Chemistry Exam 3

Thermochemistry

The study of the relationship between chemistry and energy

energy

the capacity to do work

work

the action of force through distance

Two types of energy

potential energy and Kinetic energy

Chemical potential energy

energy associated with chemical composition; position of electrons and protons

potential energy

energy associated with position

kinetic energy

energy associated with motion

thermal energy

the energy associated with temperature

The law of conservation of energy

energy is neither created nor destroyed. systems with high potential energy tend to get to positions of lower potential energy. A release of energy to the surroundings.

system

the portion of the universe under investigation

Surroundings

everything else

SI unit for energy

joule

calorie

the energy required to raise the temp of one gram of water by 1 degree Celsius

thermodynamics

the study of energy and its interconversions

first law of thermodynamics

the total energy of the universe is constant

internal energy (E)

only depends on the state, not how you got there

state function

the sum of the kinetic and potential energy in a system

heat

the transfer of thermal energy between the system and the surroundings

thermal equilibrium

occurs when temperature of a system and the surroundings are the same (there is no heat transfer)

C (Heat Capacity)

quantity of heat required to change temperature of a substance by 1 degree Celsius

Extensive property

depends on the amount of matter

the higher the heat capacity

the larger the amount of heat required to raise the temperature

specific heat capacity

quantity of heat required to raise the temperature of 1 gram by 1-degree Celcius

intensive property

depends on the type of matter not the amount

molar heat capacity

the amount of heat required to raise one mol by 1-degree Celcius

calorimetry

the thermal exchanged between the reaction and the surroundings is measured by a temperature change

electric field

a region of space where an electrically charged particle experiences a force

magnetic field

a region of space where a magnetic particle experiences a force

the electric field and magnetic field are ________ to each other

perpendicular

light moves _________ sound moves _________

faster;slower

amplitude

the height of a crest of the depth of a trough > determines intensity of light

wavelength

the distance between two adjacent crests/troughs > determines color of light

frequency

The number of cycles that pass through a stationary point in a given amount of time.

white light

the light produced by the sun > gives us the spectrum of colors

As wavelength increases

frequency decreases

electromagnetic spectrum

includes all known wavelengths of the electromagnetic radiation

the higher the frequency

the greater the energy

constructive interference

if two waves have = amplitude and are in-phase, a wave with twice the amplitude will result

Destructive interference

if two waves have = amplitude and are out of phase, they cancel each other out.

photoelectric effect

it was noticed that when light shines on a metal the metal emits electrons-but the amount of electrons emitted depends on the frequency of light not the intensity

Threshold frequency

electrons are only emitted once a certain frequency is reached

photon

packet of energy

Threshold Frequency Condition

once the threshold frequency is reached the energy of the electron is equal to its binding energy, so the electron is released. The extra energy is passed on to the electron as kinetic energy

Atomic Spectroscopy

The study of electromagnetic radiation absorbed and emitted by electrons

When atoms absorb energy they can reemit that energy as light. Different elements emit different colors of light and often multiples colors this is called

emission spectrum

Elements can be identified using the

emission spectrum

electrons are only found in________ never _________

specific orbitals; between

The further apart the states of transition

the higher the energy produced

the faster an electron is moving

the higher the kinetic energy

The higher the energy

the shorter the wavelength

The DeBrogile Relation

you can determine that wavelength of an electron if you know its mass and velocity

an electron may be observed as a _______ or a _________ but never both at the same time

wave or a particle

n=

the principal quantum number

l=

angular momentum quantum number

ml=

magnetic quantum number

ms=

spin quantum number

The principal quantum number determines

overall size and energy of an orbital

the further from the nucleus

the higher the energy

principal level

orbitals with the same “n” value are in the same principal level

sublevel/ subshell

orbitals with the same “n” and “l” values