chem vocab

Enthalpy of a reaction

Delta H is the energy difference from the reactants to the products.

Activation energy (Ea)

The energy difference from the reactants to the transition state.

Reaction rate

The rate at which the reactants of a chemical reaction form the products.

Collision theory

For a collision to be effective, reactant particles must possess sufficient kinetic energy to break the necessary bonds in the reactants.

Activation energy

The minimum energy requirement for colliding particles to react.

Activated complex

The transition state that exists for a short period in a chemical reaction as the bonds in the reactants are breaking and the bonds in the products are forming.

Reaction intermediate

A product of one step in a multistep reaction that acts as a reactant in a following step.

Catalyst

A substance that increases reaction rates by providing a lower energy path for the reaction without being used up during the reaction.

Enzymes

Proteins or other molecules that fold into specific shapes to form active sites.

Reversible reactions

Product molecules under ordinary conditions can react to form the original reactant molecules.

Chemical equilibrium

A state of balance where the rates of the forward and reverse reactions are equal.

Equilibrium position

The relative concentrations of the reactants and products at equilibrium.

Le Chatelier’s principle

If a chemical system at equilibrium experiences a disturbance, it changes in a way that counteracts the change as it returns to equilibrium.

Crossover temperature

The outdoor air temperature where the system transitions from using the heat pump for heating to utilizing a backup heating source.

Equilibrium constant

The value of the reaction quotient at chemical equilibrium.

Equilibrium position

A state where a system is at rest and the net force acting on it is zero.