Chem 112 Equation Sheet-1 PDF

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Chem 112 EquationsThis document has been prepared for quick reference while you are studying, doing your assignments, or working on labs. Equations are organized by the chapter in which they were first presented. Practice problems in later chapters may require the use of equations from earlier chapt...

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Chem 112 Equations This document has been prepared for quick reference while you are studying, doing your assignments, or working on labs. Equations are organized by the chapter in which they were first presented. Practice problems in later chapters may require the use of equations from earlier chapters. Equations are NOT provided on exams and you will NOT be permitted to bring an equation sheet to the exam. You must memorize or be able to derive the equations you use on the exam.

Chapter One Converting between temperature (T) in °C and in K: T (in K) = T (in °C) + 273.15 Determining density (d), mass (m), or volume (V) from the following:

d=

m v

Perform calculations using dimensional analysis and conversion f actors: unit =desired unit or ( desired given unit ) given unit 1 1 = ( ) given unit desired unit desired unit

given unit

Chapter Two Determing mass number (A), number of protons (p), or number of neutrons (n): A = p + n Determining c harge, number of protons (p), or number of electrons (e):- charge = p – eNatural Abundance Relationships (mass average is mav, mass of isotope one is m 1, percent abundance of isotope one is P1): F1 = P1 ÷ 100% and mav = m1F1 + m2F2 (+ m3F3…) and 1 = F1 + F2 (+ F3…) Determining number of particles (usually atoms, molecules, or photons) or moles (n) using Avogadro’s number (NA): number of particles = nNA Determining molar mass (MM), mass (m), or moles (n): m = MMm

Chapter Three Determining Mass Percent Composition: 1

mass of X in 1 mol compound mass % of element X = ×100 % mass of 1 mol compound Determining molecular formula from empirical f ormula and molar mass:

molar mass compound empirical formula mass molecular formula =ratio×empirical formula ratio=

Chapter Four Calculating percent yield from actual and theoretical yield:

( theoretical yield )×100 %

% yield=

actual yield

Determining molarity (M), moles (n), or volume (V): M=

n V

Calculating molarity (M) or volume (V) for dilution of a solution: M1V1 = M2V2

Chapter Five P = pressure, PA = partial pressure of A, V = volume, T = temperature, n = moles, R = gas constant (included in data sheet), d = density, MM = molar mass, XA = molar fraction of A Applying Boyle’s Law: P1V1 = P2V2 Applying Charles’ Law:

Applying Avogadro’s Law:

V2 V1 = T 1 (in K) T 2 (in K ) V1 V 2 = n1 n2

Solving for n, P, V, or T using the Ideal Gas Law: PV = nRT Applying the equation for density of a gas:

d= 2

MWP RT

Solving for mole fraction: X = n A A n

total

Solving problems involoving partial pressures: Ptotal = PA + PB + PC… and PAV = nART and PA = XAPtotal Determining partial pressure when collecting gas over water: Pproduct = Patmosphere – Pwater

Chapter Six Applying the relationship between internal energy (E), heat (q), and work (w): ΔE = q + w Applying the relationship of heat (q), change in temperature (T), and heat capacity (C): q = C ΔT Applying the relationship between heat (q), mass (m), change in t emperature (T), and specific heat c apacity (Cs): q = m Cs ΔT Applying the relationship between work (w), pressure (P), and change in volume (V): w = - PΔV Calculating energy of reaction in a bomb calorimeter: qcal = Ccal ΔT and qrxn = - qcal and

Δ E=

qrxn n

Performing calculations for thermal energy transfer: q = m Cs ΔT and qmet = - qwater Determining enthalpy of reaction (ΔHrxn) in coffee cup calorimeter:

Δ H rxn=

qrxn n

Determining enthalpy of reaction (ΔHrxn) from heats of formation (ΔHf°) and stoichiometric coefficients (n): Δ H rxn=∑ n p Δ H f0, p −∑ n r Δ H f0 ,r

Chapter Seven Planck’s constant (h) and speed of light (c) are constant and can be found on data sheets c Applying the relationship of frequency (υ), speed of light (c), and wavelength ( λ): ν= λ Applying the relationship of energy (E), Planck’s c onstant (h), and frequency (υ): E = hυ 3

Applying the relationship of energy, Planck’s constant (h), speed of light (c), and wavelength hc (λ): E= λ Applying the De Broglie relation of wavelength ( λ ), Planck’s constant (h), mass (m), and velocity (v):

λ=

h mv

Determing the energy of an electron in an orbital with quantum number n in a hydrogen E n=−2.18×10−18 j atom:

( ) 1 n2

(

for transitions: Δ E=−2.18×10−18 j

1 n

2 f

−

1 2 ni

)

Chapter Eight Calculating Effective Nuclear Charge:

Zeff = Z(atomic number) – S(core electrons)

Chapter Nine Determining formal charge: Formal Charge = number of valence e- – number of non-bonding e- – number of bonds = group number (old periodic table) – number of non-bonding e - number of bonds Determining enthalpy change of a reaction from average energy in bonds (see example from lecture): Δ H rxn =∑ ( Δ H ' sbroken )−∑ ( Δ H ' s formed )

4...