Flashcards
unit 5 thermodynamics
Cards in this deck (15)
- 1Error in calorimeter experiment of combustion of ethanolnot all heat produced was transferred to the water.
water loses some heat to the surroundings.
incomplete combustion of ethanol - 2Definie Hess's lawthe enthalpy change occurs, for any reaction independent of the route, provided the initial and final conditions.
- 3Defnie Standar enthalpy of formationthe enthalpy change that occurs, when one mole of substance is formed from its element in standard conditions.
product-reactant - 4describe the endothermic processbreaking bonds, atoms are separated, which are attracted by electrostatic forces. Thus, needing energy.
Reactants more stable than product. But enthalpy of the product is stronger.
T decreases. - 5describe the exothermic processbonds forming, so atoms are bonded together, which are attracted by electrostatic forces. Thus, releasing energy.
T decreases
products more stable than reactants. ENthaply of reactants greater. - 6standard enthaply of combustionis the enthalpy change that occurs, when one mole of a substance is combusted in oxygen under standard conditions.
reactants - products. - 7Emergy cycles Born haber cycle. atom and I.Eatomization: is the enthalpy change that occurs when one mole of a gaseous atom is formed from its element.
I.E: is the minimum energy needed to remove one mole of gaseous electron from one mole of gaseous atom.
Na+ -> Na + e- - 8Energy cycles Born Haber cycle. E.A and Lattice enthalpyE.A: is the enthalpy change that occurs when one mole of gaseous electron is added to one mole of gaseous atom. Cl-> Cl- +e-
L.E: is the enthalpy change that occurs when one mole of solid ionic compound is separated from a gaseous ion under standard conditions. - 9Predicting the Lattice EnthaplyThe higher the lattice enthalpy, as the ionic radius decreases and the ionic charge increases.
- 10Enthalpies change of solutionis the enthalpy change that occurs when one mole of a solute is dissolved in a solvent to infinite dilution under standard conditions.
ionic compounds are soluble in water, as ions are attracted to the polar solvent water.
Hsol=Hhdry + HL.E - 11define entropy (s)refers to the distribution of available energy among particles. the higher the distribution of available energy the higher the entropy.
- 12predicting entropy change valuess-> g entropy increases, as the distribution of energy is increasing, therefore the entropy is positive.
- 13calculating the entropy changes = product - reactant
- 14Gibbs free energy (system)predicts the feasibility of a reaction
= H - TS - 15calculating gibbs free energy reactionGproduct - Greactant