2.1 - Gases
2.2 - Kinetic Molecular Theory
2.3 - Real Gases
2.4 - Chemical Kinetics
2.5 - Collision Theory
2.6 - Equations for REaction Rates
2.7 - Determining the Rate Law by Experiment
2.8 - Recognizing Reaction Orders
2.9 - Rates of Reversible Reactions
2.10- Catalysis
2.11 - Effects of Solvent on Rate
2.12 - Equilibrium
2.13 - The Partial Pressure Equilibrium Constant
2.14 - The Reaction Quotient
2.15 - Le Chatelier's Principle
Terms : Hide Images
| 775921170 | What is the standard temperature and pressure (STP) ? | 1. 0 degrees C 2. 1 atm | |
| 775921171 | In the Kinetic Molecular Theory, we have the model of an ideal gas. What are the 4 characteristics of an ideal gas? | 1. ideal gases have 0 volume 2. Gas molecules exert no forces other than repulsive forces due to collisions 3. Elastic collisions only made 4. EK of gas molecules proportional to T | |
| 775921172 | What is the Ideal gas Law equation? | PV = nRT - P: in atm - V: in L - n: number of moles of gas - T: in K - R: 0.08206 L atm/ Kmol or 8.314J/Kmol | |
| 775921173 | At STP, one mole of any gas behaving ideally will occupy how many L? | 22.4 L standard molar volume | |
| 775921174 | What is partial pressure and its equation? | Partial pressure of a gas is the total pressure of the gaseous mixture times the mole fraction of the particular gas. Pa = XaPtotal - Xa = mole fraction | |
| 775921175 | What is Dalton's law? | States that the total pressure exerted by a gaseous mixture is the sum of the partial pressures of each of its gases. Ptotal = P1 + P2 + P3... | |
| 775921176 | What is the equation for the average translational kinetic energy of a gas? | KEavg = 3/2 RT - This is for a mole of gas molecules and not the energy of every or any of the molecules | |
| 775921177 | What is Graham's law? What is the equation for it? | Graham's law is the relationship that gives the ratio of the rms velocities of two gases in a homogeneous mixture. v1/v2 = sqrt(m2/m1) - Avg speed of molecules are inversely proportional to the sqrt of the mass. | |
| 775921178 | What is the difference between effusion and diffusion? | 1. Effusion is the spreading of a gas from high pressure to low pressure through a pinhole. - Molecules with higher rms velocity will experience more collisions with container walls, the rate the gas will find the pinhole will be greater 2. Diffusion is the spreading of one gas into another gas or into empty space. | |
| 775921179 | What is the equation for effusion rate/diffusion rate as predicted by Graham? | - Same as Graham's equation: effusion rate 1/ effusion rate 2 = sqrt (M2/M1) | |
| 775921180 | What are 2 ways real gases deviate from ideal behavior? | - When gases are pushed close together, they exhibit nonideal behavior. 1. V real > V ideal molecule because real gases do have V, their V must be added to the ideal V. 2. Real gases do exhibit forces on each other and are attractive when molecules are far apart, pulling them inward so they strike the container with less force. Preal < Pideal | |
| 775921181 | For 1 mole of ideal gas, how does volume cause ideal behavior to deviate? | Volume causes PV/RT to deviate positively from ideal behavior because V increases. Real gases occupy volumes greater than predicted, especially as Pressure increases, gas V takes a larger fraction of total space. | |
| 775921182 | For 1 mole of ideal gas, how does intermolecular forces cause deviations of ideal behavior? | Intermolecular forces cause PV/RT to deviate negatively from ideal behavior because the pressure/force of molecule against the wall of the container is less than 1. | |
| 776330703 | What is the difference between Kinetics and themodynamics? | 1. Kinetics deals with the rate of a reaction as it moves toward equilibrium and tells us how fast equilibrium is achieved. 2. Thermodynamics deals with the balance of reactants and products after they have achieved equilibirum - tells us what equilibrium looks like. -Lower Ea forms kinetic products but thermodynamically favored products have lower energy/more stability. | |
| 776330704 | What are the 2 requirements for a given collision to create new molecules in a reaction? | 1. The relative kinetic energies of colliding molecules reach a threshold energy called activation energy 2. Proper spatial orientation | |
| 776330705 | What does the rate of a reaction tell you? What are the units? | How quickly the concentration of a reactant or product is changing. Molarity (mol/Ls) | |
| 776330706 | What are intermediates? | Species that are products of one reaction and reactants of a later reaction in a reaction chain. They are often unstable and react as quickly as they're formed. | |
| 776330707 | What is the rate law reaction for only the forward reaction? | rate = k[A]m[B]n | |
| 776330708 | What is meant by 0 order? | When there's no reverse reaction, 0 order reactions have a constant rate that is independent of the concentration of the reactants. | |
| 776330709 | What is 1st order? | rate is directly proportional to the concentration of the reactant. Doubling the concentration increases the rate by a factor of 2 | |
