Endothermic and exothermic

endothermic and exothermic reactions are

changes in heat

endothermic

heat moves from the surroundings into the system

exothermic

heat moves out of a system into the surroundings

endothermic

absorb heat energy

exothermic

release heat energy

endothermic

negative ΔH

exothermic

positive ΔH

H

Enthalpy

What is enthalpy?

The amount of heat energy in a system

ΔH

Σbonds broken - Σbonds formed

Q

Heat

Endothermic

energy in products are smaller than the energy in reactants

Exothermic

energy in products are larger than the energy in the reactants

Endothermic

ice melting

Exothermic

Gas condensing

Endothermic

bonds break

Exothermic

Bonds form

Endothermic

Exothermic

Activation energy

energy needed for a chemical reaction to occur

Bond enthalpy

energy required to break covalent bonds in a gaseous molecule