Chemistry- Exam 3 Review

Solutions

transparent, do not separate, contain small particles, ions, or molecules that cannot be filtered, cannot pass through semipermeable membranes.

Colloids

medium sized particles, cannot be filtered, can be separated by semipermeable membranes.

Suspensions

heterogenous, nonuniform mixtures, have very large particles that settle out of solution, can be filtered, must be stirred to stay suspended

ex: blood platelets

hypotonic

a solution with a lower solute concentration than that in another solution, lower osmotic pressure

a hypotonic red blood cell gains water, swells up, and bursts

hypertonic

a solution with a comparatively greater solute concentration than that in another solution, greater osmotic pressure than the other.

hypertonic red blood cell loses water and shrinks.

isotonic

water comes in and out at an equal rate

isotonic red blood cell retains normal volume

Adding Reactants

rate of the forward reaction increases to from more product until the system is again at equilibrium.  

Equilibrium shifts towards the products

Removing Reactants

The rate of the reverse reaction will increase to form more reactant until equilibrium is reached.  

Equilibrium shifts toward reactants.  

Removing Products

There is a decrease in collisions of product molecules 

Rate of forward reaction therefore increases to form more product 

Shifts toward products.  

Adding Products

There is now more product, so the reaction will shift toward reactants to reduce the added product.  

Shift toward reactants.  

Adding a Catalyst

speeds up reaction by lowering activation energy, does not change equilbirum

Decreasing Volume

only in gases, decreasing volume increases the concentration of the gases, so the system shifts in direction of the smaller number of moles to compensate

Increasing Volume

only in gases, increasing volume decreases concentration, so the system shifts in the direction of the larger number of moles to compensate

Decreasing Temperature Endothermic

Decreasing temperature of endothermic reaction causes the system to shift the reaction toward more heat.  

Shifts reaction toward reactants, increasing heat in system.

Decreasing Temperature- Exothermic

Decreasing temp of exothermic reaction causes the system to respond by shifting the reaction toward more heat 

Shifts reaction toward the products, increasing heat in system.  

Increasing Temperature Endothermic

Increasing temperature of an endo reaction causes the system to respond by shifting the reaction to remove heat.  

Shifts the reaction toward the products, using up heat.  

Increasing Temperature Exothermic

Increasing temp of an exothermic reaction causes the system to responds by shifting the reaction toward removing heat.  

Shifts reaction toward the reactants, decreasing heat in system.  

Arrhenius Acids

• Produce hydrogen ions (protons) when they dissolve in water. 

• Electrolytes, because they produce H+ in water 

• Sour taste, turn blue litmus red, corrode some metals 

Naming acids with a hydrogen ion and nonmetal ion

named with prefix hydro and end with -ic acid

HCl- hydrochloric acid

Naming acids with a hydrogen ion and a polyatomic ion

change the end of the name of the polyatomic ion from

-ate to -ic acid or -ite to -ous acid

HClO3- chloric acid

HClO2- chlorous acid

Arrhenius Bases

• Produce hydroxide ions (OH-) in water 

  • Also electrolytes 

• Taste bitter or chalky, soapy and slippery, turn litmus paper blue and phenolphthalein pink 

Bronsted-Lowry Acids

acids donate a proton (H+) in aqueous solutions

Bronsted-Lowry Bases

Bases accept a proton (H+) in aqueous solutions 

Conjugate Acid

base that gains a proton

gain a H+ and have a 1+ charge when compared to the base

H2O (base) → H3O+ (con acid)

Conjugate Base

acid that loses a proton

lose a H+ and have a -1 charge when compared to the acid

HCl (acid) → Cl- (con base)

Strong Acids

• HNO₃ - nitric acid

• H₂SO₄- sulfuric acid

• HClO₄- perchloric acid

• HCl- hydrochloric acid

• HBr- hydrobromic acid

• HI- hydroiodic acid

Strong Bases

Formed from metals of Group 1 and 2

• NaOH- sodium hydroxide

• LiOH- lithium hydroxide

• KOH- potassium hydroxide

• Rb and CsOH- rubidium and cesium hydroxide

• Ba(OH)₂- barium hydroxide

• Ca(OH)₂- calcium hydroxide

• Sr(OH)₂- strontium hydroxide

Weak Bases

include NH₃

Solvent

substance present in larger amount

ex: water

Solute

substance present in a smaller amount

Electrolyte

substances that produce an electrically conducting solution when dissolved

Strong Electrolyte

dissociate (split into cation and anion) 100% in water, conduct a strong electric current.

Weak Electrolyte

dissociate slightly in water, forms a solution with a few ions and most undissociated molecules, weak electric current

Nonelectrolytes

substance that does not ionize in solution, dissolve as molecules in water, do not produce ions, no electric current

Unsaturated Solution

contain less than maximum amount of solute, can dissolve more solute

Saturated Solution

contain the maximum amount of solute that can dissolve, have undissolved solute at the bottom of the container.

Supersaturated Solution

contain more than the maximum amount of solute, due to how the solution was created- excess heat or pressure.

Henry’s Law

solubility of a gas in a liquid is directly related to the pressure of the gas above the liquid.

at higher pressures, more gas dissolves

when pressure of a gas above a solution decreases, the solubility decreases

Dilution Equation

C1 x V1 = C2 x V2

Osmosis

water (solvent) flows from a lower to a higher solute concentration.

Chemical Equilibrium

the rate of the forward reaction is equal to the rate of the reverse reaction

Equilibrium Expression, Dissociation of Acid or Base

Large Kc (equilibrium constant)

at equilibrium, the reaction mixture contains mostly product and few reactants 

Small Kc (equilibrium constant)

at equilibrium, the reaction mixture contains mostly reactants and few products 

Kc near 1 (equilibrium constant)

at equilibrium they have about equal concentrations of reactants and products

Acid Dissociation Constant

• If it is less than one, the equilibrium lies to the left, favoring the reactants. 

• Greater than one, the equilibrium lies to the right, favoring the products. 

• Weak acids have small Ka values, while strong acids have very large Ka value. 

Base Dissociation Constant

• If it is less than one, the equilibrium lies to the left, favoring the reactants. 

• Greater than one, the equilibrium lies to the right, favoring the products. 

• The stronger the base is, the large the Kb value 

Water Dissociation Expression

Acidic Solution

H30+ is larger than OH-

Basic Solution

OH- is larger than H3O+

pH

• pH = -log[H3O+] 

• pH = -log[H+] 

• pH = -log[OH] - 14

[H3O+] =

10^pH

(1×10^-14) / [OH-]

[OH-] =

1x10^14 / [H3O] 

Molarity

moles of solute / liters of solution

pH of a Buffer

Ka (acid dissociation constant) x weak acid / conjugate base to get [H3O]

Then put into: pH is the –log(H3O+) 

Hemolysis

in a hypotonic solution, water rushes into the cell causing it to burst.

Crenation

in a hypertonic solution, water rushes out of the cell causing it to shrink

Buffers Consist Of

a weak acid and its conjugate base

Function of Weak Acid in Buffer

If a small amount of base is added to this same buffer solution, it is neutralized by the acetic acid, which shifts the equilibrium in the direction of the product’s acetate ion and water. 

Function of Conjugate Base in Buffer

If a small amount of acid is added to this same buffer solution, it is neutralized by the acetate ion, which shifts the equilibrium in the direction of the reactants acetic acid.