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Do Now! September 25, 2012. Another T-chart!!!!!!!!!!!!! It’s the last one…. For now. Which are physical properties? Which are chemical properties?. TemperatureColorTarnish (think jewlery) Melting PointOdorHardness RustingAmount Combustion (think gasoline). - PowerPoint PPT Presentation
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Do Now!September 25, 2012Another T-chart!!!!!!!!!!!!!Another T-chart!!!!!!!!!!!!!It’s the last one…. For now.It’s the last one…. For now.
• Which are physical properties?• Which are chemical properties?
Temperature Color Tarnish (think jewlery)Melting Point Odor HardnessRusting Amount
Combustion (think gasoline)
THEN… Work on the Ch. 13 Sec. 1 ASSESSMENT QUESTIONS pg. 545
Physical Properties Chemical Properties
WednesdaySeptember 26, 2012
Fe2O3 What is the ratio of atoms of iron (Fe) to atoms of oxygen (O) in this compound?
Iron to oxygen is ____ to _____Iron:oxygen = _____:____
What about for the compound AlCl3? What is the compound and what is the ratio of atoms?
ThursdaySeptember 27, 2012
Find the volume of your science Find the volume of your science textbook and of another textbook and of another
object at your desk (of your object at your desk (of your choosing). List ALL steps on choosing). List ALL steps on
your Do Now page.your Do Now page.Rulers are on my desk.Rulers are on my desk.
Do the following problems:*Remember!* write every step of the problem!!
V = L x W x HD = m/V
What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm3?
The density of water is 1 g/cm3. A piece of wood that measures 3.0 cm by 6.0 cm by 4.0 cm has a mass of 80.0 grams. What is the density of the wood? Would the piece of wood float in water? (volume = L x W x H)
What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm3?
A piece of wood that measures 3.0 cm by 6.0 cm by 4.0 cm has a mass of 80.0 grams. What is the density of
the wood? Would the piece of wood float in water? (volume = L x W x H)
I threw a plastic ball in the pool for my dog to fetch. The mass of the ball was 125 grams. What must
the volume be to have a density of 0.500 g/mL. ( I want it to float of course!)
Measuring Matter
Chapter 13Chapter 13Section 2Section 2
DiscussDiscuss (by raising your hands, people)
How do we measure matter?
What do we use to measure matter?
What is the difference between weight and mass?
A riddle…
Which weighs more, a pound of feathers, or
a pound of sand?
….. They weigh the same! One pound!
Weight & Mass
• Suppose you want to measure your weight.• As you step on a scale, your body weight
presses down on the springs inside.• The more you weigh, the more the springs
compress, causing the pointer on the scale to turn farther, giving a higher reading.
• If you took this exact scale to the moon, would it indicate the same weight?
Weight
Your weight is a measure of the force of gravity on you.
On Earth, all objects are attracted toward the center of the planet by
the force of Earth’s gravity.
MassThe mass of an object is the measurement
of the amount of matter in the object.
If you travel to the moon, the amount of matter in your body – your mass – does
not change.
? ? ?
Does anyone know why the moon has such a small
gravitational pull?
Because………….
the mass of the moon is so much smaller than the mass of the Earth! Because of this, the moon exerts much less gravitational force on you.
Units of MassTo measure the properties of matter, scientists
use a system called the International System of Units.
Also known as… “SI” (because of its French name, Système International)
UnitsThe SI unit of mass is the kilogram (kg).
If you weigh 90 pounds on Earth, your mass is about 40 kilograms.
A smaller unit that is also used is the gram (g).
How many grams are in a kilogram?
1000
Why do scientists prefer to describe matter by
its mass?Unlike weight, mass does not change with location, even
when the force of gravity on an object changes.
VolumeAll matter has mass and takes up space… right?
RIGHT!
The actual amount of space that matter occupies is
called its volume.
Units of Volume
Common units of volume include…*liter (L)*milliliter (mL)*cubic centimeter (cm3)
Units of Volume1 L = 1,000 mL1 mL = 0.001 L1 mL = 1 cm3
Calculating VolumeVolume of solid objects = cubic centimeters (cm3)
[usually]
Volume = Length x Width x Height
5 cm20 cm
9 cm
What is the volume of this brick?900 cm3
How could you measure the volume of an apple?
Submerge the apple in water in a graduated cylinder. The water level will rise by an amount that is equal to the volume of the object in milliliters.
Density• Samples of two different materials may have
the same volume, but they don’t necessarily have the same mass.
A kilogram of
sand takes up
much less space
than a kilogram
of feathers.
The volumes differ because sand and feathers have different densities.
Density relates the mass of a material in a given volume.
This is often expressed as the number of grams in one cubic centimeter.
For example, the density of water at room temperature is expressed as “one gram per cubic centimeter (cm3).”
Every gram of water has a volume of 1 cm3
Math in Science?!
Density = mass . volume
This bar (between the ‘g’ and the ‘cm3’) tells you that you can determine the density of a sample of matter by dividing its mass by its volume
1 g/cm3
Sinking or Floating?
Imagine you have a solid block of wood and a solid block of iron. You drop both into a tub of water. Do they float? Do they sink? What happens?Wood floats! (think of a boat…)
Iron sinks! (think of an anchor…)
Objects with _______________ densities than water will sink.
Objects with _______________ densities than water will float.
lesser
greater
Using Density
Density is a _____________ property of a substance. (physical or chemical??)
Because of this, density can be used to __________ an ____________substance.
physical
identify unknown
Imagine you are out hiking, and you find a shiny, golden-colored rock. How would you know the
rock is gold or fool’s gold?
• Look up the _________________ of gold.
• Measure the ________________ and __________________ of the rock to find its ________________.
• If the ______________ matches the amount that you looked up, you have a match!
Happy October!Happy October!Monday October 1, 2012
• Calculate your weight as it would be on the moon.
– Your weight would be only one sixth (.167) of your weight on Earth.