Energy Change & Rates Of Reactions Flashcards
Heat of Reaction (🔺H)
The net change of chemical potential of the system.
Exothermic Reactions
Reactions which transform chemical potential energy into thermal energy (🔺H < 0).
Endothermic Reaction
Reactions which transform thermal energy into chemical potential energy (🔺H > 0).
What do exothermic reactions do in relation to temperature and heat?
Exothermic reactions release heat and thus increase the temperature of the surroundings.
What do endothermic reactions do in relation to temperature and heat?
Endothermic reactions absorb heat and thus decrease the temperature of the surroundings.
Activation Energy
The minimum energy required to start a chemical reaction.
OR
The energy required to form the activated complex.
Activated Complex
A high energy, unstable, temporary transition state between the reactants and the products.
Reaction Rate
The change in amount or concentration per unit time of either a reactant or product.
Catalyst
A substance that increases the rate of the reaction but remains unchanged at the end of the reaction.
What are the two conditions for reactant particles to collide effectively (collision theory)?
An effective (or successful) collision is one in which the colliding reactant particles have:
What happens to energy when a bond breaks?
Bond breaking absorbs energy.
What happens to energy when a bond is formed?
Bond formation releases energy.
What type of bond requires more energy to break?
A stronger bond requires more energy to break.
What type of bond requires less energy to break?
A weaker bond requires less energy to break.
Does a stronger bond release more or less energy than a weaker bond when formed?
A stronger bond releases more energy when formed.
