question

thermodynamics

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study of energy and its transformations

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thermochemistry

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branch of thermodynamics that deals with heat in chemical and physical changes

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system

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part of the universe that is being focused on

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surroundings

answer

everything (in reason) that is not the system

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internal energy E

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sum of all kinetic and potential energy of each particle in a system

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DE =

answer

Efinal - Einitial
Eproducts - Ereactants
q + w

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a change in energy of the system must be accompanied by

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an equal and opposite change in energy of the surroundings

question

releasing energy in a transfer to the surroundings

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Efinal < Einitial so DE<0

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absorbing energy in a transfer from the surroundings

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Efinal > Einitial so DE>0

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q symbolizes

answer

heat

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heat -

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energy transferred as a result of the difference in temperature between the system and the surroundings

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w represents

answer

work

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work -

answer

energy transferred when an object is moved by a force

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energy transferred into the system is

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positive because the system ends up with more energy
DE is positive

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energy transferred out of the system is

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negative because the system ends up with less energy
DE is negative

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the law of energy conservation

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the 1st law of thermodynamics
the total energy of the universe is constant

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joule (J)

answer

SI unit for energy

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1 J =

answer

1 kg*m^2/s^2

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calorie (cal)

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quantity of energy needed to raise the temperature of 1 gram of water by 1 *C

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1 cal = _____ J

answer

4.184 J

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1 J = ___ cal

answer

0.2390 cal

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the internal energy of a system is called a

answer

state function

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a state function is dependent on

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the current state of the system, not on the path the system takes to reach that state

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DE depends on

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the difference between the final and initial states, not on how the change takes place

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pressure-volume work (PV work)

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mechanical work done when the volume of the system changes in the presence of eternal pressure

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w =

answer

-P DV

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H stands for

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enthalpy

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enthalpy-

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internal energy plus the product of the pressure and volume

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H =

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E + PV

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DH =

answer

DE + P DV

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the change in enthalpy equals

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the heat absorbed or released at constant pressure

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exothermic process

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releases heat and results in the decrease in the enthalpy of the system

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endothermic process

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absorbs heat and results in an increase in the enthalpy of the system

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q =

answer

c * mass * DT

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heat capacity -

answer

quantity of heat required to change its temperature by 1 K

question

heat capacity =

answer

q / DT

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specific heat capacity -

answer

quantity of heat required to change its temperature of 1 gram of the object by 1 K

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c represents

answer

specific heat capacity

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c =

answer

q / (mass * DT)

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molar heat capacity -

answer

quantity of heat required to change its temperature of 1 mole of the substance by 1 K

question

C represents

answer

molar heat capacity

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coffee cup calorimeter

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device that measures the heat transferred at constant pressure

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bomb calorimeter

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device measures the heat released at constant volume

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thermochemical equation

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balanced equation that includes the enthalpy change of the reaction

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Hess' Law

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the enthalpy change of an overall process is the sum of the enthalpy changes of its individual steps

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DHoverall =

answer

DH1 + DH2 + DH3...

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standard state for a gas

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at 1 atm and ideal behavior

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standard state for a for a substance in aqueous solution

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1 M concentration

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standard state for a for a pure substance (element or compound)

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the most stable form of the substance at 1 atm and 25*C (298K)

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in a formation equation

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1 mol of a compound forms from its elements

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standard enthalpy of formation

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enthalpy change for the formation equation when all the substances are in their standard states

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the standard enthalpy of reaction is

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the sum of the standard enthalpy of formation of the products minus the sum of the standard enthalpy of formation of the reactants

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examples of fossil fuels

answer

petroleum, coal and natural gas

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Kinetic Energy

answer

The energy associated with motion

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Thermal Energy

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Motion of atoms, molecules or ions at the submicroscopic level

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Mechanical Energy

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Motion of a macroscopic objects like a moving basketball or airplane

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Electrical Energy

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Movement of electrons through a conductor

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Acoustic Energy

answer

The compression and expansion of molecules in the transmission of sound.

