For the first time, explicit, analytical expressions have been derived for the dependence of electrical conductivity, chemical expansion, and elastic modulus on defect concentration and oxygen partial pressure using a consistent approach. The models have been validated with experimental data for Ce0.9Gd0.1O1.95-delta (GDC) with consistently good fits. In developing the model, expressions were first derived for the functional dependence of defect concentration on the oxygen partial pressure (P-O2) for n-type fluorite oxides. Expressions for the chemical expansion, elastic modulus, and electrical conductivity as functions of defect concentration are then derived and verified with experimental data.