Final answer:
The density of the cube is 0.625 g/cm³.
Step-by-step explanation:
The density of a substance is calculated by dividing its mass by its volume. In this case, the mass of the cube is given as 5g and the volume of a cube is calculated by cubing the edge length. Since each side of the cube measures 2cm, the volume can be calculated as 2cm * 2cm * 2cm = 8cm³. Therefore, the density of the cube is 5g/8cm³ = 0.625 g/cm³.