What is the relationship between conductivity and resistivity, and how does temperature affect them?

Resistivity is the inverse of conductivity: Resistivity (ohm-cm) = 1/Conductivity (S/cm). Ultra-pure water has high resistivity (18.2 Megohm-cm at 25 degrees C) and low conductivity (0.055 uS/cm). Temperature significantly affects conductivity - typically 1-3% increase per degree C for aqueous solutions due to increased ion mobility. Temperature compensation is essential for accurate measurement; most instruments apply standard compensation (reference temperature 25 degrees C) using linear or matrix compensation. High-purity water applications often use resistivity; general applications use conductivity.