# Final Exam - Semester 2

## 150 terms

### chemical reactions

substances are converted into new substances by the rearranging of their atoms into new combinations

### chemical equations

description of atomic rearrangement in chemical reactions

### Mole to Mole problem

moles of known --> moles of unknown

### Mole to Mass

mole of known --> mole unknown --> mass of unknown

### Mass to Mole

mass known --> mole known --> mole unknown

### Mass to Mass

mass known --> mole known --> mole unknown --> mass unknown

### limiting reactant

substance in reaction that limits the amount of product made

### excess reactant

substance you have left over

### percent yield formula

% yield = (actual yield / theoretical yield) * 100%

### kinetic theory

assumes all particles in a substance are in constant motion
-state of matter determined by amount of motion and spacing between the particles
-Temperature = average of kinetic energy in substance

### solid particles are..

closely packed; vibrate slightly

### liquid particles are...

further apart; slip and slide around

### gases

very apart; zipping around

### ideal gases

low density
high compressibility
high expansion

### diffusion

movement of particles from areas of high to low concentration

### effusion

diffusion of a gas out of its container

### Graham's law of effusion

Rate A / Rate B = square root of Mb / square root of Ma

### gas pressure

force per unit area; force exerted by the collision of the gas particles against the sides of the container

### Unites of pressure

1 atm = 760 mm Hg = 760 torr = 14.7 psi =101.3 KPa

### Dalton's law of partial pressures

total pressure of a mix of gases is equal to the sum of the partial pressures of each gas

### intermolecular forces

forces between 2 molecules

### London dispersion forces

(weakest)
-collision of 2 molecules which induces a dipole

### Dipole - Dipole

2 polar molecules are attracted to each other

### Hydrogen bonding

same as dipole-dipole
-one atom is hydrogen

able to flow

### viscosity

resistance to flow

### surface tenstion

attraction of particles towards center

### capillarity

tendency for a liquid to stick to the sides of its container

### cystallive solids

repeating geometric patterns

### cubic (solid)

-equal sides
-90 degree angles

### tetragonal (solid)

-2 equal sides
-90 degree angles

### orthorhombic (solid)

-no equal sides
-90 degree angles (opposite sides are equal)

### rhombohedral (solid)

-equal sides
-equal angles, none of which are 90 degrees

### freezing

removal of energy from liquid causes particles to SLOW DOWN and get CLOSER

### melting

increase in energy causes particles to MOVE FASTER and SPREAD APART

### molar heat of fusion

amount energy needed to convert 1 mol from solid to liquid at its melting/freezing point

### vaporization

transition from liquid to gas

### boiling

vapor pressure of liquid must exceed atomspheric pressure

### evaporation

molecules ON SURFACE of liquid gain enough energy to BREAK OFF from the rest

### molar heat of vaporization

amount energy needed to convert 1 mol of any liquid to a gas at its boiling temperature

### condensation

transition from gas to liquid

### sublimation

solid to gas (without liquid phase)

### deposition

gas to solid (without liquid phase)

### triple point

temperature & pressure at while all 3 states are at equilibrium

### critical point

critical tempertuare and pressure of a substance

### critical temperature

temp beyond which no amount of pressure can force a gas back into a liquid

### critical pressure

when at critical temp, its minimum amount of pressured needed to make it a liquid

### Ideal vs real gases

1. do not attract or repel particles
2. elastic collision
3. no volume of own
4. constant random motion
5. same average kinetic energy at same temperature

PiVi = PfVf

ViTi = VfTf

Pi/Ti = Pf/Tf

### Combined gas law

PiVi/Ti = PfVf/Tf

### absolute zero

0 Kelvin = -273 degrees Celsius

two equivalent volumes of different gases at the same temp and pressure will contain same number of particles

### molar volume

amount space that 1 mol of any gas occupies at STP

22.4 L

### ideal gas law

-moles to volume conversion when not as STP
-PV=nRT

### Volume to Volume

volume A --> volume B

### Volume to Mass

Volume of A --> moles of A --> moles of B --> mass of B

### solutions

homogeneous mixtures; two or more substances in one distinct phase

### solute

substance that is dissolved

### solvent

substance doing the dissolving

### alloy

solution of 2 or more metals

### miscibility

ability of 2 liquids to mix

can mix

can't mix

### "like dissolves like"

polar subsatnces dissolve other polar substance, etc.

