Important equations (Y1. Drug delivery + Y2 equations)

The Stokes-Einstein Equation (diffusion coefficient)

The Noyes-Whitney Equation

Concentration unit = mg/ml

A level equation for Gibbs

∆G (Jmol^-1) = ∆H - T∆S

Equation that links Gibbs, Ideal gas constant, Temperature and Equilibrium Constant.

∆G (Jmol^-1) = -RTln(K). Can also be ka or kb

Equation that links pH, pKa, log(x), Total solubility and Unionised solubility.

Equation that links pKa and pKb

pKa + pKb = 14

Equation that links work, pressure and volume.

Work (J)= - Pressure (Pa) x Change in Volume (m^3)

Equation for Molar Enthalpy change (A-level).

Equation for enthalpy change (A-Level).

Equation that links Molar enthalpy change, Temperature and Change in entropy.

ΔH = TΔS

Equation that links Calorimeter constant (C), Change in internal energy of reactant (ΔU) and temperature (T).

ΔU (KJ) = C (kJ/K) x T (Kelvin)

Equation that links Internal energy of reactant (ΔU) , Moles and Enthalpy change.

ΔU (KJ) = mol (KJ) x ΔH (KJ/mol)

Van't Hoff's equation for ΔH.

If lots of values for Temp and K are available, Use the smallest values.

Show Van't Hoff's when rearranged to give an unknown equilibrium constant at a higher temperature (lnK2).

Equation that links Change in temp, Cryoscopic constant and molality.

How to calculate molality?

moles of solute/ solvent in kg

Quadratic equation

Always use + after -b

What does each letter in the quadratic equation refer too when calculating H+ and how do you calculate H+ from the calculated x value?

a = Concentration in question.

b = ka

c = -ka

Then multiply the calculated x value with the concentration in the question again to the H+ concentration.

Show the equation to find K using the rate of diffusion, surface area, solubility and concentration. (From the Noyes-Whitney equation)

Rate unit = kg s^-1

A unit = m^2

Cs unit = mg/ml

C unit = Kg m^3

How can rate of diffusion be calculated?

Noyes Whitney equation

or

Change in mass ÷ Change in time

Equation that links diffusion coefficient (D), K and thickness (h).

How do you calculate Osmolarity?

OsM = number of ions x moles

number of ions of NaCl = 2 as 1 Na+ and 1 Cl-

Henderson-Hasselbalch equation

Equation that links desired change in temp, change in temp at specific concentration and the difference of temp.

Equation that links pOH and pH.

pOH + pH = 14

Equation that links Ka, Kb and Kw.

Kw = Ka x Kb