Density Review
Mrs. O’Rourke
September, 2006
Question #1
• Density of different • Mercury, a metallic
items:
liquid element, has
a density of 11.3
– Gasoline—0.7 g/ml
g/ml. If you
– Water—1.0 g/ml
placed the metals
– Aluminum—2.7 g/cm3
listed to the left in
– Iron—7.3 g/cm3
mercury, draw and
– Silver—10.5 g/cm3
label a graduated
– Lead—11.3 g/cm3
cylinder that shows
– Gold 19.3 g/cm3
what would
happen?
Question #1 Answer
• The column should show that all
would float, except gold. The lead
could be shown as suspended in the
mercury.
Question #2
• Which of the following would float on pure
water?
– A. A substance with a mass of 1.33 g and a
volume of 1.38 mL.
– B. A substance with a volume of 3.35 mL and a
mass of 22. 64 g.
– C. A substance with a volume of 436.2 mL and
a mass of 418.23 g.
– D. A substance with a mass of 534.23 g and a
volume of 522.3 mL.
Question #2 Answer
• Both A and C would float on water.
Question #3
• Mass is equal to ????, while volume is
equal to ?????
–
–
–
–
A.
B.
C.
D.
Density/volume; mass/density
Density/volume; mass X density
Density X volume; mass X density
Density X volume; mass/density
Question #3 Answer
• D; mass is equal to density X volume;
volume is equal to mass/density.
Question #4
• Alicia has a pure gold coin that has a
mass of 120.24g. Gold has a density
of 19.3 g/cm3. What is the volume of
the coin?
Question #4 Answer
• 6.23 cm3
Question #5
• When water freezes it expands it’s
volume by 7%. What is the density
of ice?
–
–
–
–
0.30 g/mL
1.7 g/mL
1.07 g/mL
0.93 g/mL
Question #5 Answer
• 0.93 g/mL
Question #6
• Density of different
items:
–
–
–
–
–
–
–
Gasoline—0.7 g/ml
Water—1.0 g/ml
Aluminum—2.7 g/cm3
Iron—7.3 g/cm3
Silver—10.5 g/cm3
Lead—11.3 g/cm3
Gold 19.3 g/cm3
• Keshia has 3.0 cm3 of
gold, lead, silver, iron,
and aluminum. Which
of the following is
false?
– A. All of the samples
have different masses
– B. The aluminum has
the smallest mass
– C. The gold has the
greatest volume
– D. The silver has a
mass of 31.5 grams.
Question #6 Answer
• C; They all have the same volume:
3cm3. Gold would have the most
mass.
Question #7
• Jose has a 10 cm3 sample of silver while
Alicia has a 30 cm3 of silver. Which of the
following is false?
– A. Alicia’s sample has 3 times the volume of
Jose’s sample.
– B. Alicia’s sample has 3 times the density of
Jose’s sample.
– C. Alicia’s sample has 3 times the mass of
Jose’s sample.
– D. Jose’s sample has 1/3 the mass of Alicia’s.
Question #7 Answer
• B; density of an object does not
change when you ONLY cut it into
smaller pieces. You must heat it, cool
it, add a solute to the solvent, or
increase or decrease the pressure
on the substance to change the
density.
Question #8
• If you heat a sample of gas, the
density of the gas:
–
–
–
–
A.
B.
C.
D.
Remains the same
Decreases
Increases
Impossible to tell
Question #8 Answer
• B; when you heat a gas, the volume
expands due to the increase of the
speed of the molecules. The mass
would stay the same, volume would
increase, so density would decrease.
Question #9
• An object has these dimensions: The
length is 5 cm, the width is 2 cm, and
the height is 10 cm. What is the
volume?
• If the object has a mass of 65
grams, what is its density?
Question #9 Answer
• 100 cm3; 5 cm X 2 cm X 10 cm
• .65 g/cm3; 65g/100cm3
Question #10
• Your teacher gives you a little block
of metal which is exactly 1
centimeter square. It is small, but
has a mass of 4.5 grams. What is its
density?
Question #10 Answer
• 4.5 g/cm3; 4.5g/1cm3
Question #11
• A piece of metal has a mass of 3
grams and has a density of 2.70
g/cm3. What is its volume?
