Energetics Flashcards
What are the standard conditions enthalpy is usually measured under?
100kpa
298K
Solutions at 1mol/dm3
All substances at normal state
Define enthalpy change of reaction
The enthalpy change when quantities of substances in standard states react completely under standard conditions
Define enthalpy change of formation
The standard enthalpy change of formation of a compound is the enthalpy change when 1 mole of the compound is formed from its elements under standard conditions (298K and 100kpa), all reactants and products being in their standard states
Define enthalpy change of combustion
The standard enthalpy of combustion of a substance is defined as the enthalpy change that occurs when one mole of a substance is combusted completely in oxygen under standard conditions. (298K and 100kPa), all reactants and products being in their standard states
Define enthalpy change of neutralisation
The standard enthalpy change of neutralisation is the enthalpy change when solutions of an acid and an alkali react together under standard conditions to produce 1 mole of water.
Finish the sentence: The meausred change in temperature is propotional to…
the energy change
Define specific heat capacity
The energy required to raise 1g of substance by 1K w/o a change of state
Define enthalpy change
The amount of heat energy taken in or given out during any change in a system provided the pressure os constant
Draw a exothermic change energy graph
Draw an endothermic change energy graph
Draw the symbol used when enthalpy change is measured at standard conditions
States Hess’s law
Totla enthalpy change for a reaction is independent of the route by which the chemical change takes place
Define bond enthalpy
The enthalpy needed to break the covalent bond into gaseous atoms average over different molecules
