Final answer:
The density of a rock is found by measuring its displaced volume in a graduated cylinder and its mass. The rock's density is calculated as the mass divided by the volume, resulting in a density of approximately 1.08 g/cm³.
Step-by-step explanation:
To determine the density of the rock, we need to calculate its volume and then use the mass to calculate density. The volume of the rock can be found by measuring the increase in water level when the rock is submerged in the graduated cylinder. The water level rises from 42.8 mL to 49.5 mL, indicating the rock displaces 6.7 mL of water, which is equal to the volume of the rock since 1 mL of water is equivalent to 1 cm³. With the mass of the rock being 7.25 g, the density can be calculated using the formula: Density = Mass/Volume. Therefore, the density of the rock is 7.25 g / 6.7 cm³, which equals approximately 1.08 g/cm³.