GEN CHEM 2 FINAL EXAM - (poopy dookie)

Activation is can be determined by____

measuring the rate constant at a series of different temperatures and making a plot of ln K against 1/T

The Arrhenius equation can be used to ____

convert the rate constant at one temperature to the rate constant at another

If the rate constants are known as two different temperatures, then the Arrhenius equation can be used to determine ______

the activation energy

Not all gas molecules in a sample will move at the _________

same speed

Maxwell Boltzman distribution describes the molecular speeds of ______

gases

Increasing the temperature increases the fraction of gas molecules which have an energy greater than the ______

activation energy

Collision Theory: For a chemical reaction to occur, __(1,2,3)

1. two or more atoms and or molecules must collide

2. with sufficient energy

3. in the correct orientation

Z =

collision frequency

steric factor (p) is a measure of _____

how sensitive a reaction is to the orientation of the reactants.

For reactions in the gas phase, the steric factor is a value between ____

0-1

equation for half life of a zeroth order reaction

equation

equation for the half life of a first order reaction

equation for the half life of a second order reaction

Arrhenius equation (simpler)

Arrhenius equation (two parts)

equation for steric factor

A catalyst is a _____

substance that speeds up a chemical reaction but is not consumed by the reaction (it is there at the end)

Homogenous catalyst:

means that the catalyst is in the same phase as the reactants

Heterogenous catalyst:

means that the catalyst is in a different phase than the reactants

How do catalysts work?

They provide a lower energy pathway for a reaction to occur (lowering the activation energy)

By lowering activation energy, catalysts increase _________ which have sufficient energy to react.

the number of molecules

Heterogenous catalysts are typically _______

transition metals like nickel, gold, silver + onto which the reactants are adsorbed

What is the effect of a heterogenous catalyst?

they weak the bonds in the reactant (lowering the activation energy) and hold the reactant in a particular orientation (increasing the steric factor)

units of zeroth order reaction

M/sec

units of first order reaction

1/sec

units of second order reaction

1/(MxS)

the Arrhenius equation gives activation energy in ____

joules/mol

You can change the spontaneity of reaction by changing the ____ and the ____

temperature and composition

Reaction Quotient

What happens if we add more reactant?

the reaction quotient decreases and G decreases (if you look at formula)

Reaction is spontaneous in the forward direction

what happens if we add more product?

the reaction quotient increases and so does G

reaction is spontaneous in reverse direction

If G=0, then we can control _______

the direction in which the reaction is spontaneous by adding reactant or product

K_c= equilibrium constant + This is_________

the mixture of reactants and products for which the Gibbs free energy change is zero

At equilibrium, the concentrations of _____ and _____ are fixed and not changing

product and reactants

At equilibrium, the rates of the _____ and ______ are the same

forward and reverse reactions

For reactions carried out in the gas phase, the concentrations in the equilibrium constant can be replaced by _____

partial pressures

When writing out the equilibrium constant, do not include ______ or _______

solids or pure liquids

A very small equilibrium constant indicates that the concentration of the products is very _____.

small (equilibrium is on the left hand side)

An equilibrium constant that is very large indicates that the concentration of the products is very ______.

large (equilibrium is to the right side)

if all stoichiometric coefficients in a reaction are multiplied by a number, the equilibrium constant is _________

raised to the power of that number

if two reactions are added together, their equilibrium constants are _______

multiplied together

The reaction quotient Q is a measure of the relative amounts of reactants and products _______

at some point before equilibrium has been reached.

A comparison of ___ and ___ allows us to determine which direction the reaction will shift to reach equilibrium

K and Q

If Q = K, then

the system is at equilibrium

If Q>K, then

there is too high a concentration of products and the reaction is spontaneous in the reverse direction

If Q<K, then

then the concentration of products is too low, and the forward reaction is spontaneous

Le Chatelier’s Principle:

If a stress if exerted on a system in equilibrium, the position of that equilibrium will shift towards reactants or products in order to oppose the stress

What happens when you add reactant? (or remove product)

• equilibrium shifts towards the products

What happens when you add product? (or remove reactant)

• equilibrium shifts towards the reactants

What happens if you increase pressure?

