Final answer:
The density of a block with a mass of 12.8 g and dimensions of 3.5 cm by 8.4 cm by 2.1 cm is calculated by dividing the mass by its volume, resulting in a density of 0.209 g/cm³.
Step-by-step explanation:
The question asks us to calculate the density of a block with given dimensions and mass. To find the density, we can use the formula Density (D) = mass (m) / volume (V). First, we need to convert the mass from grams to cubic centimeters using the dimensions provided for length, height, and width of the block.
The mass of the block is 12.8 g, and the volume can be calculated by multiplying its length (3.5 cm), height (8.4 cm), and width (2.1 cm): Volume = 3.5 cm × 8.4 cm × 2.1 cm = 61.32 cm³. With the volume calculated, Density = 12.8 g / 61.32 cm³ = 0.209 g/cm³. The density should be rounded off to three significant figures because the volume measurement has three significant figures, thus the density of the block is 0.209 g/cm³.