Final answer:
Density is the mass-to-volume ratio of a substance, defined as d = m/V, and it is true that it represents the relationship between mass and volume. Gases generally have lower densities than solids or liquids, and density can be affected by temperature changes.
Step-by-step explanation:
The statement that density is the relationship between mass and volume is true. Density, often represented by the symbol d, is an intensive property that defines the amount of mass per unit volume of a substance or object. The formula to calculate density is d = m/V, where m represents mass and V represents volume.
Gases are generally less dense than solids or liquids due to the larger spacing between their particles. Both liquid and solid materials exhibit a wide range of densities. This property can alter with changes in temperature, especially for liquids and gases.
For example, if you have a piece of iron with a mass of 23.4 grams and a volume of 3.00 cm³, the density of the iron would be calculated as follows: density (d) = mass (m) / volume (V) = 23.4 g / 3.00 cm³ = 7.80 g/cm³. This represents the mass-to-volume ratio of iron.