IB Chemistry Data Booklet Quick Reference Cheat Sheet

Key Facts

• The gas equation is $pV = nRT$, where $R = 8.31\ \mathrm{J\ mol^{-1}\ K^{-1}}$ when pressure is in $\mathrm{Pa}$, volume is in $\mathrm{m^3}$, and temperature is in $\mathrm{K}$.
• Temperature must be converted using $T\left(\mathrm{K}\right) = T\left({}^{\circ}\mathrm{C}\right) + 273.15$ before it is used in gas law or thermodynamic calculations.
• Specific heat calculations use $q = mc\Delta T$, where $q$ is energy transferred, $m$ is mass, $c$ is specific heat capacity, and $\Delta T$ is the temperature change.
• Standard enthalpy change can be estimated from bond enthalpies using $\Delta H = \sum E_{\mathrm{bonds\ broken}} - \sum E_{\mathrm{bonds\ formed}}$.
• For a reaction $aA + bB \rightleftharpoons cC + dD$, the equilibrium expression is $K_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}$, excluding pure solids and liquids.
• The relationship between Gibbs free energy and equilibrium is $\Delta G^{\circ} = -RT\ln K$, so a larger $K$ gives a more negative $\Delta G^{\circ}$.
• The standard cell potential is $E^{\circ}_{\mathrm{cell}} = E^{\circ}_{\mathrm{cathode}} - E^{\circ}_{\mathrm{anode}}$, and a positive $E^{\circ}_{\mathrm{cell}}$ indicates a spontaneous cell under standard conditions.
• Acid-base calculations use $\mathrm{pH} = -\log[\mathrm{H^+}]$, $\mathrm{pOH} = -\log[\mathrm{OH^-}]$, and $\mathrm{pH} + \mathrm{pOH} = 14.00$ at $298\ \mathrm{K}$.

Vocabulary

Standard conditions

Standard conditions are the reference conditions used for many data values, commonly including $100\ \mathrm{kPa}$ pressure, $298\ \mathrm{K}$ temperature, and $1.00\ \mathrm{mol\ dm^{-3}}$ solutions.

Enthalpy change

Enthalpy change, $\Delta H$, is the heat energy transferred by a reaction at constant pressure.

Equilibrium constant

The equilibrium constant, $K_c$, is the ratio of product concentrations to reactant concentrations at equilibrium, each raised to its stoichiometric coefficient.

Standard electrode potential

Standard electrode potential, $E^{\circ}$, is the voltage of a half-cell measured against the standard hydrogen electrode under standard conditions.

pH

pH is a logarithmic measure of hydrogen ion concentration given by $\mathrm{pH} = -\log[\mathrm{H^+}]$.

Activation energy

Activation energy, $E_a$, is the minimum energy particles need for a successful reaction collision.