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Potential Energy

answer

The energy associated with an objects position

question

types of kinetic energy

answer

Acoustic Energy
Electrical Energy
Mechanical Energy
Thermal Energy

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Gravitational Energy

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Energy possessed by a ball held above the floor or by water at the top of a water fall

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Chemical Energy

answer

Energy stored in fuels or in chemical bonds

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Electrostatic Energy

answer

The energy associated with the separation of two electrical charges.

question

Types of Potential energy

answer

Gravitational Energy
Chemical Energy
Electrostatic Energy

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Law of Conservation of Energy

answer

Energy can neither be created nor destroyed

question

w stands for

answer

Energy transferred as work to or from the system

question

Internal Energy

answer

The formal name for the quantity E.
Internal energy in a chemical system is the sum of PE and KE of the atoms, molecules or ions

question

enthalpy is

answer

equal to the amount of energy transferred as heat at a constant pressure.

question

If ?H is negative,

answer

energy is transferred as heat from the system to the surroundings. Exothermic.

question

If ?H is positive,

answer

energy is transferred as heat from the surroundings to the system. Endothermic.

question

The temperature of an object is a measure of

answer

its ability to transfer energy as heat.

question

The higher the temperature,

answer

the greater the thermal energy of the materials atoms, ions or molecules

question

Thermal Equilibrium

answer

When two objects which were once at different temperatures, reach the same temperature

question

Energy transfer as heat will occur spontanesosly from _____ to ______

answer

the higher temperature material to the lower temperature material

question

Calorimetry

answer

The method by which the energy evolved or required as heat in a chemical of physical process is measured.

question

Change of State

answer

conversion of a substance from one physical state to another, i.e. from a liquid to a solid or from a liquid to a gas

question

Heat of Fusion

answer

The energy transferred as heat that is required to convert a substance from a solid to a liquid

question

Heat of Vaporization

answer

The energy transferred as heat that is required to convert a substance from a liquid to a gas

question

The superscript o indicates that

answer

the reaction has been run at standard conditions.

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Enthalpy changes are specific to

answer

the reaction being carried out. State of the product produced, is important as are the amounts of products and reactants.

question

The enthalpy change depends on the

answer

number of moles of reaction. That is how many times the as written reaction is carried out.

question

Electromagnetic Radiation

answer

Characterized by wavelength and frequency and includes light, microwaves, television and radio signals x-rays, and other forms of radiation

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wavelength

answer

ambda, ?, the distance between successive crest or high points of a wave. The distance is usually measured in m or nm

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frequency

answer

nu, ?, refers to the number of waves that pass a given point in some unit of time, usually per second. The unit of frequency, written as s-1 or 1/s is called hertz.

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Clight =

answer

Clight = 2.99792458 x 108m/s

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Magnetic vector moves _______ to that of the electric vector

answer

perpendicular

question

Nodes:

answer

where the wave changes from positive to negative

question

Plank Assumed

answer

that the EMR emitted was caused by vibrating atoms called oscilators. And if each oscilator had a frequency, and the emitted radiation had a certain energy, the following eqn could be written.

question

Plank’s Constant:

answer

h = 6.6260693 x 10 -34 J*s

question

E=

answer

h * wavelength

question

Photoelectric Effect

answer

electrons are ejected when light strikes the surface of a metal.

question

The energy of each photon is proportional to

answer

the frequency of the radiation as defined by Planck’s eqn.

question

Einstein

answer

Photoelectric Effect

question

Line Emission Spectrum

answer

The spectrum obtained from passing a beam of light from the excited sample through a prism.

question

Balmer Equation

answer

1/ lambda = R (1/22 - 1/n22), where n is an integer and > 2

question

Rydberg Constant

answer

R = 1.0974 x 107 m-1

question

Balmer series.

answer

The 4 visible lines in the spectrum of hydrogen

question

Bohr derived an equation for

answer

the energy possessed by the single electron in the nth orbit of the H atom

question

Bohr Equation

answer

En = - Rhc / n2

question

n defines the

answer

energies of the allowed orbits in the H atom

question

deBroglie

answer

Proposed that matter which was normally considered a particle, could also exhibit wave properties. Previously for light in the photoelectric effect.

question

Bohr Model:

answer

That both the energy and the location for the electron in the hydrogen atom can be described accurately

question

Heisenberg:

answer

Determined that for an object such as an electron in an atom, it is impossible to determine accurately both its position and its energy.

question

Heisenberg Uncertainty Principle:

answer

any attempt to determine accurately either the location or the energy will leave the other uncertain.

question

Schrodinger

answer

Developed quantum mechanics or wave mechanics. Uses mathematical eqns of wave motion to generate wave functions which are used to describe a electrons in the atom.

question

the principle quantum number

answer

n

question

The value of n, is

answer

the primary factor in determining the energy and size of an orbital.

question

For any given atom, the greater the value of n,

answer

the greater the size of the orbital.

question

Orbitals are grouped into _____ .

answer

subshells

question

each subshell is characterized by a different value of ____

answer

I

question

I defines the characteristic

answer

shapes of the orbitals.

question

mf is related to the

answer

orientation in space of the orbital within a subshell.

question

Paramagnetic

answer

Elements or compounds that have unpaired spins and are attracted to magnets.

