Flashcards in Test 3 Formulas, units and symbols Deck (47):

1

## 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

2

## 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 )

3

## Units: Urms

### m/s, meters per second

4

## Units: R

### 8.314 J / mol*K

5

## Kinetic molecular theory states

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

6

## Root-Mean-Square_Speed is

### The speed of a gas molecule possessing the average kinetic energy

7

## Effusion is the

### process by which gas molecules escape through a small hole

8

## Formula: Graham's Law

###
Rate1 / Rate2 = sqrt(M2 / M1)

Rate = Urms

M = molar mass of the gas, ( kg/mol )

9

## Formula: First law of thermodynamics

###
dEsys = -dEsurr

dE = Change of energy

10

## Formula: dEsys =

###
dEsys = q + w

q = dHeat

w = work

11

## Formula: w =

###
w = -PdV

w = work, under conditions of constant pressure

P = pressure

dV = change in volume

12

## -qlost = qgained, is used in

### Calorimetry

13

## Calorimetry is the

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

14

## Formula: Heat capacity =

###
qcal = C*dT

qcal = J

C = Heat capacity, J / degC

dT = Change in temperature

15

## 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

16

## 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

17

## Formula: dH*rxn =

###
dH*rxn = Sum (dH*fproducts) - Sum (dH*freactants)

dH*rxn = Standard enthalpy change

dH*f = Standard enthalpy of formation

18

## Heat capacity (C)is

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

19

## 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

20

## 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

21

## Formula: qp =

###
qp = dH

qp = heat at constant pressure

dH = change of enthalpy

22

## Unit: dE =

### change of energy

23

## Unit: dH =

### change of enthalpy

24

## Endothermic reaction

### heat is absorbed, and the system has a positive symbol

25

## Exothermic reaction

### heat is released, and the system has a negative symbol

26

## Open system

###
Mass: exchanges mass with surroundings

Heat: exhanges heat with surroundings

27

## Closed system

###
Mass: Does not exchange mass with surroundings

Heat: Exchanges heat with surroundings

28

## Isolated system

###
Mass: Does not exhange mass with surroundings

Heat: Does not exchange heat with surroundings

29

## Standard heat of formations is also known as

### The standard enthalpy of formation

30

## Standard state rules for a gas

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

31

## 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

32

## standard state rules for a substance in solution

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

33

## 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

34

## 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

35

## 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

36

## 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

37

## 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

38

## Units and symbol: frequency

###
Hz = 1/s

v

39

## units and symbol: wavelength

###
meters

lamduh, (upside down y)

40

## Wavelength definition

### the distance between two analogous points on successive waves

41

## amplitude definition

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

42

## frequency definition

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

43

## The greater the number the frequency the ______ the energy

### greater

44

## the greater the number of the wavelength the ____ the energy

### lower

45

## Frequency and amplitude are directly proportional to the _____

### energy

46

## frequency and wavelength are ______ proportional to the energy

### inversly

47