Answer:
A chemical reaction is the change in chemical form rather than physical due to an outside force. This can come from something as simple as a change in temerature to as large as a specific element or compound.
The density is 4 g/cm³ or 4000 kg/m³.
Density = mass/volume = 12 g/3 cm³ = 4 g/cm³
The measurement of 4 g/cm³ is already in <em>SI units</em>.
In SI <em>bas</em>e units,
Density = (4 g/1 cm³) × (1 kg/1000 g) × (100 cm/1 m)³ = 4000 kg/m³