Question #11 Answer
• 1.11 cm3
Question #12
• A piece of foil has a volume of 0.90
cubic centimeters. If the foil is 30
centimeters by 18 centimeters, what
is its height.
Question #12 Answer
• .0016666 cm
– 30 X 18 X .0016666 = .90
Question #13
• A piece of aluminum foil has a mass
of 1.60 grams. It is 30 cm by 10 cm.
If we assume that the density of the
foil is 2.70 g/cm3, what is the
thickness of the foil?
Question #13 Answer
• .00197 or .002
Question #14
• A furniture maker wants to determine if
two pieces of wood are of the same type.
He knows that the two woods have
different densities. The first piece is 30
X 14 X 2.5 cm and has a mass of 350
grams. The second piece is 15 X15 X 10 cm
and has a mass of 900 grams. Are they
different types of wood?
Question #14 Answer
• yes; the density of the first piece is
.33 g/cm3, the density of the second
piece is 1.2 g/cm3.
Question #15
• When salt is added to water the density
increases. Marine biologists use this
characteristic to measure the salinity in
sea water. A biologist knows that the
density of the water must be between 1.05
and 1.08 g/cm3. She finds that 80 mL has
a mass of 83.2 grams. Is this water within
the limits?
Question #15 Answer
• No, It is only 1.04 g/mL, so the
salinity level is too low.
Question #16
• 28.5g of iron shot is added to a
graduated cylinder containing 45.50
mL of water. The water level rises to
the 49.10 mL mark. What is the
density of iron?
Question #16 Answer
• 7.9166 or 7.92 g/cm3
Question #17
• A piece of wood that measures 3 X 6
X 4 cm has a mass of 80 grams.
What is the density of the wood?
• Would it float in water?
Question #17 Answer
• 1.11 g/cm3
• No, it will not float. It is more dense
than water.
Question #18
• A cup of gold colored beads was measured
to have a mass of 425 grams. By water
displacement the volume of the beads was
calculated to be 48.0 cm3. Given the
following densities, identify the metal:
• Gold: 19.3 g/cm3
• Copper: 8.86 g/cm3
• Bronze: 9.87 g/cm3
Question #18 Answer
• copper
Question #19
• Lynn threw a plastic ball into his pool for
his dog to fetch. The mass of the ball was
125 grams. What must the volume be to
have a density of 0.50 g/cm3. (He wants it
to float, of course!)
• After throwing the ball into the pool, it
sprang a leak and began to fill up with
water. How many mL of water can the ball
absorb before the ball sinks?
Question #19 Answer
• The ball must have a volume of 250
cm3.
• When the ball has absorbed 126 mL
it will sink
Question #20
• What is the mass of a cylinder of
lead that is 2.50 cm in diameter and
5.50 cm long? The density is 11.4
g/cm3.
Question #20 Answer
• 97.926 or 97.93 g
Question #21
• An ice cube measuring 5.80 cm by
5.80 cm has a density of 0.917 g/mL.
What is the mass of the ice cube?
Question #21 Answer
• 178.9177 or 178.92 g
Question #22
• Gasoline is non-polar liquid that will
float on water. 450 grams of
gasoline is spilled into a puddle of
water. If the density of gasoline is
0.665 g/mL, what volume of gasoline
was spilled?
Question #22 Answer
• 676.69 mL
Question #23
• A little aluminum boat (mass of
14.50g) has a volume of 450.00 cm3.
The boat is placed in a small bucket
of water and carefully filled with
pennies. If each penny has a mass of
2.50g, how many pennies can be
added to the boat before it sinks?
Question #23 Answer
• 175 pennies
• Mass to volume must be greater than 1.
450 mL would need to have just over 450 g
to sink. We have 14.5 g. 450 – 14.5 =
435.5g
• 435.5/2.5 (gram per penny) = 174.2. So
you must add 175 pennies to sink your
boat.
Question #24
• A sample of the mineral pyrite has a
mass of 150g and a volume of 30 cm3.
What is the density of pyrite?
• If I cut my sample of pyrite in half;
what would its new mass, volume, and
density be?
Question #24 Answer
• The density of pyrite would be 5
g/cm3.
• If the sample were cut in half, the
mass and volume would as be cut in
half; however, the density would not
change. New mass: 75g. New
volume: 15 cm3.