Reactivity 1.2—Energy cycles in reactions HL Flashcards
Combustion
An exothermic chemical process
where a substance is combined with oxygen gas
Molar enthalpy of combustion
The enthalpy change when one mole of a substance is burned completely in oxygen under standard conditions. Known as the standard enthalpy of combustion.
Molar enthalpy of formation
The energy change that occurs when one mole of a substance is formed from its constituent elements in their standard state. Known as the standard enthalpy of formation.
Diatomic Elements
They are called diatomic elements because the atoms appear in pairs. The chemical formulas for these elements are H2, N2, O2, F2, Cl2, Br2, and I2.
Enthalpy of atomisation
The enthalpy change when one mole of gaseous atoms is formed from an element in its standard state.
Ionisation energy
The energy required with remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions.
Bond energy, E
The energy required to break one mole of
bonds in the gaseous state.
Electron affinity
The amount of energy released when a neutral atom gains an electron to form a negatively charged ion.
Lattice enthalpy
The enthalpy change when one mole of a solid ionic compound breaks down to form individual gaseous ions.
Born-Haber cycle
An energy cycle that can be used to calculate the lattice enthalpy of an ionic compound.
Which compound is expected to demonstrate stronger alignment between the experimental (Born-Haber) and theoretical lattice enthalpy values: NaBr or BeCl?
NaBr exhibits greater ionic character in comparison to BeCl, thus leading to a more favorable alignment between the experimental and theoretical lattice enthalpies.
