Thermochemistry Flashcards

Flashcards based on thermochemistry lecture notes.

Exothermic Reactions

Chemical reactions that release heat to the surroundings, causing the surrounding temperature to rise and the container to become hot.

Endothermic Reactions

Chemical reactions that absorb heat from the surroundings, causing the temperature to drop and the container to become cold.

Examples of Exothermic Reactions

Examples include respiration, oxidation of metals, neutralization reaction, combustion of fuel, production of ammonia, and dissolving sodium hydroxide in water.

Examples of Endothermic Reactions

Examples include photosynthesis, decomposition of metal carbonate when heated, decomposition of metal nitrates when heated, and dissolving ammonium salts in water.

Heat of Reaction (ΔH)

The heat absorbed or released during a chemical reaction; unit is kJ mol−1.

Exothermic Reaction ΔH

ΔH is given a negative sign.

Endothermic Reaction ΔH

ΔH is given a positive sign.

Heat of Reaction, ΔH

Heat change of one mole of reactant that reacts or one mole of product that is formed.

Heat of Precipitation

The heat change when 1 mole of precipitate is formed from their ions in an aqueous solution.

Heat of Displacement

The heat change when one mole of a metal is displaced from its salt solution by a more electropositive metal.

Heat of Neutralisation

The heat change when one mole of water is formed from the reaction between an acid and an alkali.

Heat of Combustion

The heat released when 1 mole of a substance is completely burnt in excess oxygen, O2.

Fuel Value

The amount of heat energy released when one gram of fuel is completely burnt in excess oxygen.

Heat Capacity

The quantity of heat energy required to raise the temperature of an object by 1 degree Celsius (°C) or 1 Kelvin (K).

The amount of heat required to raise the temperature