### molar heat of solution

when some substances dissolve, they gain (endothermic) or lose (exothermic) heat

### Factors affecting dissolution (rate)

1. Surface area - increase of SA cuases increase of dissolution
2. stirring/agitation - mechanically increasing kinetic energy, increasing contact
3. temperature - increased temp = increased kinetic energy

### saturated

MAXIMUM of solute dissolved

### unsaturated

under MINIMUM solute dissolved

### supersaturated

MORE THAN MAXIMUM solute dissolved

Si/Pi = Sf/Pf

### percent by mass

-ratio of mass of solute to mass of solution
% mass = mass solute / mass solution

### percent by volume

-ratio of volume of solute to volume to solution
% volume = volume solute / volume solution

### Molarity (M)

M = n solute / volume solution

MiVi=MfVf

### Molality (m)

m = n solute / mass (kg) solvent

### osmotic pressure

force of water movement

### osmosis

diffusion of water across a semi-permeable membrane

### vapor pressure depression

force of liquid trying to become a gas

### boiling point elevation

when solute is added to solvent, the boiling point of solvent increases

### colligative properties formula

Delta Tb = i m Kb

### freezing point depression

when solute is added to solvent, frezzing point of solvent decreases

### characteristics of solutions (6)

1. particles < 1nm
2. example: salt water
3. homogeneous
4. doesn't settle upon standing
5. cannot be filtered
6. transmits light

### characteristics of colloids (6)

1. particles: 1-1000nm
2. examples: milk, gems, jello, blood
3. homogeneous or heterogeneous
4. can settle (not consistent)
5. can be filtered, not all
6. tyndall effect: scatters light

### characteristics of suspensions (6)

1. particles > 1000nm
2. example: muddy water
3. heterogeneous
4. settles at bottom upon standing
5. can be filtered
6. opaque

### law of conservation of energy

energy can neither be created nor destroyed (measured in joules)

### specific heat capacity (Cp)

amount energy needed to raise 1 gram of a substance to 1 degree celsius

### specific heat formula

Cp = q/(m*delta T)

1000 calorie

### thermochemical equations

equations that include amount of energy absorbed or released

### exothermic

energy is on PRODUCT side

### endothermic

energy is on REACTANT side

### enthalpy (delta H)

amount energy transferred in reaction

endothermic

exothermic

### Hess' law

can add up partil reactions to get enthalpy of full reaction

### Entropy (delta S)

-measure of amount of disorder

### increase = (+ delta S)

usually spontaneous

### Predicting entropy (increase)

1. converting substance from liquid to gas
2. dissolving solid/liquid into solution
3. increasing temp
4. if products have more gas particles than reactants in reaction

### Predicting entropy (decrease)

1. when gas dissolves in a solution

### decrease = (- delta S)

usually non-spontaneous

### Gibb's free energy (delta G)

-determines whether or not reaction is spontaneous
-delta G = delta H - T * delta S

spontaneous

non-spontaneous

### reaction rates formula

average rate = delat concentration / time

### collision theory (3)

1. reactants must collide in PROPER ORIENTATION
2. reactants must collide with ENOUGH FORCE to form activated complex
3. activated complex sometimes needs an ACTIVATION ENERGY to make reactants react

### activated complex

temporary unstable arrangement of atoms that break aprt to form products

### exothermic reaction

Graph:
starts high, boosts up little, falls down, levels out down low

### endothermic reaction

Graph:
starts low, goes up, falls down little, levels out up high

### Reaction rate factors (5)

1. nature of reactants
2. temp
3. surface area
4. catalyst
5. concentration

Rate = k[A]^1

1

### reaction order for complex reactions

rate = k[A]^x * [B]^y

### intermediates

substances that are formed over the course of the reaction that are consumed later in the elementary steps (can be cancelled out)

### complex reactions

having two or more elementary steps

### rate determing steps

step that determines overall rate (slowest step)

### reversible reactions

reactions in which occur in opposite directions

### equilibrium

state in which 2 opposing actions occur at same RATE

### law of equilibrium

at given temp, a chemical system will reach a state which the ratio of the concentration of products to reactants is a constant value (Keq)

### Keq formula

Keq = [products] / [reactants]

### if Keq > 1 then...

products outnumber reactants at equilibrium

### if Keq < 1 then...

reactants outnumber prodcuts at equilibrium

### Le Chatlier principle

when an equilirbium system is disrupted, it will shift to produce a new equilibrium

### "up, up, and away"

INCREASE in concentration causes a shift AWAY from side of equation that increased

### "down and towards"

DECREASE in concentration causes a shift TOWARDS side of equation that decreased

### Volume stressor (only gases)

INCREASE in volume favors side with MORE gas particles

### Pressure stressor (only gases)

INCREASE in pressure favors side with FEWER gas particles

### Temperature stressor (for exo- and endothermic)

write in energy to equation and test like concentration

NO precipitant

precipitant

### binary acids

made from HYDROGEN and one other ELEMENT

### oxyacids

made from HYDROGEN, OXYGEN, and one other ELEMENT

### arrhenius acids

substances that increase the concentration of H+ in solution

### arrhenius bases

substances that increase the concentration of OH- in a solution

proton donor

proton acceptor

### anhydrides

"without water"
substance that becomes an acid/base when water is added

### lewis acids

electron acceptors

electron donors

stronger acid

weaker acids

### amphoteric

substances that act as both acid and base

1.0 * 10^-14 M^2

acidic

basic

### titration

controlled edition of an acid or base of known concentration to a base/acid of unknown conentration to determind the unknown

### equivalence point

amount of acid and base in titration are equal (moles)

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