Phys Kinetic Energy Notes

Kinetics Notes Kinetic Energy  Related to _____________ ________________  ◦ Higher velocity (_________)= higher energy Reaction Rate  The rate of reaction tells the _____________ at which the reaction takes place Collision Theory  _____________ __________ states that atoms, ions, and molecules must _____________ in order to react  Not every collision between atoms and molecules results in a reaction!   Example: CO (g) + NO2 (g)  CO2 (g) + NO (g)  Any change that _______________the number of collisions should _____________ the reaction rate Factors in reaction rates… 1. What are their tendencies towards bond formation? a. Cs + H2O -----> CsOH + H2 i. b. Cs  very reactive(low IE, EN) c. Fe + H2O -----> Fe2O3+ H2 i. 2. The ability of reactants to meet (collide) a. Reactions usually occur in ____________, ___________, or _______________ phase b. Related to ___________ ________ i. _____________surface area means ____________ reaction in heterogeneous reactions 1. Reactions only occur at phase interface 3. a. Often listed as ________________ i. Written as square brackets [ ] 1. The moalrity (concentration) of HBr = b. More reactants = _______________ _______________ c. __________________ ________________ = increases reaction rate 4. a. Temperature is a measure of ______________ _______________ _____________ i. Higher T means higher _______ b. Faster moving molecules means _____________ _______________ c. More collisions means a ______________ ________________ _____________ 5. Catalyst a. _____________ the reaction rate without being consumed in the process b. Lower the energy needed to react (Ea) c. Lower activation energy means more collisions between particles have ________________ _____________ __________ ______________. Types of catalysts  A ___________________ catalyst exists in a physical state different than that of the reaction it catalyzes.  A ___________________ catalyst exists in the same physical state as the reaction it catalyzes.  A __________________ catalyst is consumed in the reaction, but then re-made  An __________________ is a biologically active catalyst  An _________________ slows down a reaction by increasing the activation energy To review, the 5 factors that determine reaction rate are… 1. 2. 3. 4. 5. Now with numbers…. Measuring reaction rates  A rate is _______________ _____ ________ ____ _______  ◦ interest rate = $ earned / time ◦ speed = distance traveled/ time ◦ pay = dollars / hour as the reaction proceeds, the reactants are “used up” ◦ ◦  Reaction rate is measured as : ◦ ◦ (mol/L)/s, M/s, or mol L-1s-1 Coefficients and rates  The coefficients of a chemical equation give us some insight as to the relative rates of consumption of reactants and production of products, ____________ _________ _______________ _____________! 2A + B  3C + 2D  It takes 2 A’s for every single B that reacts, so A is “disappearing” twice as fast as B is  There are 2 D’s produced for every B and every 2 A’s that are “consumed”, so D is appearing at the same rate A is disappearing and twice as fast as B is disappearing  C is being produced 3 times faster than B is being used up, and 3/2 times faster that A is being used up Rate law  A __________ ________ is an equation that describes how a change in concentration affects the reaction rate. ◦ for the reaction A + B products ◦ The rate law would be: ◦ rate = k[A]m[B]n rate = k[A]m[B]n  k=  m=  n=  m and n have to be experimentally determined; they are not the same as the reaction coefficients except by coincidence.