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An object has a mass of 30 kg and a volume of 5 liters. What is its density?
An object has a volume of 11 mL and a mass of 419 g. What is its density?
A rock has a density of 20.0 g/cm 3 . What would the volume of 340 g of this rock be?
Watch sig figs, units, & circle answers!
A rock has a density of 20.05 g/cm 3 . Jesse fills a graduated cylinder to a volume of 25.0 ml. He drops a sample of the rock into the g.c. and the water level rises to 29.5 ml.
What is the mass of the sample? Show all work, round to the correct number of significant figures, and circle your answer.
Give 3 units for volume.
Give 3 units for mass.
Give 3 units for density.
A stack of nickels has a density of 8.6 g/cm 3 and a volume of 7.5 cm 3 . What is the mass of the nickels?
A kiwi has a mass of 111.5 g and a density of 0.95 g/cm 3 . What’s it’s volume?
A 5.0 kg object has a volume of 3.0 liters. What’s its density?
An object with a density of 5.0 g/cm3 has a mass of 75.0 g. What is the object’s volume?
A block has dimensions 5.0 cm by 3.0 cm by 2.0 cm and a mass of 75.0 g. What is it’s density?

 Golf ball & grad cyl
 Mercury & water
 Ping pong ball, rocks, & steel ball
 Orbits bottle
 Box of density stuff to measure
 Graduated cylinder & scale

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What is volume? Units?
What is mass? Units?
What is density? Units?

Today you are going to… take notes on density & do some density problems
So you can… understand & calculate density, make predictions based on density
You’ll know you’ve got it when you can answer the notes questions & density problems

 Hg & H
2
O
 Compare volume, mass, & density

 Density is the ratio of an object’s mass to its volume.
 Density = mass/volume
 Units of g/ml, kg/L, g/cm 3, lb/gal, lb/ft 3
 Water has a density of 1 g/ml
 1 g / cm 3 = 1000 kg / m 3
 5 g/mL means that every 1 mL of the liquid has a mass of 5 grams!

 The density of a pure substance is always the same , no matter what size it is.
(statue of liberty example)

 The composition was pure copper from 1793 to 1837.
 From 1837 to 1857, the cent was made of bronze (95 percent copper, and five percent tin and zinc).
 From 1857, the cent was 88 percent copper and 12 percent nickel, giving the coin a whitish appearance.
 The cent was again bronze (95 percent copper, and five percent tin and zinc) from 1864 to 1962.
(Note: In 1943, the coin's composition was changed to zinc-coated steel. This change was only for the year 1943 and was due to the critical use of copper for the war effort.)
 In 1962, the cent's tin content, which was quite small, was removed.
That made the metal composition of the cent 95 percent copper and 5 percent zinc.
 The alloy remained 95 percent copper and 5 percent zinc until 1982, when the composition was changed to 97.5 percent zinc and 2.5 percent copper (copper-plated zinc). Cents of both compositions appeared in that year.

 A pure substance always has the same density!
 The density is the same no matter how much or little of it you have.
Metal Density g/cm 3
Aluminum
Brass
Copper
Gold
Iron
Lead
Nickel
Platinum
Silver
Steel
Tin
Titanium
Zinc
2.7
8.4 – 8.7
8.9
19.3
7.9
11.3
8.8
21.4
10.5
7.5 – 8.0
7.3
4.5
7.1

 As you pass around these objects, put them in order of least to most dense.
A. shiniest block
B. other silver colored block
C. yellow block
D. Styrofoam ball
E. marble

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If it’s more dense than a liquid, it’ll __________ in it.
If it’s less dense than a liquid, it’ll __________ in it.
 Water has a density of 1.00 g/mL.
 Orbits, ping pong ball, golf ball
 Something with the same density as a liquid will ______.
 Cannonball in mercury

 Golf balls
 Metal sphere ball in rocks changes!

Ball of paper
Add mass to cup
(do briefly, more in depth tomorrow)

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Define mass in your own words.
Define volume in your own words.
Define density in your own words.
Fundamental or derived units?
What changes when you drink the pop out of a can?
What changes when you crush the can?
Compare a Styrofoam peanut and a grain of sand.

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The U.S. first struck 5¢ nickel coins in 1866. All nickels from that date to the present except for the famous "war nickels" (mid-1942 to 1945) are made of the same metal, an alloy of 75% copper and 25% nickel. "War nickels" were made of 35% silver, 56% copper, and 9% manganese because nickel was needed for the war effort. These coins are distinguished by the extra large mint mark over the dome of Monticello. They have been worth up to 90¢ for their silver content. In August 2009, the value of the metal in the standard nickel was about 5 cents, due to the rising costs of copper and nickel.

Relationship between mass, volume, & density.
 Mass is directly related to density.
 If mass doubles, density doubles.
 If mass triples, density triples.
 If mass halves, density halves.
 Volume is inversely related to density.
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If volume doubles, density “halves”.
 If volume triples, density is 1/3.
 If volume halves, density doubles.

