What is the molar mass of any gas at STP?

22.4 L

What is STP?

Standard Temperature and Pressure

Temp:273 K

Pressure: 1atm

The total pressure of our atmosphere is equal to

the sum of the pressures of which gases?

N2 and O2

Do nonpolar or polar gases behave more ideally?

Nonpolar because attractive forces are present in polar gases.

What is a surfactant?

A substance added which decreases surface tension.

What is the triple point?

The temp and pressure at which a substance can exist in equilibrium in the liquid, solid and gas state.

Evaporation

The process of conversion of a liquid to gas at a temp too low to boil.

Condensation

Conversion of gas to the liquid state.

 Liquid water in equilibrium with water vapor.

When the rate of evaporation equals the rate of condensation, the system is at equilibrium.

Vapor pressure of a liquid

the pressure exerted by the vapor at equilibrium

Boiling point

the temp at which the vapor pressure of the liquid becomes equal to the atmostpheric pressure.

What happens when you go to a mountain where the atmpospheric pressure is lower than 1 atm?

The boiling point lowers

What are the 2 Van der Waals subtypes?

Dipole-Dipole interactions- attractive forces between polar molecules.

London forces- as electrons are in continous motion, a nonpolar molecule could have and instantaneous dipole.(short-lived)

Characteristics of London forces

-Exist between all molecules.

-the only attractive force between nonpolar atoms or molecules.

-electrons are in constant motion

-the temporary dipole interacts with other temporary dipoles to cause attraction.

Hydrogen Bonding

-not a van der waals force

-type of dipole-dipole

-causes higher than expected b.p and m.p

Requirements: molecules have hydrogen directly bonded to O, N, or F 

Joule Thompson Effect

When a gas under pressure is allowed to escape into a lower pressure, cooling occurs

Critical temperature

the temp at which the substance will become a gas under any pressure.

Gases liquify under sufficient pressure if their temp is under the critical temp.

Kinetic molecular theory of gases

1.the atoms or molecules are in constant, random motion.

2.a gas is mostly empty space

3.all of the atoms and molec behave independently.

4.they collide with each other and the walls of container without losing energy. energy is transferred from one atom to another.

5. the avg kinetic energy increases or decreases in proportion to absolute temp.

Properties of gases and the kinetic molecular theory

-gases will expand to fill any available volume.

-gases have low density

-gases readily diffuse through each other.

-gases exert pressure on their containers.

-gases behave ideally at low pressures and high temperatures.

Solute

the substance present in the largest quantity.

-Clear, transparent, no visible particles

-may have color

-volumes of solute and solvent are not additive

-non electrolytes do not dissociate

-solute particles which are not uniformly distributed

-appears identical to solution form the naked eye.

-smaller than 1nm, have solution

-Larger than 1nm, have a precipitate

Tyndall Effect

-the ability of a colloidal suspension to scatter light.

- there is a haze

1. Polarity of solute and solvent(the more different they are, the lower the solubility.

2.Temperature

3.Usually has no effect unless pressure is on gas in a liquid, directly proportional to applied pressure.

What temperatures are gases most soluble in?

Low temperatures

-solubility decreases significantly at higher temperatures.

Moler per liter (molarity)

or

Equivalents per liter (eq/L) --emphasis on charge

Name the four colligative properties

1.Vapor pressure lowering

2.Boiling point elevation

3.freezing point depression

4.osmotic pressure

Vapor pressure lowering(colligative prop #1)

Describe

Raoult's law- when a nonvolatile solute is added to a solvent, vapor pressure of the solvent decreases in proportion ot the concentration of the solute.

-solute molecules serve as a barrier to the escape of solvent molecules resulting in a decrease in the vapor pressure.

Solute molecules interfere with the rate at which liquid water molecules associate to form the solid state.

-an equal conc of NaCl will affect the f.p. twice as much as glucose.(NaCl 2 particles, glucose 1)

Boiling point elevation (colligative prop #3)

If a solute is present, the increase in boiling temp is necessary to raise the vapor pressure to atmospheric pressure.

-an electrolyte will affect the boiling point to a greater degree than a nonelectrolyte of the same concentration.

the pressure that must be exerted to stop the flow of water across a selectively permeable membrane by osmosis.

Osmolarity

The molarity of particles in solution.

mol particle/L

have identical osmotic pressures and no osmotic pressure difference across the cell membrane.

Osmolarity inside the cell and outside are the same.

solute concentration of fluid higher than inside the cell causing water to flow into the surrounings  causing crenation(collapse)

water will move from area of higher conc to lower.

Cl- and HCO3-

Cl-acid/base balance, maintnance of osmotic pressure, and oxygen transport by hemoglobin.

HCO3-  Form in which most waste CO2 is carried out of the body.

-blood clotting factors

-antibodies

-albumins(carriers of nonpolar substances which cannot dissolve in water)

-Proteins are transported as a colloidal suspension

-molecules and atoms a reaction mixture are in constant random motion

-they frequently collide with each other

-some collisions, those with sufficient energ, will break bonds in molecules

-when bonds are broken, new bonds may be formed and products result

the absolute value for energy stored in a chemical system cannot be measured.

-the change in energy during these chemical changes can be measured.

endothermic reaction

represents heat energy

energy release= (-) exothermic

energy absorbed=(+) endothermic

states that the universe spontaneously tends toward increasing disorder or randomness.

high entropy- disordered

low entropy-well organized

occur without any external energy input.

