Transcript Chapter 7 The Properties of Matter

Chapter 7
The Properties of
Matter
Objectives
SPI 0807.9.1 Recognize that all matter consists of atoms
SPI 0807.9.7 Apply an equation to determine the density of an object
based on its mass and volume
SPI 0807.12.4 Distinguish between mass and weight using appropriate
measuring instruments and units
SPI 0807.12.5 Determine the relationship among the mass of objects,
the distance between these objects, and the amount of gravitational
attraction
1.
2.
3.
4.
5.
Define new vocabulary terms: matter, volume, meniscus, mass,
weight, inertia
Describe the two properties of all matter
Identify the units used to measure volume and mass.
Compare mass and weight.
Explain how mass affects inertia.
Matter
• Anything that has
mass and takes up
space
• Everything has
matter
Volume
• Amount of space an
object takes up or
occupies
• All matter takes up
space
• No two things can
occupy the same
space at the same
time
• Measured in three
dimensions
Measuring Liquid Volume
• What tool is used to
measure liquid volume?
• Graduated cylinder,
measuring cups, spoons,
beakers
• Units: Liter (L) or
milliliter (mL)
• Meniscus – the curve at
the surface of the liquid
• Measure volume at the
bottom of the meniscus
Measuring volume of regular
shaped objects
• Solid objects expressed in cubic units
• Cubic meters (m3)or cubic centimeters (cm3)
• Volume = length x width x height
• Example: What is the volume of a box that has a length of 5
cm, a width of 1 cm, and a height of 2 cm?
• Step 1: Write the equation for volume
V=lxwxh
• Step 2: Replace the variables with the measurements given
to you and solve
V = 5 cm x 1 cm x 2 cm = 10 cm3
It’s Your Turn
• Calculate the volume for the following:
1. Cube with length of 5 cm
2. Box with height of 4 m, width of 8 cm, and length of 1 cm
3. Book with height of 25 cm, width of 18 cm, and length of 4
cm
4. CD case with 14.2 cm long, 12.4 cm wide, and 1 cm deep
Measuring volume of an Irregular
Shaped Object
• Water Displacement
1. Measure volume of water in graduated cylinder (initial
volume)
2. Carefully drop irregular object into grad. cylinder
3. Measure the volume of the water after the water level rises
(final volume)
4. Subtract the initial volume from the final volume
5. Units expressed in cm3
• Solid objects are never expressed in L or mL
Mass
• Amount of matter in
an object
• What has more matter,
an elephant or a
rabbit?
• The mass of an object
is the same no matter
where in the universe
the object is.
• How can you change
the amount of matter
in a object?
Weight
• Measure of gravitational force exerted on an object
• More mass → greater gravitational force on object → greater
weight
• Weight changes depending on location in universe
• Weigh less on moon than Earth
• Weigh more on Jupiter than Earth
Mass vs. Weight
Mass
• Amount of matter
• Always constant no
matter where located
• Measured with balance
• Units: kilograms (kg),
grams (g), milligrams
(mg)
• 100g = 1N
Weight
• Gravitational force on
object
• Varies depending on
location
• Measured with spring
scale
• Units: Newtons (N)
Inertia
• Tendency of an object to resist change in motion
• Object at rest will remain at rest until something causes it to
move
• Object in motion will stay in motion until something causes it
to stop or slow down
• Object with more mass is harder to make move and harder to
stop
Density
• Amount of matter in a given volume
• Every object has a different density
• Used to identify objects
• Density is the same no matter the amount of the object
• 100 g of silver has a density of 10.50 g/cm3
• 1 g of silver has a density of 10.50 g/cm3
• More dense → sink
• Less dense → float
• Density of water = 1 g/cm3
• If the density of the object is less than 1 g/cm3, the object will
float in water.
• If density is greater than 1 g/cm3, the object will sink in water
Calculating Density
Mass
• Density =
Volume
g
g
kg
• Units:
or
or 3
cm3
mL
m
• Example: What is the density of an object whose mass is 25 g
and whose volume is 10 cm3?
