5- Energetics

Question 1

Exothermic reaction

Answer 1

A reaction that releases heat to the surroundings.

Question 2

Endothermic reaction

Answer 2

A reaction that absorbs heat from the surroundings.

Question 3

Enthalpy

Answer 3

Heat energy converted from energy contained in chemical bonds.

Question 4

Standard Enthalpy Change of Reaction

Answer 4

the enthalpy change when molar quantities of reactants in their normal states react to form products in their normal states under standard conditions of temperature (298 K) and pressure (101.3 kPa or

Question 5

Standard state

Answer 5

Under the conditions of: (1) temperature of a substance at exactly 25°C; (2) pressure of gaseous substance are exactly 1 atm; (3) liquids and solids are pure; (4) aqueous solutions are exactly 1 mol×d

Question 6

Average Bond Enthalpy

Answer 6

The energy change that occurs when 1 mol of a covalent bond in the gaseous state is formed from its gaseous atoms.

Question 7

Standard Enthalpy Change Of Formation

Answer 7

The change in enthalpy that accompanies the formation of one mole of a compound from its elements with all substances in standard states.

Question 8

Standard Enthalpy Change of Combustion

Answer 8

The change in enthalpy that accompanies the formation of one mole of a compound from its complete reaction with oxygen gas under standard conditions.

Question 9

Lattice Enthalpy

Answer 9

The enthalpy change that results when a solid ionic salt is formed from its gaseous ions under standard conditions.

Question 10

Electron Affinity

Answer 10

The enthalpy change associated with the addition of an electron to a gaseous atom.