General Chemistry/Useful Equations

Density:

{\frac {mass}{volume}}

Moles:

{\frac {given~mass~(g)}{gram~formula~mass}}

Percent Error:

{\frac {measured-accepted}{accepted}}\times 100\%

Percent Composition (by mass):

{\frac {mass~of~part}{mass~of~whole}}\times 100\%

Molarity:

{\frac {moles~of~solute}{volume~of~solution}}

Molality:

{\frac {moles~of~solute}{mass~of~solvent~in~kg}}

Rate of Reaction:

{\frac {Difference~in~quantity}{Difference~in~time}}

de Broglie's law:

\lambda

=

{\frac {h}{mv}}

Symbol	Meaning	Symbol	Meaning
$E$	energy	$c$	speed of light
$v$	frequency	$\lambda$	wavelength
$Q$	charge	$r$	distance
$k_{e}$	Coulomb's constant	$h$	Plank's constant H/nkne

Energy of Wave:

E=hv

Wave Relation:

c=\lambda v

Coulomb's Law:

F_{e}=k_{e}{\frac {Q_{1}Q_{2}}{r^{2}}}

Symbol	Meaning
$P$	pressure
$V$	volume
$n$	number of moles
$T$	temperature (in Kelvin)
$K_{f}$	molal freezing point constant
$K_{b}$	molal boiling point constant
$\chi$	mole fraction
$m$	molality
$M$	molarity
$c$	specific heat capacity
$M_{w}$	mass of water (Kg)
$E_{h}$	heat energy released

Rauolt's Law:

P_{solution}=P_{1}\chi _{1}+P_{2}\chi _{2}+\dots

Boiling Point Elevation:

\Delta T_{solution}=K_{b}\cdot m_{solute}

Freezing Point Depression:

\Delta T_{solution}=K_{f}\cdot m_{solute}

Ideal Gas Law:

PV=nRT

Combined Gas Law:

{\frac {P_{1}V_{1}}{n_{1}T_{1}}}={\frac {P_{2}V_{2}}{n_{2}T_{2}}}

Titration:

M_{A}V_{A}=M_{B}V_{B}

Dilution:

M_{1}V_{1}=M_{2}V_{2}

Heat released by burning:

E_{h}=cM_{w}\Delta T

Symbol	Meaning
$K_{eq}$	equilibrium constant (general)
$K_{p}$	pressure equilibrium constant
$K_{c}$	concentration equilibrium constant
$R$	gas law constant
$T$	temperature (in Kelvin)
$\Delta n$	moles of product – moles of reactant

pH:

\mathrm {pH} =-\log {[\mathrm {H^{+}} ]}

pOH:

\mathrm {pOH} =-\log {[\mathrm {OH^{-}} ]}

(for water):

\mathrm {pH} +\mathrm {pOH} =14

Pressure/Concentration:

K_{p}=K_{c}(RT)^{\Delta n}

Equilibrium, for a reaction $a\mathrm {A} +b\mathrm {B} \rightarrow c\mathrm {C} +d\mathrm {D}$ :

K_{eq}={\frac {[\mathrm {C} ]^{c}[\mathrm {D} ]^{d}}{[\mathrm {A} ]^{a}[\mathrm {B} ]^{b}}}

Heat Transfer:

q=mc\Delta T

Enthalpy:

\Delta H=H_{products}-H_{reactants}

Entropy:

\Delta S=S_{products}-S_{reactants}

Free Energy:

\Delta G=\Delta H-T\Delta S

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