• Step 1: Write the equation for density.
D=
𝑚
𝑣
• Step 2: Replace m and V with the measurements given in the
problem, and solve.
25 𝑔
D = 10 𝑐𝑚3 = 2.5 g/cm3
Calculating Mass and Volume
• Rearrange the
density equation to
find mass and
volume
•V=
𝑚
𝐷
•m=DxV
Your Turn
1. Find the density of a substance that has a mass of 45 kg and
a volume of 40 m3.
2. A block of pine wood has a mass of 120 g. It has a width of
10 cm, length of 10 cm, and a height of 3 cm. What is the
density of the wood? Will this block of pine float or sink in a
pool of water? Why or why not?
3. What is the density of an object that has a mass of 350 g
and a volume of 90 cm3? Will the object float or sink in
water? Why or why not?
4. Suppose you have a lead ball whose mass is 454 g. Lead has
a density of 10 g/cm3. What is the ball’s volume?
5. What is the mass of a 15 mL sample of mercury? The
density of mercury is 13 g/cm3.
Objectives
• SPI 0807.9.1 Recognize that all matter consists of atoms
• SPI 0807.9.8 Interpret the results of an investigation to determine
whether a physical or chemical change has occurred
1.
2.
3.
4.
5.
6.
7.
8.
Define all new vocabulary terms: physical property, physical
change, ductility, malleability, solubility, thermal conductivity,
chemical property, chemical change, flammability, reactivity,
precipitate.
Identify six examples of physical properties of matter.
List six examples of physical changes.
Explain what happens to matter during a physical change.
Explain two examples of chemical properties.
List 6 examples of chemical changes.
Explain what happens during a chemical change.
Distinguish between physical and chemical changes
Physical Properties
• A characteristic that can be observed or measured without
changing the matter’s identity.
• Examples:
1. Magnetism
2. Heat conductivity
3. Strength
4. Flexibility
5. Odor
6. Volume
7. Color (sometimes)
Physical Properties
1.
Thermal conductivity - rate at which substance transfers heat
• Foam- poor conductor
• Metal - great conductor
2.
State – physical form in which a substance exists
• Solid, liquid, gas, plasma
3.
4.
Density – mass per unit volume
Solubility – ability of a substance to dissolve.
• Salt in water
• Drink mix in water
5.
Ductility – ability of a substance to be pulled into a wire
• Copper wire
6.
Malleability – ability of a substance to be rolled or pounded into
this sheets.
• Aluminum into foil
Physical changes
• A change of matter from one form to another without a
change in chemical properties.
• Do not change the identity of matter involved
• Examples:
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•
•
•
•
•
•
•
Change state
Change shape
Change color (sometimes)
Freezing water
Melting a popsicle
Tearing paper
Dissolving lemonade mix in water
Sanding a piece of wood
Chemical Properties
• The ability to change into new matter that has different
properties.
1. Flammability – ability of a substance to burn
• Burning wood
• Burning a match
2. Reactivity – ability of two or more substances to combine
and form one or more new substances.
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•
•
•
Reactivity with oxygen – rust (iron and oxygen)
Reactivity with acid
Reactivity with base
Reactivity with light
Chemical Changes
• A change that occurs when one or more substances change
into entirely new substances with different properties.
• Changes the identity of the substance
• Examples:
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•
•
•
•
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Soured milk
Rocket blast off
Effervescent tablet dissolving in water
Statue of Liberty turning green
Burning paper
Charcoal turning to diamonds
Baking a cake
Signs of chemical changes
• In most chemical changes, more than one sign is present.
1. Change in color (sometimes)
2. Change in odor
3. Production of heat
4. Bubbling
5. Fizzing or foaming
6. Sound or light given off
7. Gas given off
8. Precipitate formed (solid substance formed in solution)