Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Chemistry 11-13
Chem 141 Chapters 11-13
| Question | Answer |
|---|---|
| Is the rate of reaction consistent over its entire span? | No |
| What is a Factor of reaction rate? | The concentration of the reactants |
| What happens to the reaction rate as the amount of reactants decrease? | It slows down |
| What is Average Rate? | The change in concentration over a period of time |
| What is instantaneous rate? | The Rate at a specific instant in time |
| Dependnece of rate from the concentration of reactants can be expressed in two ways, what are these forms? | Dependence can be expressed via a rate law, in differential or integrated forms |
| What does the rate constant give information about? | Reaction kinetics |
| What is k dependent on? what does a large and small indicate?what are the units of k? | K is temperature dependent, a large k means a fast reaction, a small k means a slow reaction, the units of k depend on the order of the reaction. |
| What is the method of initial rates? | The initial rate of a reaction is measured using varying concentrations of reactants. |
| What is the integrated rate law? | Allows us to determine the concentration as a function of time, the form of the integrated rate law depends on the order of the reaction |
| What is a zero order reaction? | Rate is independent of reaction, k=m/s, and the slope of this plot (A) vs t is k=-slope |
| What is a first order reaction? | Plot of ln(A) vs t gives a straight line, showing the reaction is first order. Its units are k=1/s k=-slope |
| What is a second order Reaction? | a plot of 1/(A) vs t will be linear and k=slope the units are 1/ms |
| What is Half Life? | The time needed for the concentration of a reactant to fall to one half of its original value |
| What is the rate o reaction primarily impacted by? | Temperature |
| What happens to the rate of reaction as temperature increases? | the rate of reaction speeds up |
| What must happen for a reaction to take place? | Molecules must collide with a minimum level of energy for a reaction to occur, when the temperature increases, this intern increases the kinetic energy letting more molecules meet that minimum energy requirement. |
| What is Activation energy? | The minimum energy required to trigger a reaction |
| How does a reaction with a larger activation energy compare to one with a lower activation energy? | The reaction with a larger activation energy will run slower because fewer collisions have the required energy. |
| How can the geometry of molecules impact the reaction? | Because Molecules may need to collide in a proper orientation |
| What does the arrhenius equation do? | Relates the rate constant to temperature |
| How to find activation energy? | Ea=-slope*R where R is the gas constant of 8.314 J/mol K |
| What are reaction mechanisms? | A collection of one or more molecular steps that account for the way reactants become products |
| What is each step know as in a reaction mechanism? | An elementary reaction, and the coefficients in an elementary reaction give the rate law exponents for that step. |
| What are the three types of elementary steps in reaction mechanisms? | Unimolecular-One reactant Bimolecular-Two reactants Termolecular-three reactants |
| What are the two characteristics of a reaction mechanism? | A chemical species is generated in one step and consumed in a later step is called a reactive intermediate. When the steps of the mechanism are properly summed, they give the observed stoichiometry of the overall reaction. |
| What is the rate determining step? | The step in the mechanism that runs the slowest limiting the rate of the reaction. |
| What must be true for a mechanism to be valid? | The rate law must match what is observed experimentally. |
| What is a catalyst? | A substance that increases the rate of a reaction but is neither created nor destroyed in the process. |
| What are the three main properties of a catalyst? | it is not part of the reaction stoichiometry, it is not consumed by the reaction, and it increases the rate of the reaction |
| What is a homogenous catalyst? | The catalyst in the same phase as the reactants |
| What is a heterogenous catalyst? | The catalyst is in a different phase than the reactant. -Reactants absorb on the catalyst surface -Reactants migrate on the surface until encountering each other and react -the products desorb from the surface. |
| How does a catalyst change the mechanism of a reaction? | A catalyzed mechanism will have a lower activation energy causing a faster reaction. |
| What should be considered when selecting a catalyst? | Longevity to last many cycles should deteriorate over time should have a high turnover rate should be selective, meaning it speeds up desired reaction |
| What is chemical equilibrium? | When the amounts of reactants and products is no longer changing. OR the rate of reactants converted to products and products back to reactants are equal. AND the process is dynamic, meaning both reactions are constantly occurring. |
| What is the equilibrium constant? | The ratio of the concentration of the products and reactants once the equilibrium has been reached. its value indicated whether the reaction is product or reactant favored. |
| For what values does k value products or reactants? | K>1000 means mostly products K<0.001 means mostly reactants |
| When writing the equilibrium expression, what components are included? | ONLY aqueous (aq) and gas phases (g) |
| What is the Reaction quotient? | Basically, the same as the equilibrium constant, but the reaction does not need to be at equilibrium. Can be Compared to k to determine if a reaction is forward or reverse favored. |
| What does it mean if Q>K? | Reverse reaction is favored |
| What does it mean if Q=K? | System is at equilibrium |
| What does it mean if Q<K? | Forward reaction is favored |
| What is Homogenous equilibrium? | An equilibrium where all species are in the same state. |
| What happens to K if a reaction is reversed? | The expression of K is inverted |
| What does changing stoichiometric coefficients in an equation do to the exponents of the expression? | It changes them. |
