The density of an object is given by dividing its mass by its volume. It is measured in kg/m³ (SI units) and other measurements such as g/cm³
Volume is measured in m³ (SI units) or cm³ . a cubic centimeter is equivalent to millimeter.
The volume of the rock is 9.5 ml which is 9.5 cm³
Thus mass = volume × density
= 9.5 × 2.6
= 24.7 g
Therefore, the mass of the rock will be 24.7 g