-most are exothermic

-higher in entropy(more disorganized)

-usually endothermic

-products with lower entropy

a collision that produces product molecules.

-only effective collisions lead to chemical reaction.

an unstable state that the reaction proceeds from reactants to products.

-this cannot be isolated.

activation energy

-structure of the reacting species

-molecular shape and orientation

-concentration of reactants

-temp of reactants

-physical state of reactants

-presence of a catalyst

-oppositely charged species react faster(dissociated ions, very low activation energy.

-ions with same charge do not react

-large molecules may obstruct the reactive part of the molecule.

-only molecular collisions with correct orientation lead to product formation.

-rate will increase as concentration increases .

IE: more collisions per unit time and more reactant per unit volume.

The temperature of reactants(affect rate)

-rate increases as the temp increases

-increased kinetic energy, inc speed of particles, more collisions

What physical state does a reaction proceed fastest in?

Liquid>Gas>Solid

the synthesis of ammonia facilitated by a solid phase catalyst.

-diatomic gases bind to the surface

-bonds weakened

-newly formed NH3 leaves the solid surface

the rate of the forward process in a reversible reaction is exactly balanced by the rate of the reverse process.

Ex: sugar in H20, it may look like nothing more is dissolving, but actually some of sugar continues to be dissolved and at the same rate solid sugar molecules are being formed.

what is left out in the equilibrium constant expression?

the extent to which reactants have converted to products.

-addition of products or reactants does not affect the value of the equilibrium constant.

a base dissociates to form H⁺

an acid dissociates to form OH^-

an acid is a proton(H⁺) donor.

a base is a proton(H⁺) acceptor.

a substance possesing both acid and base properties.

water can act as an acid or base.

strength is a measure of degree of dissociation of an acid or base in solution, independant of concentration.

-acids and bases are classified as strong when the reaction with water is 100% complete. 

Acids with the greatest proton donating capability (strongest acids) have the weakest conjugate bases.

Good proton acceptors(strong bases) have weak conjugate acids.

dissociation of acids and bases is called ionization.

-water goes through autoionization (self-ionization)

-water is a weak electrolyte and a poor conductor of electricity.

because of their exothermic reaction with water present on and in the skin.

-bases react with proteins, affecting the skin and eyes.

this refers to the product of hydronium and hydroxide ion concentration in pure water.

-the ion product is a temperature dependant quantity.

-It equals 1.0 x 10^-14 at 25 C

pH scale

gauges the hydronium ion concentration and reflects degree of acidity or basicity of a soln.

-if add an acid (H₃O), (OH decreases)

-if add a base (OH), (H₃O decreases)

the reaction of an acid with a base to produce a salt and water.

-when writing a net, balanced equation remove spectator ions(dont change)

-the analytical techniqu to determine the concentration of an acid or base is titration

donates or accepts more than one H⁺ ion per each formucla unit.

Ex: H₂SO₄

a solution which resists large changes in pH when either acids or bases are added.

- they establish equilibrium between a weak acid and its conj base or a weak base and its conj acid.

OH reacts with H₃O to produce water, acid dissociates to replace H₃O.

therefore shift to right occurs.

the amount of strong acid or strong base that a buffer can neutralize without significantly changing the pH.

-loss of electrons

-loss of hydrogen atoms

-gain of oxygen atoms

-gain of electrons

-gain of hydrogen

-loss of oxygen

-is reduced

-gains electrons

-causes oxidation

-is oxidized

-loses electrons

 -causes reduction

Corrosion, combustion of fossil fuels, and bleaching.

Respiration, Metabolism

electrochemical cell that converts stored chemical energy into electrical energy.

Ex:batteries

use electrical energy to cause nonspontaneous oxidation-reduction reactions to occur.

-they are the reverse of voltaic cells.

Ex: rechargable battery

-2 protons, 2neutrons

-same as He nucleus

-slow, stopped by small barriers(travels 10% of speed of light)

-fast moving electron(travels at about 90% of speed of light)

-emitted from the nucleus as a neutron converted to a proton.

pure energy (electromagnetic radiation)

-highly energetic

most penetrating

produces a trail of ions throughout the material that it penetrates.

alpha<beta<gammarays

-same mass as beta particle, but carries positive charge.

-produced by the conversion of a proton to a neutron in the nucleus of the isotope.

-unlike beta, it has the same mass number, but the atomic number has decreased by one.

the energy that holds the protons,neutrons, and other particles together in the nucleus.

-in radioisotopes binding energy is large

when isotopes decay(become more stable) binding energy is released.

is the time required for one half of a given quantity of a substance to undergo change.

-isotopes with short half-lives decay rapidly;they are very unstable.

radiocarbon dating

the ratio of carbon-14 to carbon-12 stays constant during its lifetime.

-when living system dies, it quits taking in the carbon-14

How old can the artifact be to be able to use carbon-14 dating?

occurs when a heavy nuclear particle is split into smaller nuclei by a smaller nuclear particle.

-produces large amts of energy

-is self perpetuating

-can be used to generate steam

combination of two small nuclei to form a larger nucleus.

-large amts of energy released

-Ex: sun

-no plant exists

Breeder reactor

fission reactor that manufactures its own fuel

-nuclear energy(nuclear reactor)--heat energy(steam)--mechanical energy(turbine)--electrical energy(electricity)

Distance from radio active source

radiation intensity varies inversely with the square of the distance from the source.

-doubling the distance from source decreases the intensity by a factor of 4.