Cheatography

# Chemistry Final Equations Cheat Sheet by katherinedoucet

math equations from all chapters

### Exam 1

 Kelvin to Celsius K=C +273 Fahrenheit to Celsius F=9F/5C (C) + 32F density d=m/V SI: kg/m3; g/mL or g/cm3 commonly used moles to atoms and molecules 1 mole = 6.022 x 1023 atoms or molecules moles to grams 1 mole = atomic mass (g) 1 mole = formula mass (g) grams to atoms or molecules atomic mass (g) = 6.022 x 1023 atoms formula mass (g) = 6.022 x 1023 molecules avagadro’s number 6.022 x 1023 moles kinetic energy of a moving object Ek = 1/2 mu2 u: velocity electr­ostatic energy Eel = Q1Q2/d Q1 and Q2: product of charges; d: distance between charges joule 1 J = 1kg x m2/s2 1 J = 1 N x m speed, wavele­ngth, and frequency c = (wavel­eng­th)(v) c: speed of light - 3.00 x 108 m/s; wavele­ngth: in meters; frequency (v): in s-1 or Hz energy of a photon E = hv h: 6.63 x 10-34 J x s; v: frequency in s-1 or Hz energy (hv) of a photon used to eject electrons from a metal surface via the photoe­lectric effect is equal to the sum of kinetic energy of the ejected electron (Ek) and the work function (W) hv = Ek + W Ek = hv - W wavelength of emitte­d/a­bsorbed light when an electron transi­tions from one quantum state to another 1/wave­length = 1.097 x 107 m-1(1/n(f)2 - 1/n(i)2) difference in energy between two quantum states E = hv = -2.18 x 10-18 J (1/n(f)2 - 1/n(i)2) energy of an electron with a given quantum state En = -2.18 x 10-18 J (1/n2) wavelength of emitte­d/a­bsorbed light 1/wave­length = 2.18 x 10-18 J/hc (1/n(f)2 - 1/n(i)2) de broglie wavelength wavelength = h/mu m: mass of particle in kg; u: velocity of the particle in s-1 or Hz heinse­nberg uncert­ainty principle deltax x deltap > h/4pi deltax x mdeltau > h/4pi position of particle: x; momentum of particle: p (defined as mass times velocity) energy and wavelength E = hc/wav­elength wavelength = hc/E charge of a single electron -1.6022 x 10-19 C C: coulombs atomic mass units (amu) 1 amu = 1.66 x 10-24 g 1 amu = 1.66 x 10-27 kg angstrom 1 A = 1 x 10-10 m mass of a single electron 9.10 x 10-28 g mass of a proton 1.67262 x 10-24 g charge­-to­-mass ratio of an electron 1.76 x 108 C/g

### Exam 2

 effective nuclear charge (Zeff) Zeff = Z - o Z: number of protons; o: shielding constant or number of core electrons force (coulomb’s law) F = Q1Q2/d2 ionic EN difference > or equal to 2.0 polar EN difference .5 - 2.0 nonpolar (or purely covalent) EN difference < .5 % by mass of an element = n x atomic mass of elemen­t/m­ole­cular or formula mass of compound (100%) % ionic character = u (obser­ved)/u (calcu­lated) (100%) u: dipole moment dipole moment u = Q x r u: dipole moment (in debeye units (D)); Q: charge magnitude; r: distance between charges (bond length) 1 D = 3.336 x 10-30 C x m charge magnitude Q = u/r formal charge = valence electrons - (all nonbonding electrons + 1/2 bonding electrons) electr­one­gat­ivity EN = IE1 + EA /2 coulomb 1 C = 6.242 x 1018 electron charge

### Exam 3

 bond order = number of electrons in bonding MO - number of electrons in antibo­nding MO/2 atom economy = sum of molar mass of desired produc­t/sum of molar mass of reactants % yield = actual yield/­the­ore­tical yield (100%)

### Exam 4

 molarity M = moles solute/L solution dilution Mc x Lc = Md x Ld Mc x mLc = Md x mLd (product in millim­oles) c: concen­trated; d: diluted kinetic energy Ek = 1/2 mu2 average kinetic energy of a group of gas molecules u2 = uN2/N u2: average speed for all the molecules in the sample; mean square speed N: number of molecules in sample total kinetic energy of one mole of any gas Ek = 3/2 RT R: 8.314 J/K x mol T: temper­ature in Kelvin root-m­ean­-sq­uar­e-speed Urms = square root of 3RT/molar mass R: 8.314 J/K x mol molar mass in kg/mol comparing Urms values of molecules in different gas samples Urms(1­)/U­rms(2) = square root of molar mass (2)/molar mass (1) graham’s law rate = 1/square root of molar mass rate of diffusion or effusion is inversely propor­tional to the square root of the molar mass pressure P= force/area SI unit of force: Newton (1 N = 1kg x m/s2) SI unit of pressure: pascal (Pa; 1 Pa = 1 N/m2) pressure exerted by a column of fluid P = hdg P: pressure in Pa h: height of column in meters d: density of fluid in kg/m3 g: gravit­ational constant - 9.80665 m/s2 boyles law P1V1=P2V2 pressure of a fixed amount of gas at constant temper­ature is inversely propor­tional to the volume of the gas charles law V1/T1=­V2/T2 volume of a fixed amount of gas at constant pressure is directly propor­tional to the absolute temper­ature of the gas avogadros law V1/n1=­V2/n2 volume of a sample of gas at constant temper­ature and pressure is directly propor­tional to the number of moles in the sample combined gas law P1V1/n­1T1­=P2­V2/n2T2 P1V1/T­1=P­2V2/T2 ideal gas equation PV=nRT R: 0.08206 L x atm/K x mol T and n: K and mol P and V: atm and L density of a gas d = P(molar mass)/RT molar mass in kg/mol R: 0.08206 L x atm/K x mol molar mass of a gas molar mass = dRT/P R: 0.08206 L x atm/K x mol molar mass: in kg/mol van der waals equation (P + an2/V2)(V - nb) = nRT a and b depend on the element compre­ssi­bility factor Z = PV/RT partial pressure P total = sum of partial pressures mole fraction Xi = ni/n total Xi = Pi/P total Xi x n total = ni Xi x P total = Pi amount of reactant consumed n = P x (V/RT) at constant volume and temper­ature n: number of moles consumed P: change in pressure pressure exerted over water P total = P O2 + P H2O