| 776330710 | What is 2nd order? | the rate is to the square of the concentration of the reactant. Doubling the concentration increases the rate by a factor of 4 | |
| 776330711 | What does rate constant "k" tell you? What are the 2 things it's dependent on? | "k" is called the rate constant. It is independent of the other quantities in the equation. It is dependent on: 1. the nature of the reaction "fast" reactions typically have large rate constants if k is small, the reaction is slow at ordinary concentration 2. the temperature ordinarily, k increases with temperature | |
| 776330712 | What is the rate determining step? | The rate of the slowest step determines the rate of the overall reaction. Steps after the rate determining step make no contribution to the rate law but steps before do, so we have to include the intermediate in the determination of the rate law. | |
| 776330713 | What is a catalyst? | A substance that increases the rate of a reaction in both directions without being consumed or altered. When the Ea is lowered, more collisions have sufficient relative kinetic energy to create a reaction. | |
| 776330714 | What are 2 phases of catalysts? How can we increase reaction rates using either catalyst? | 1. Heterogeneous catalyst - in a different phase than reactants and products. (i.e. solids) that allow reactants to adsorb to its surface. Reaction rates can be increased by increasing surface area. 2. Homogeneous catalyst - same phase as reactants/products (usually gas/liquid). Increasing concentration of the catalyst increases rate of reaction. | |
| 776330715 | What is the effect of solvent on reaction rate of a liquid | Rate constant in a liquid is a function of the solvent as well as temperature. Solvents surround the liquid like a cage and the liquid must escape before reacting with another reactant. Thus, collisions in a liquid occur at about the same rate as in a gas. | |
| 776596610 | What is the rate at equilibrium? | 0 b/c forward rate = reverse rate | |
| 776596611 | In what type of reaction CAN you use the stoichiometric coefficients as the reaction orders in the rate law equation? | Elementary reactions (single step) and not multistep because you can have a reactant that appears in the overall reaction but does not appear in the slowest step of that mechanism, then that reactant is zero order and will not appear in the rate law. | |
| 776596612 | What is the law of mass action? Write the equation for it. | Kc=[C]c[D]d/[A]a[B]b States that the rate of an elementary reaction and non-elementary is proportional to the concentrations of the participating molecules during an equilibrium reaction. If it's an equilibrium rxn, then the above ratio is a constant. - K has no dimensions | |
| 776596613 | What is the difference between rate constant k and equilibrium constant K? | Rate constant tells you the speed of the reaction. Equilibrium constant tells you when the reaction is at equilibrium. | |
| 776596614 | Equilibrium constant depends on? | Temperature only! Not pressure! If the forward rxn is exothermic, increasing temperature decreases K (by being less product favored). If the fwd reaction is endothermic, increasing T increases K. | |
| 776596615 | Why are pure liquids or solids given a value of 1 for the equilibrium? | This is because they do not effect the reactant amount at equilibrium in the reaction, so they are disregarded and kept at 1. | |
| 776596616 | The equilibrium constant describes only equilibrium conditions. What is used when the reaction isn't at equilibrium? What is the equation? | Reaction quotient Q is used to predict the direction a reaction will proceed to equilibrium. Q = products ^coefficients/ reactants ^coefficients | |
| 776596617 | If K=Q? | Reaction is at equilibrium | |
| 776596618 | If Q>K? | The ratio of products is greater than reactants so the reverse reaction is favored. | |
| 776596619 | If Q| The ratio of the products to the reactants is lower - there are more reactants than products. The forward reaction is favored. | | |
| 776596620 | What does Le Chatelier's principle state? | When a system at equilibrium is stressed, it'll shift in a direction that will reduce that stress. | |
| 776596621 | What are the 3 stresses in Le Chatelier's principle? | 1. Addition/Removal of a product or reactant 2. Changing the pressure of the system 3. Heating or cooling the system | |
| 776596622 | Which direction is the shift predicted by LC's principle if the pressure is increased? If pressure is decreased? | 1. It will shift to the side with fewer moles. 2. It will shift to the side with more moles | |
| 776596623 | Why does adding a nonreactive gas not shift the equilibrium even though pressure increases? | Adding an inert gas does not change the partial pressures and total pressure increase doesn't have an effect on the equilibrium constant. Only partial pressures have an effect | |
| 776596624 | Why does LC's Principle not predict shift during solvation reactions? | Solubility of salts increase when temperature increases, even when reaction is exothermic. Equilibrium will shift to the right when it's predicted not to. |
