AP Chem Ch 11-12 Flashcards

Question

Osmotic pressure

Answer 1

The minimum pressure that stops the osmosis The volume of the solution increases while the volume of the solvent decreases. At equilibrium, there is a greater hydrostatic pressure on the solution than on the pure solvent. Excess pressure is the osmotic pressure. Pi = iMRT Where I is vant hoff factor, M is molarity of the solution, R is constant (.0821) and T is temperature in Kelvin

Answer 2

Solutions with identical osmotic pressures

Answer 3

Hyper is more solute, hypo is less solute

Answer 4

I, the number of ions, always needs to be included in the colligative property equations

Answer 5

Suspension of tiny particles in some medium

Answer 6

Light scatters in a colloid but not in a pure substance

Answer 7

From the Nitrogen cycle, the Haber Basch Mitasch process, we see how important reaction rates are, as we need to get the reactions done in order to feed the human population

Answer 8

Increase temp, increases rate, also pushes equilibrium to favor the reactants (increased temperature favors the side of the reaction with more gas molecules)

Answer 9

Favors the products (higher pressure favors the side of the rxn with fewer gas molecules)

Answer 10

The study of reaction rates

Answer 11

The change in a given quantity over a specific period of time GOAL is to understand the steps by which a rxn is taking place or the rxn mechanism

Answer 12

Change in molarity / change in time That's the rate at a given time Use integrated rate laws to get concentration depending on time

Answer 13

For non-zeroth order reactions, as time goes on, there is less concentration of the starting material, and collisions are thus less likely to occur, so it takes longer for the rxn. The rate decreases as time goes on and concentration lowers

Answer 14

Rate = k* [A]^n K is the rate constant, differs for each reaction N is the order of the reaction, determined experimentally If more than one reactant, rate = k* [A]^n * [B]^m Note: need to do initial rates to not use reverse reaction

Answer 15

Differential shows how the rate of a reaction depends on concentration. Rate = k [A]^n Integrated rate law shows how the concentration of species in the reaction depend on time. We study under conditions where reverse reaction is not important -- just use reactant concentrations

Answer 16

Need to plot the data (M vs Time) and get the tangent line at the given point -- that's the rate If can't graph, then If no correlation between M and time, then zeroth If ln[A] and t produce a linear relationship, then first order If 1/[A] and t produce a linear relationship, then second order Can also do slope and see if get same values for different values (pick three points and make sure get same slope when subtract each)

Answer 17

Pick experiments when A has same concentration and B has different Then rate 2/ rate 1 = [B2]^n / [B1]^n Plug in and find n Then do same where b stays same and A changes, and calculate p Then plug into overall equation -- rate = k [A]^p * [B]^n And calculate k plugging in data from any experiment

Answer 18

Sum of the individual orders

Answer 19

How the concentration depends on time. Concentration as a function of time

Answer 20

1st and 2nd order are on the reference table --> 1st is with ln vs r and second is with 1 / [A] vs t Zeroth --> [A] = -kt + [A0] [A] vs t

Answer 21

Time required for a reactant to reach half its original concentration

Answer 22

Half life is when half the substance is left, so [A]t = [.5A0]. Plug that in for [A]t and we can then calculate t in terms of k (in terms of A0 as well for 0th and 2nd order reactions) First order equation is on reference table

Answer 23

Series of steps in a chemical reaction | Kinetics helps to elucidate a reaction mechanism.

Answer 24

Species generated and consumed during a reaction.

Answer 25

A reaction whose rate law can be determined from its moleculaity, the number of species that must collide to produce the reaction indicated in the elementary step. The coefficient is the order in a given elementary step Note: rate cannot be in terms of an intermediate. Needs to be a real reactant.

Answer 26

Slowest step in a reaction, the rate is dependent on it. The rate of the overall reaction = rate of the RDS

Answer 27

1. The sum of the elementary steps must give the overall balanced equation for the rxn 2. The mechanism must agree with the experimentally determined rate law.

Answer 28

1. Concentration of material for non-zeroth order --> increase concentration, rate increases 2. Temperature--> more molecules with high enough Energy 3. Collisions with higher energy 4. Orientation of molecules -- overcome activation energy

Answer 29

Higher temperature speeds up a reaction Think about boiling at sea level vs altitude. At altitude, Lower pressure in the atm, so boiling point less, and thus it takes longer to boil because less energy in the system. More collisions at higher temperature

Answer 30

A model used to account for the observed characteristics of reaction rates. Model is built around the central idea that molecules must collide to react. Found that only a small fraction of the collisions produces a reaction. This because of a threshold energy, the activation energy, that must be overcome for a reaction to occur. Energy to break the bonds comes from kinetic energies possesses by reacting molecules before the collision. Kinetic energy changed to potential energy as molecules are distorted during collision to break bonds and rearrange the atoms into the product molecules.

Answer 31

Energy that must be overcome to produce a chemical reaction.

Answer 32

Important in determining reaction rates Observed reaction rate is considerably smaller than raye of collisions with enough energy to surmount the barrier. Many collisions, even though they have required energy, still do not produce a reaction. Because of the molecular orientation. While some orientations lead to reaction, others do not. Thus, need a factor in our equation to allow for this.

Answer 33

1. Have enough energy, collision energy >= to the activation energy. 2. Relative orientation of the reactants must allow formation of any new bonds necessary to produce products.

Answer 34

K, the rate constant, = z * p * e ^ (-Ea/RT) Z is the collision frequency and p is the steric factor Ea is activation energy (joules) R is gas constant (8.31) T temperature in Kelvin A = zp So, k= A * e^ (-Ea/RT) Ln (k) = -Ea/R (1/T) + ln(A) Linear relationship of ln (k) vs (1/T) with slope -Ea/R

Answer 35

ln (K2/K1) = (Ea/R) (1/T1 - 1/T2)

Answer 36

Something added to a reaction to lower the activation energy. Facilitate materials to be oriented correctly Catalyst not consumed during reaction (amount before = amount after) Creates a new mechanism with the reaction--> alternate pathway with a lower activation energy than the uncatalyzed reaction

Answer 37

Homogenous --> catalyst and reactant in the same phase (both solids for example) Heterogenous means they're in different phases

Answer 38

1. Adsorption and activation of the reactants. 2. Migration of adsorbed reactants on the surface 3. Reaction of adsorbed substances 4. Escape, or desorption, of the products

Answer 39

Adsorption is the collection of one substance on the surface of another Absorption is the penetration of one substance into another.

Answer 40

Reactants to peak is activation energy Reactants to products is delta E Delta E positive when products have more energy, higher up Delta E negative when products lower than reactants; products have less energy

AP Chem Ch 11-12 Flashcards

(64 cards)