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Now we’ll calculate the density of the objects!
 For which objects did it seem extremely easy to compare the density?
 To measure the volume of regularly shaped objects
(cubes & rectangles) we measure the sides.
 A. shiniest cube
 B. other silver colored cube
 C. yellow cube

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If you increased the mass of an object while keeping it’s volume constant, what would happen to it’s density?
If you increased the volume of an object while keeping it’s mass constant, what would happen to it’s density?
What does inverse mean?

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Put your homework upsidedown (facing me) on your desk.
55.0 liters of a liquid has a mass of 41 kg. What is it’s density?
Would it float in water?
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A rock has a density of 20.0 g/cm 3 . What would the volume of
340 g of this rock be?
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What is the volume of a 2 cm x 3 cm x 5 cm rectangle?
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When you finish, work on the back of your density worksheet.

Today you are going to… review density hw & finish the back
So you can… solve density problems & complete tomorrow’s lab recognize how problems are graded
You’ll know you’ve got it when you can answer the questions on the back of the worksheet

Practice A 58.00 mL sample of a liquid has a mass of
600.74 g. What is its density?

Practice A 58.00 mL sample of a liquid has a mass of
600.74 g. What is its density?

Practice A 58.00 mL sample of a liquid has a mass of
600.74 g. What is its density?

3. A 58.00 mL sample of mercury has a mass of 784.74 g.
What is its density?

5. Pure gold has a density of 19.32 g/cm 3 . How large would a piece of gold be if it had a mass of 318.97 g?

6. A 200 cm 3 sample of silver has a density of 10.5 g/ cm 3 .
What is it’s mass?

Like # 12: Josh notes that 40.0 cm 3 of a certain metal has a mass of 180.0 g. What would the mass of 295 cm 3 be?

A brick of gold has the dimensions of 17.8 x 19.21 cm x 4.45 cm.
What would its mass be? Convert this to kilograms. IF each kilogram weighs 2.2 lbs, how much would the gold bar weigh?

Tommy observed that 7.00 cm 3 of a certain metal has a mass of 55.5 g. What would the mass of 45.0 cm 3 of the metal be?

Homework upsidedown on desk!!
1. Josh notes that 40.0 cm 3 of a certain metal has a mass of 180.0 g.
What would the mass of 295 cm 3 be? Would it float in water?
Would it float in mercury?

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Sydney nicole jacob
Jessica hillary joshua
Tanner nick bailey
Andrew dylan damon
Rachel destiny thomas hannah
Jon alida emma
Angelo jen angelina
Zan adam ian
Zach alex bryan

 1 – Alcohol blue
 2 Salt water pink
 3 water purple
 4 corn oil - yellow

Today finish density preview density rainbow lab
Friday density rainbow lab
Monday quiz on density; start factor label
Tuesday factor label
Wednesday factor label quiz
Thursday review
Friday test

Object
Shiniest cube
Other cube
Yellow cube
Golf ball
Marble
Mouse ball
Zinc cylinder
Silverish wire
Mass (g) Volume (cm 3 ) Density

 The density of gold is 19.3 g/cm 3 . What would the volume of 1 oz of gold be? (1 oz = 28.3 g)

 Good tutors

Explain how and why, don’t just do the problem
 Ask questions to help lead to understanding
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Don’t give up!
 Good learners
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Ask questions when they don’t understand
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Don’t give up!

 First, you must be able to identify your variables.
 16.0 g
 25 g/mL
 0.56 kg/L
 85 cm 3
 250 L
 35 kg
 20 mL
 6.023 g/cm 3
 85 m 3

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The sides of a rectangle measure 0.5 cm x 1.0 cm x 1.5 cm, and it has a mass of 2.25 g. What is it’s density?
2.
Your trying to find the density of a 30.0 g irregularly shaped object. You put some water in a graduated cylinder and measure the water level to be 20.0 mL. You drop the object in, and the water level rises to 25.0 mL. What’s the object’s density?

 Density Triangle - Cover the letter of the variable you want to find and you will have the formula!
 For example, if you cover the "V", you will see the formula for volume is mass/density.
 This can be done with any formula like this!

 25 mL (milliliters) of liquid has a mass of 50 g
(grams). What is the liquid’s density?

 25 mL (milliliters) of liquid has a mass of 50 g
(grams). What is the liquid’s density?
D = M = 50 g = 2 g/ml
V 25ml

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An object has a mass of 30 kg and a density of 5 g/mL. What is its volume?

1. An object has a density of 10.0 g/mL and a mass of 419 g. What is its volume?

1.
A rock has a density of 20.05 g/cm 3 . Jesse fills a graduated cylinder to a volume of 25.0 ml. He drops a sample of the rock into the g.c. and the water level rises to 29.5 ml. What is the mass of the sample? Show all work, round to the correct number of significant figures, and circle your answer.

