Chemistry Chapter 8 - (Energy Changes)

Define the term “Exothermic Reaction”.

A chemical reaction that releases thermal energy into the surroundings.

Physical process of exothermic.

Condensation.

Freezing.

Dissolving of anhydrous salt in water.

Dissolving of acids and alkalis in water.

Chemical reaction of exothermic.

Combustion of fuels.

Respiration.

Corrosion of metals (reaction with oxygen).

Neutralisation.

Energy level for exothermic.

Reactants are higher than the products.

ΔH is negative.

Define the term “Endothermic Reaction”.

A chemical reaction that absorbs thermal energy from the surroundings.

Physical process of endothermic.

Evaporation/Boiling.

Melting.

Dissolving some ionic compounds in water (e.g ammonium chloride).

Dissolving crystalline salts in water (e.g copper (II) sulfate crystals).

Chemical reaction for endothermic.

Photosynthesis.

Thermal decomposition.

Reaction of sodium hydrogen carbonate with dilute acids.

Energy level for endothermic.

Reactants are lower than products.

ΔH is positive.

Reaction pathway diagram for an “Exothermic Reaction”.

Reaction pathway diagram for an “Endothermic Reaction”.

Define the term “Enthalpy Change (ΔH)”.

Difference in energy content of the reactants and products.

Define the term “Activation Energy”.

The minimum energy needed by colliding particles to react.