question

Diamagnetic

answer

Substances in which all the electrons are paired (with 2 electrons in each pair, having opposite spins) experience a slight repulsion when subjected to a magnet

question

electron spin quantum number

answer

ms

question

frequency

answer

the number of cycles a wave undergoes per second

question

electromagnetic radiation consists of

answer

energy propagated by electric and magnetic fields that increase and decrease in intensity as they move through space

question

visible light, x rays and microwaves are examples of

answer

electromagnetic radiation

question

wavelength

answer

the distance between any point on a wave and the corresponding point on the next crest of the wave
the distance the wave travels in one cycle

question

speed of light (c) =

answer

wavelength * frequency

question

amplitude

answer

the height of the crest of wave or the depth of the trough

question

the amplitude of a wave is related to the

answer

intensity of the radiation

question

types of waves by increasing wavelegth

answer

gamma
x-ray
ultraviolet
visible
infrared
microwave
radio

question

types of waves by increasing frequency

answer

radio
microwave
infrared
visible
ultraviolet
x-ray
gamma

question

visible light goes from

answer

400 nm (violet) to 750nm (red)

question

refraction

answer

when a light wave passes through on medium and into another and the speed of the wave changes, making the wave bend in shape

question

dispersion

answer

white light separates into its component colors when it passes through a prism

question

diffraction

answer

when a wave strikes against an object and it bends around it

question

blackbody radiation

answer

when a solid object is heated to about 1000 K and it begins to emit visible light

question

the quantum theory was created by

answer

Planck

question

the photon theory was created by

answer

Einstein

question

wavelength and frequency have a _____ relationship

answer

reciprocal

question

line spectrum

answer

a series of fine lines at specific frequencies separated by black spaces

question

Rydberg equation predicts

answer

the position and wavelength of any line in a given series

question

Rydberg equation

answer

(1 / wavelength) = R ((1 / n1^2) - (1 / n2^2))

question

the Hydrogen model atom was created by

answer

Bohr

question

Postulates of Bohr's Hydrogen Atom Model

answer

the H atom has only certain energy levels
the atom does not radiate energy while in one of its stationary states
the atoms changes to another stationary state only when absorbing or emitting a photon

question

ground state

answer

when the electron is in the first orbit, is closest to the nucleus and the H atom is in the lowest (first) energy level

question

excited state

answer

if the electron is in any orbit other than the first orbit

question

an atomic spectrum (is/ is not) continuous because

answer

is not; the atom's energy is not continuous, but rather has only certain states

question

an atom changes energy by

answer

absorbing or emitting a photon of specific energy

question

Bohr's Equation

answer

DE = Efinal - Einitial = -2.18x10^-18 J ((1/ nfinal^2) - (1/ninitial^2))

question

emission spectrum is produced when

answer

atoms in an excited state emit photons characteristics of an element as they return to lower energy states

question

absorption spectrum is produced when

answer

atoms absorb photons of certain wavelengths and become excited from lower to higher energy states

question

a spectrometer is used to measure

answer

the concentration of a substance in a solution

question

absorbance -

answer

the amount of light of a given wavelength absorbed by a substance

question

absorbance is proportional to

answer

the amount of molecules

question

Bohr proposed that

answer

electrons move in a fixed orbit

question

atomic orbit

answer

mathematical description of the electron's matter-wave in three dimensions

question

n represents

answer

the principle quantum number

question

the principle quantum number indicates

answer

the relative size of the orbital and therefore the relative distance from the nucleus

question

l represents

answer

angular momentum quantum number

question

angular momentum quantum number indicates

answer

the relative shape of the orbital

question

ml indicates

answer

the magnetic quantum number

question

the magnetic quantum number describes the

answer

3D orientation of the orbital

question

the atoms levels are given by the

answer

n value

question

the atoms levels are divided into sublevels that are given by the

answer

l value

question

l = 0 is what sublevel

answer

s

question

l = 1 is what sublevel

answer

p

question

l = 2 is what sublevel

answer

d

question

l = 3 is what sublevel

answer

f

question

No more than ____ electrons can be in an atomic orbital.

answer

2

question

Pauli Exclusion Principle

answer

No two electrons can have the same set of quantum numbers.

question

Aufbau Principle

answer

The procedure in which electrons are assigned to orbitals.

question

Atomic Size is related to

answer

the distance between atoms in a sample of the element

question

For the main group elements, atomic size generally

answer

Increases going down a group due to the larger number of outer (valence electrons)
Decreases going across a period due to the larger effective nuclear charge

question

Ionization Energy

answer

The energy required to remove an electron from an atom in the gas phase.

question

Ionization energies general

answer

general increase across a period due to the increase in effective nuclear charge
decrease down a group due to the increase in size

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