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Lecture 1.14 Density
Density = Mass / Volume
Density Units: g/mL or g/cm3 or g/cc
Objective: Understand the facts about density:
1. The density of a given mass of a substance is temperature dependent. Therefore, changes in
temp will cause changes in density.
2. Density is a convenient conversion factor when you need a specific mass of a liquid. For
example, it is difficult to weigh out 15mL of liquid B. It is much more precise to measure out
15mL of liquid B using a graduated cylinder. Calculate the mass using algebra if the density of
liquid B is .987g/mL.
DxV=M
.987g/mL x 15mL = 14.80 or 15g
Why does ice float when it is a solid and water is a liquid? Shouldn’t it be more dense and
sink?
Objective: Practice Density Calculations:
1. Milk has a density of 1.03 g/mL at room temp.
Calculate the mass of 1L of milk.
density = mass/volume
So mass = density x volume
Convert 1L to mL: volume = 1L x 1000mL/L = 1000mL
mass = 1.03g/mL x 1000mL = 1030g or 1.03 x 10 3g (=1.030kg)
2. A diamond has a density of 3.5 g/cm3.
Calculate the volume of 0.5g of diamond.
density = mass/volume
So, volume = mass/density
volume = 0.5g/3.5g/cm3 = 0.14cm3
Homework Problems:
1. Blood cells have a mean cell volume of 9.0 x 10 -14 L. Is this an appropriate unit to measure
the volume of a blood cell? Why or why not? Convert this to cc, then calculate the density of a
5 gram blood sample.
(9.0 x 10 -14 L/1) (1000cc/1L) = 9.0 x 10 -11cc
D = M/V 5g/9.0 x 10 -11 cc D = 5.6 x 10 10 g/cc
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