Download density

1.2: Density Calculations
Physical Science GPS Standards:
SPS2. Students will explore the nature of matter, its classifications, and its
system for naming types of matter.
a. Calculate density when given a means to determine a substance’s
mass and volume.
SCSh5. Students will demonstrate the computation and estimation skills
necessary for analyzing data and developing reasonable scientific explanations.
e. Solve scientific problems by substituting quantitative values, using
dimensional analysis and/or simple algebraic formulas as appropriate.
• density (D) = the relationship between the mass (m)
D=m
and volume (V) of a substance.
• acceptable units for mass include grams (g),
V
kilograms (kg), etc.
• acceptable units for volume include cubic centimeters (cm3),
liters (L), milliliters (mL), etc.
• acceptable units for density include those seen below:
Cross out the density unit that is NOT acceptable:
g/mL
L/kg
kg/L
g/cm3
Ex1: If 60 g of a liquid occupy a space of 20 mL, what is the density
of the liquid?
Ex1: If 60 g of a liquid occupy a space of 20 mL, what is the
density of the liquid?
1. given info & unknown
2. appropriate equation
3. plug in and solve, box answer
Three-Step Method: a simple method for solving any equation in
science, using the 3 steps described under the areas above.
Ex2: If a solid’s mass is 5.0 g and its volume is 2.0 cm3, what is its
density?
D=m
V
Ex2: If a solid’s mass is 5.0 g and its volume is 2.0 cm3, what is its
density?
1. given info & unknown
2. appropriate equation
3. plug in and solve, box answer
• the volume measurement of a density
problem can calculated in two ways:
• water displacement = method for
measuring the volume of an
irregular object.
• an object is dropped into a
measured amount of water in a
graduated cylinder or beaker.
D=m
V
• the volume measurement of a density
problem can calculated in two ways:
• water displacement = method for
measuring the volume of an
irregular object.
• an object is dropped into a
measured amount of water in a
graduated cylinder or beaker.
• the difference between the
initial volume of the water and
the new volume of the water is
equivalent to the object’s volume
Ex3: A pebble is dropped into a graduated cylinder containing 10
mL of water. The water level rises to 12 mL. If this pebble’s mass is
16 g, what is its density?
Ex3: A pebble is dropped into a graduated cylinder containing 10
mL of water. The water level rises to 12 mL. If this pebble’s mass is
16 g, what is its density?
1. given info & unknown
D=m
V
2. appropriate equation
3. plug in and solve, box answer
• measured size = method for
measuring the volume of a regular
object (such as a rectangular prism,
sphere, or cylinder) by measuring the
length of the sides/radius.
Ex4: A rectangular solid of unknown density is 5.00 cm long, 2.00
cm high and 3.00 cm wide. The mass of this solid is 90.0 grams.
Given this information for this material, calculate its density.
1. given info & unknown 2. appropriate equation
3. plug in and solve, box answer
Ex5: A sphere of unknown density has a
radius that measures 2.00 cm. The mass of
this solid is 134 grams. Given this info
for this material, calculate its density.
1. given info & unknown 2. appropriate equation
3. plug in and solve, box answer