Physical Equilibrium

Relate the concept of equilibrium to physical and chemical systems. Include: conditions necessary to achieve eqlbm. Additional KEY Terms Closed system Dynamic equilibrium Macroscopic

aA + bB cC + dD Kinetic Region Equilibrium Region Concentration te

FEW reactions end with NO reactants and 100% product. Kinetics applies to the speed of a reaction. Equilibrium applies to the extent of a reaction. 2 Na (aq) + Cl2 (aq) 2 NaCl (aq) 2 H2O (g) O2 (g) + 2 H2 (g) FEW reactions end with NO reactants and 100% product. Many reactions proceed in both directions “Reversible”

Balance is (dynamic) equilibrium liquid-vapour equilibrium CLOSED CONTAINER: 1. As more molecules become vapour, the more molecules collide with surface and condense. 2. As evaporation increases - condensation increases until there is a balance. Balance is (dynamic) equilibrium liquid-vapour equilibrium

Dynamic equilibrium exists when the rate of the forward process is equal to the rate of the reverse process. H2O (l) H2O (g) Equilibrium will be reached only with: Reversible reaction Sealed container Constant condition closed system

Saturated solution: A saturated solution is in equilibrium between the undissolved solute and the dissolved solute. Known as solubility equilibrium. C6H12O6(s) C6H12O6(aq)

Any reversible physical process, in which the rate of the forward process is equal to the rate of the reverse process, is known as physical equilibrium. Other examples of physical equilibria include: Vapour Pressure Solubility Solid-liquid (melting point) Liquid-vapour (boiling point)

Chemical Equilibrium

- constant macroscopic properties - Car exhaust: 2 NO2 (g) N2O4 (g) smog smog At equilibrium (te): Rate of the forward reaction EQUALS the rate of the reverse reaction – indefinitely. 2. Concentrations of both reactants and products will be CONSTANT – not same, but constant. - constant macroscopic properties -

aA + bB cC + dD Equilibrium Region Kinetic Region

aA + bB cC + dD Chemical equilibrium: Kinetic Region Equilibrium Region Chemical equilibrium: State where the concentrations of reactants and products remain constant over time because the rates of the forward reaction equal the reverse reaction.

CAN YOU / HAVE YOU? Relate the concept of equilibrium to physical and chemical systems. Include: conditions necessary to achieve eqlbm. Additional KEY Terms Closed system Dynamic equilibrium Macroscopic