term is used specifically to support the learning objective: (HT only) Explain that bond energies can be used to calculate energy released when bonds form.
Energy released
The energy that is given off when bonds are formed in a chemical reaction. In The energy change of reactions (HT only), this term is used specifically to support the learning objective: (HT only) Explain that bond energies can be used to calculate energy released when bonds form.
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