Final answer:
The volume of the metal is calculated using the formula: Volume = Mass / Density. With a mass of 21.0 g and a density of 2.7 g/cm³, the volume comes out to be 7.777... cm³, which rounds to 7.8 cm³, making option A) the correct answer.
Step-by-step explanation:
To find the volume of the metal, we use the formula: Volume = Mass / Density. Given that the density of the metal is 2.7 g/cm³ and the mass is 21.0 g, the volume would be:
Volume = Mass / Density = 21.0 g / 2.7 g/cm³ = 7.777... cm³
When rounded to the nearest tenth, this gives us a volume of approximately 7.8 cm³, which corresponds to option A).