What is the density Of A 45-g block of wood that occupies 38.2cm3?

Density is mass divided by volume. The density of the block of wood is calculated as follows:

` d = m/V = (45 g)/( 38.2 cm^2) = 1.18 (g)/(cm^2)`

Density is a mathematical expression of how heavy something is for its size. It's a constant for a given material. If you have a block of the same wood that has twice the volume, then it will also have twice the mass since it has the same density as the first block of wood. 

Density must be expressed in mass units divided by volume units. Here are some other common units for density:

g/ml = one milliliter is the same volume as 1 cm^3 so this is the same as g/cm^3

kg/liter = density expressed in this unit is mathematically the same as in  g/cm^3 and g/ml, because 1 kg = 1000 g and 1 liter = 1000 ml.