(Include units & tell if each will sink or float)
1. A random solid has a mass of 24 g and a volume of 35 mL. What is its density?
2. An object has a mass of 18 kg and a volume of 3 liters.
What is its density?
3. An object has a volume of 10.0 cm 3 and a mass of 73 g.
What is its density?
4. If 60 mL of liquid has a density of 0.70 g/mL, what is its mass?
5. An object has a mass of 36 g and a density of 2.5 ml/g.
What is its volume?

 Archimedes' principle: When a body is fully or partly immersed in a liquid, that body experiences an upward force (the buoyant force) equal to the weight of the displaced liquid. The displaced liquid is that volume of liquid equal to the volume of the body below the water surface.
 Density of Penny 3.11 grams [pre 1982]
 2.50 grams [post 1982]
 Density of nail = 8.04 g/ml
 Density of alcohol = 0.789 g/ml

 Show all of your work for all 4 objects (16 pts)
 Finding volume, equation, equation with substitution, answer with units
 4 points for behavior
 Stay in own group
 Only take one item at a time
 Clean up

 Show setup/procedure for finding density

 Density of water
(@ 4 o C)
= 1.000 g/ml = 1.000 kg/L
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Gram was defined as “mass of 1 mL of water”
 More dense than water
 sinks
 Less dense than water
 floats
 Same density
 can be suspended anywhere in it something with the same density as water will level out in the middle. (show examples of each)

 1. What changes when you drink the pop out of a can?
 2. What changes when you crush the can?
 3. Define mass in your own words.
 4. Define volume in your own words.
 5. What has more volume, a Styrofoam peanut or a marble?

 25 mL (milliliters) of liquid has a mass of 50 g
(grams). What is the liquid’s density?

 25 mL (milliliters) of liquid has a mass of 50 g
(grams). What is the liquid’s density?
D = M = 50 g = 2 g/ml
V 25ml

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Identify variables – units are clues!
Write formula
Substitution
Circle answer with correct sig figs & units

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 Density Triangle - For whatever you're trying to solve for, cover that letter with your finger and you will have the formula! For example, if you cover the "V", you will see the formula for volume is mass/density.
(review how to find it)

Density Problems (Include units, correct # of sig figs, & tell if each will sink or float in water)
1.
A random solid has a mass of 24.0 g and a volume of 35 cm 3 . What is its density?
2.
A liquid has a mass of 18 kg and a volume of
3.00 liters. What is its density?

Density Problems (Include units, correct # of sig figs, & tell if each will sink or float in water)
3.
A liquid has a volume of 10.0 mL and a mass of
7.30 g. What would the mass of 97 mL of the liquid be?

1.
Sam measures the mass of a metal ball on a balance and it reads 50.56 g. She drops the metal ball into a graduated cylinder and the water level goes from 25.5 mL to 28.8 mL. What would the volume of a of 5.5 kg metal ball be?

Density Problems (Include units, correct # of sig figs, & tell if each will sink or float in water)
4.
If 60 mL of liquid has a density of 0.70 g/mL, what is its mass?
5.
An object has a mass of 36 g and a density of 2.8 ml/g. What is its volume?

Density Lab Problem
Dan masses a metal cylinder and the balance reads 22.35 g. He drops it into a graduated cylinder with some water in it, and the water level goes from 34.5 mL to 39.0 mL. What is the density of the metal cylinder?

Density Lab Problem Too
Abbey masses a wooden block and the balance reads 22.35 g. She measures the sides & finds the block to be 3.0 cm by 4.0 cm by 6.0 cm. What is the density of the wooden block?

Density Problems (Include units, correct # of sig figs, & tell if each will sink or float in water)
1. A random solid has a mass of 24.0 g and a volume of 35 cm 3 . What is its density?
2. A liquid has a mass of 18 kg and a volume of
3.00 liters. What is its density?
3. A liquid has a volume of 10.0 mL and a mass of
7.30 g. What would the mass of 97 mL of the liquid be?
4. If 60 mL of liquid has a density of 0.70 g/mL, what is its mass?
5. An object has a mass of 36 g and a density of 2.8 ml/g. What is its volume?

Density Problems (Include units, correct # of sig figs,
& tell if each will sink or float in water)
1. A random solid has a mass of 24.0 g and a volume of 35 cm 3 . What is its density? 0.69 g/ cm 3 Float
2. An object has a mass of 18 kg and a volume of 3.00 liters. What is its density? 6.0 g/L Sink
3. A liquid has a volume of 10.0 mL and a mass of 7.30 g. What would the mass of 97 mL of the liquid be?
0.730 g/mL 70.8 g Float
4. If 60 mL of liquid has a density of 0.70 g/mL, what is its mass?
4 g Float
5. An object has a mass of 36 g and a density of 2.8 ml/g.
What is its volume?
1300 mL Sink