• reaction reduces pressure by reducing the number of gas molecules

  • reaction shifts towards side with fewer gas molecules

What happens if you decrease the pressure?

• increases pressure by increasing the number of gas molecules

• shift towards side with more gas molecules

What happens if you increase temperature and the reaction is exothermic?

• the reaction moves in the direction which takes in heat, to reduce temperature

  • shifts towards reactants

What happens if you decrease the temperature and the reaction is exothermic?

• the reaction moves in the direction which gives out heat, to increase temperature

• shift towards products

What happens when you increase the temperature of an endothermic reaction?

• the reaction moves in the direction which takes in heat, to reduce temperature

• shift towards the products

What happens when you decrease the temperature of an endothermic reaction?

• the reaction moves in direction which gives out heat, to increase temperature

• shift words reactants

when a reaction is reversed, K is the _____

inverse of the K

exothermic reactions view heat as a _____

product

endothermic reactions view heat as _______

reactant

according to the bronsted-lowry definition of acid and bases, anything which ________ is an acid, and anything that ____ is a base

donates a proton, accepts a proton

when acid is added to water, it donates a proton to create ______

a hydrodium ion

conjugate acid:

the base after it accepts a proton

conjugate base:

the acid after it donates a proton

pH is a measure of a solutions

acidity

pH equation

equation to calculate ion concentration from pH

or e

For example, pH 6 has a hydronium ion concentration of

10^-6 = 0.000001M

pH of 7 is a ____ solution

neutral solution

Water is amphoteric, meaning it is able to ________

donate a proton and accept a proton - CAN BE AN ACID AND BASE

Water can auto ionize, meaning that when two molecules of water interact….

one can act as an acid and the other can act as a base

equation Kw representing auto-ionization of water

Kw is the constant for a given temperature.. depends on temp

true lol YAY YAY CA CA

When an acid is added to a solution, it establishes…….

an equilibrium

For strong acids, the equilibrium is far to the ______ and the reaction has gone to _____

right hand side , COMPLETION

_____% of strong acid molecules disassociate in a solution

100%

Strong bases are anything that has ____ and _____

OH and column one or two elements (Li, Na, K)

Strong acids include

Nitrate perches on the suffering of ClBrI

Weak acids are _____

anything else really

weak bases are ______

When a strong acid is involved, the pH of the solution can be determined from _____

the concentration of the acid added

When a strong base is involved, the pH of a solution can be determined from ________

the concentration of base added.

When weak acids or bases are added to water, an _____ is established

equilibrium

Ka is the equilibrium constant for weak acid added to water

Kb is the equilibrium constant for weak base added to water

the further an equilibrium is to the right, the _____ the equilibrium constant (product side)

larger

For an acid, the further the equilibrium is to the right, the ______ the concentration of hydronium ions and the ____ the acid

higher, stronger

The larger the Ka, the ____ the pKa, and the ____ the acid

smaller, stronger

pKa formula:

For a base, the further the equilibrium is to the right, the ___ the concentration of hydroxide ions and the ___ the base

higher, stronger

pKb formula

The Ka of a weak acid is related to the Kb of its conjugate base by the _____

equilibrium constant for the auto ionization of water Kw

Ka is related to Kb in this equation

the conjugate base of a weak acid is a

weak base

the conjugate base of a strong acid is

pH neutral

a cation that is the conjugate acid of a weak base is a ____

weak acid

a cation that is a conjugate acid of strong base is

pH neutral

The pH of an aqueous solution of a salt is a balance between the acid and the base properties of cation and anion

TRUE lol

If a salt is made up of a strong acid and a strong base, it is

pH neutral

If it is made up of a weak base and a strong acid, then it is

acidic

If a salt is made up of a weak acid and a strong base, then it is

weakly basic

If it is made up of a weak acid and a weak base, then

the pH depends on the relative strengths of the acid and base