The model contains one compartment called "compartment". There are four species named S1, S2, S3 and S4 and two parameters named k1 and k2. Compartment "compartment" is 0-dimensional. Species S4 is labeled as constant and therefore cannot be changed by rules or reactions. The model contains two reactions defined as:

Reaction Rate
S1 + S2 → S3 k1 · S1 · S2
S3 → S1 + S2 k2 · S3 · S4

The initial conditions are as follows:

Value Units
Initial amount of S1 1.0 × 10−3 mole
Initial amount of S2 1.5 × 10−3 mole
Initial amount of S3 0.75 × 10−3 mole
Initial amount of S4 1.25 × 10−3 mole
Value of parameter k1 1.68 × 103 mole-1 second-1
Value of parameter k2 0.27 × 103 mole-1 second-1

In this example the compartment has its spatialDimensions attribute set to zero; i.e., it represents a point and therefore cannot have size or units. The species values must be treated as amounts and not concentrations.