| When two reactions are combined what happens to the equilibrium expression? | The new equilibrium expression will be the product of the expressions of the two reactions. |
| What can the equilibrium constant be used for? | Can be applied to determine the concentrations of the reactants and products once equilibrium has been reached |
| What is Le Chateliers principle? | when a system at equilibrium is stressed, it responds by reestablishing equilibrium to reduce the stress. |
| What are the three common means to introdcue stress in chemical equalibrium? | Increase concentration, temperature, or pressure |
| What happens in a reaction in chemical equilibrium if products or reactants are added or removed? | If they are added, the reaction will shift to use up the added component. If they are removed, the reaction will shift to replace the component that was removed. |
| What happens in a chemical equilibrium if pressure is increased or decreased? | An increase will make the reaction shift to decrease the pressure, and will move to the side with fewer moles of gas. A decrease in pressure will make the reaction shift to increase pressure, moving to the side with more moles of gas. |
| What happens in a chemical equilibrium if the temperature changes? | increasing temperature adds heat to the system decreasing temperature is removing heat from the system. This has a similar effect on the system to changing the products or reactants. |
| How is heat treated in an exothermic vs endothermic reaction? | Exothermic-heat is treated as a product endothermic-heat is treated as a reactant |
| What are the 3 effects of a catalyst on equilibria? | A catalyst does not impact the position of an equilibrium A catalyst speeds up both forward and reverse reactions equally the system will reach equilibrium faster. |
| What is the qualitative aspect of solubility? | Is it simply soluble or insoluble? |
| What is the quantitative aspect of solubility? | All salts dissolve to a certain extent |
| What is Ksp, and what are its implications? | Solubility product constant, it varies with temperature and a greater Ksp means that salt is more soluble. |
| What is molar solubility? | The concentration of a dissolved salt in a saturated solution. |
| What happens to solubility as temperature increases? | Solubility increases. |
| What is the Common Ion Effect? | The presence of an ion already in the solution that is also in the salt you want to dissolve. In general, this will reduce the solubility of the salt. For example, AgCl is less dissolvable in a solution of NaCl. |
| What did Arrhenius say an acid and base was? | Acid-a substance that dissociates yielding a proton when dissolved in water. Base-a substance that dissociates yielding hydroxide when dissolved in water. |
| What do Bronsted-Lowry say an acids and bases are? | Acid-A substance that donates a proton Base-A substance that accepts a proton. |
| How do acids interact with water? | They give it a proton |
| How do Strong acids vs weak acids act in a reaction | Strong acids react one way Weak acids form an equilibrium |
| How do bases interact with water? | They take a proton from water forming a hydroxide ion |
| What is a conjugate Acid? | The compound that forms when a base accepts a proton |
| What is a conjugate base? | The compound that forms when an acid donates a proton |
| What is an Amphoteric substance? | A substance that can act either as an acid or a base. An example of this could be water. |
| The strength of weak acids and bases is governed by what? | An equilibrium constant where Ka is acid dissociation constant and Kb is base dissociation constant |
| What can the acidity of a solution be expressed by? | The PH scale from 0-14 that is related to the concentration of H3O in the solution. |
| What is the PH of Water? | 7.00 |
| What are Oxidation/Reduction reactions? | A type of reaction that involves the transfer of electrons, both oxidation and reduction are required. |
| What is oxidation? | The loss of electrons(s) |
| What is reduction? | The gain of electron(s) |
| What do reactants do in a Oxidation/Reduction reaction? | One reactant acts as a reducing agent, and the substance is oxidized, one reactant acts as an oxidizing agent and the substance is reduced. |
| What is a Galvanic Cell? | An electrochemical cell where a spontaneous chemical reaction can be used to generate an electrical current. In a galvanic cell each half of the reaction is prepared in sperate half cells. A salt bridge is used to connect the half cells. |
| What is Galvanic Cell notation? | A single line represents the phase boundary within the half cell A double line represents the salt bridge between the two half cells. The Anode is always listed first. |
| Galvanic Cell Notation | Anode | Anode Solution || Cathode solution | Cathode |
| What is G in a galvanic cell reaction? | Always negative because the galvanic cell is spontaneous |
| What is a battery? | A cell or series of cells that generate an electrical current. Batteries harness the electrical work of a galvanic cell. |
| What is a primary cell? | Single use batteries that cannot be recharged. |
| What is a secondary cell? | Battery that can be recharged once it is depleted. |
| What is a Nickel Metal Hydride battery? | Anode consists of a metal hydride, cathode is nickel based with a complex reaction. |
| What is a lead acid storage battery? | It has a Lead Anode, and a Lead(IV) Oxide cathode. |
| What is a Lithium Ion Battery? | Anode is a lithium graphite framework; Cathode is a cobalt oxide embedded with lithium |
| What is Electrolysis? | Process that passes current through an ionic solution or molten salt to produce a chemical reaction. This changes polarity of electrodes in a system. |
| What are electron interactions during electrolysis? | Electrons are forced to the cathode making it negative Electrons are pulled from the anode making it positive. |
| What is Passive electrolysis? | Electrodes composed of inert materials that provide a pathway for electrons. |
| What is Active electrolysis? | Electrodes are part of the process. This is seen in electroplating. |
| What is the Hall Herouldt refining process? | Uses carbon electrodes as inert sites for passive electrolysis. This produces aluminum and oxygen gas, but a drawback is that it makes CO2 |
Created by:
user-2007051