University:
York University
Course:
CHEM 1001 | Chemical Dynamics
Academic year:

2022
Views:

53

Pages:

2
Author:

Niklas

Chapter 17 / Chapter 15 03/25/2022 03/30/2022 Ion-pairing in salt solution assumed salts dissociate completely when they dissolve ion-pairing lowers effective concentration of particles Van't Hoff factor (i) = number of ions per molecule Osmotic pressure: π = iMRT Chemical Kinetics thermodynamics tells us whether a reaction can occur but doesn't tell how fast it occurs kinetics: the science of reaction rates of reaction mechanisms Average vs. Instantaneous rates rate: change that occurs in a given interval of time instantaneous rate: always changing chemical rate laws describe instantaneous rates Chapter 15 03/30/2022 rate of disappearance do not divide by stoichiometric coefficient factors that affect reaction rate the reactants chemical identity, physical state concentration of reactants increasing concentration = faster rate temperature increasing temperature = faster rate presence of a catalyst Effect of concentration rate law: relationship between rate of a reaction and concentrations of its reactants A + B -> C + D rate = k[A]^x[B]^y k = rate constant independent of [A] and [B]; varies with temperature x and y are exponents typically 2 or 0, not necessarily integers not usually stoichiometric coefficients found through experimentation and mechanisms (not fully proven) Reaction order determined by rate law exponents rate = k[A]^x[B]^y overall order of reaction: x + y units of rate: units of k are dependent on the right side of equation first: s^-1 (nuclear decay, unimolecular reaction) second: M^-1s^-1 (two molecules need to encounter each other) third: M^-2s^-1 (two molecules that collide, collide into something else)