Wood has a density of 3.08 g/cm3. What is the volume of 21.9 g of wood?

Answer 1

So Kendra S.,

You start with two pieces of data, which have numerical values and units. Figure out how you can do a simple math operation on those two pieces, such that you can cancel the g's and end up with just cm^3 as a result. Then you will have done the correct math. This has the fancy name "dimensional analysis", by the way; you are using the "dimensions" (the units' names) to guide you to the desired "dimensions" (in this case, volume units) in the answer.

Good luck. 3 g cm^-3 is an absurdly high value by the way; even the most dense natural wood, lignum vitae, is only about 1.33 g cm^-3 .

-- Cheers, --Mr. d.

Answer 2

The density is a conversion factor that can be used to change the volume to mass (and mass to volume) of the given substance. Since the density of wood is given as 3.08g/cm3, we can say that 3.08 g of wood would occupy 1 cm3. We can also say that 1 cm3 of wood would weigh 3.08 g. For calculations I use dimensional analysis to show that the grams of wood cancel out, giving cm3 of wood.

21.9 grams of wood x 1 cm3 wood = 21.9 cm3 wood = 7.11 cm3 wood

3.08 g wood 3.08