Test 3 Formulas, units and symbols Flashcards by Roger Kline

Formula: KE avg =

KEavg = 1/2m(Urms)^2
m = mass of the object in kg
Urms = root-mean-square-speed of a gas
KEavg = average Kinetic energy

How well did you know this?

Not at all

Perfectly

Formula: Urms =

Urms = sqrt((3RT)/M)
Urms = root-mean-square-speed of a gas
sqrt = square root
R = Universal gas constant
T = Temperature of gas, Kelvin
M = molar mass of the gas, ( kg/mol )

How well did you know this?

Not at all

Perfectly

Units: Urms

m/s, meters per second

How well did you know this?

Not at all

Perfectly

Units: R

8.314 J / mol*K

How well did you know this?

Not at all

Perfectly

Kinetic molecular theory states

at any given temperature, a population of gas particles has the same average kinetic energy

How well did you know this?

Not at all

Perfectly

Root-Mean-Square_Speed is

The speed of a gas molecule possessing the average kinetic energy

How well did you know this?

Not at all

Perfectly

Effusion is the

process by which gas molecules escape through a small hole

How well did you know this?

Not at all

Perfectly

Formula: Graham’s Law

Rate1 / Rate2 = sqrt(M2 / M1)
Rate = Urms
M = molar mass of the gas, ( kg/mol )

How well did you know this?

Not at all

Perfectly

Formula: First law of thermodynamics

dEsys = -dEsurr
dE = Change of energy

How well did you know this?

Not at all

Perfectly

Formula: dEsys =

dEsys = q + w
q = dHeat
w = work

How well did you know this?

Not at all

Perfectly

Formula: w =

w = -PdV
w = work, under conditions of constant pressure
P = pressure
dV = change in volume

How well did you know this?

Not at all

Perfectly

-qlost = qgained, is used in

Calorimetry

How well did you know this?

Not at all

Perfectly

Calorimetry is the

science associated with determining the heat transfer during chemical reactions or physical changes

How well did you know this?

Not at all

Perfectly

Formula: Heat capacity =

qcal = C*dT
qcal = J
C = Heat capacity, J / degC
dT = Change in temperature

How well did you know this?

Not at all

Perfectly

Formula: Molar heat capacity =

qmol = n*Cp*dT
gmol = J
n = number of moles
Cp = molar heat capacity, J / mol * degC
dT = Change in temperature

How well did you know this?

Not at all

Perfectly

Formula: specific heat capacity =

qgram = m*S*dT
qgram = J
S = specific heat capacity, J / g*degC
m = mass in grams
dT = Change in temperature

How well did you know this?

Not at all

Perfectly

Formula: dH*rxn =

dH*rxn = Sum (dH*fproducts) - Sum (dH*freactants)
dH*rxn = Standard enthalpy change
dH*f = Standard enthalpy of formation

How well did you know this?

Not at all

Perfectly

Heat capacity (C)is

the amount of energy requried to raise the temperature of an entire object by 1 degC

How well did you know this?

Not at all

Perfectly

Molar heat capacity (Cp)

the amount of energy required to raise the temperature of 1 mol of a substance by 1 degC at constant pressure

Specific heat capacity (s) is

the amount of energy required to raise the temperature of 1 gram of a substance by 1 degC at constant pressure

Formula: qp =

qp = dH
qp = heat at constant pressure
dH = change of enthalpy

Unit: dE =

change of energy

Unit: dH =

change of enthalpy

Endothermic reaction

heat is absorbed, and the system has a positive symbol

Exothermic reaction

heat is released, and the system has a negative symbol

Open system

Mass: exchanges mass with surroundings Heat: exhanges heat with surroundings

Closed system

Mass: Does not exchange mass with surroundings Heat: Exchanges heat with surroundings

Isolated system

Mass: Does not exhange mass with surroundings Heat: Does not exchange heat with surroundings

Standard heat of formations is also known as

The standard enthalpy of formation

Standard state rules for a gas

the standard state for a gas is the pure gas at a pressure of exactly 1 atm

standard state rules for a liquid or solid

the standard state for a liquid or solid is the pure substance in its most stable form at a pressure of 1 atm and at the temperature of interest

standard state rules for a substance in solution

the standard state for a substance in solution is a concentration of exactly 1M

Standard enthalpy change, symbol and rule

dH*, the change in enthalpy for a process when all reactants and products are in their standard states. The degree sign indicates standard states

standard enthalpy of formation, symbol and rules

dH*f, pure compound: the change in enthalpy when one mole of the compound forms from its constituent elements in their standard states Pure element in its standard state: dH*f = 0

Written summary of the dH*rxn = formula

to caldulate dH*rxn, subtract the enthalpies of formation of the reactats multiplied by their stoichiometric coefficients from the enthalpies of formation of the products multiplied by their stoichiometric coefficients

Hess's law

if a chamical equation can be expressed as the sum of a series of steps, then dHrxn for the overall equation is the sum of the heats of reactions for each step

Relationships involving dHrxn (3)

1. If a chemical equation is multiplied by some factor, then dHrxn is also multiplied by the same factor 2. if a chemical equation is reversed, then dHrxn changes sign 3. if a chamical equation can be expressed as the sum of a series of steps, then dHrxn for the overall equation is the sum of the heats of reactions for each step

Units and symbol: frequency

Hz = 1/s | v

units and symbol: wavelength

meters | lamduh, (upside down y)

Wavelength definition

the distance between two analogous points on successive waves

amplitude definition

vertical measurement from the midline of a wave to the top of a peak or bottom of a trough

frequency definition

is equal to the number of complete wave cycles that pass through a point in one second

The greater the number the frequency the ______ the energy

greater

the greater the number of the wavelength the ____ the energy

lower

Frequency and amplitude are directly proportional to the _____

energy

frequency and wavelength are ______ proportional to the energy

inversly

order of waves the the electromagnetic spectrum by low energy to high energy

radio, microwave, infrared, visible light, ultraviolet, x-ray, gamma ray