5.1 Classification Of Matter Part B

TABLE OF CONTENTS
PHYSICAL PROPERTIES OF MATTER 1-16
Density 7-10
PRACTICE PROBLEMS #1 11
PRACTICE PROBLEMS #3 14-15
REVIEW 16-17
CHEMICAL PROPERTIES OF MATTER 18-22

MATTER PART II PROPERTIES OF MATTER

Matter Pure Substances Mixtures Elements Compounds Homogeneous Heterogeneous He, O H 2 O, NaCl Tea, kool-aid Rocky Road ice cream, muddy water REMEMBER THIS ? This system allows us to classify matter into general types.

PROPERTIES OF MATTER are sets of characteristics by which a substance is recognized. However, we can also describe matter by its chemical and physical properties , referred to generally as properties of matter . How can we recognize physical properties? Physical properties are those that we can determine without changing the identity of the substance we are studying.

Mass – amount of matter that something has.
Volume – amount of space that something takes.
State of matter – physical forms in which a substance can exist. Solid, liquid, gas, plasma.
Melting point – temperature at which a substance changes from solid to liquid.
Boiling point – temperature at which a substance changes from liquid to gas.
Freezing point – temperature at which a substance changes from liquid to solid.
Density – the mass of a substance compared to its volume d =
Malleability – the ability to be hammered or beaten into thin sheets, to bend and not break.
Electrical conductivity – the ability to carry electricity.
Ductility – the ability to be drawn into thin wire.
EXAMPLES OF PHYSICAL PROPERTIES m v

Changing from solid to liquid to gas does not change the composition of water. It is still H 2 O. MORE CLUES ON PHYSICAL PROPERTIES Breaking the object changes the mass, volume and shape. But the basic composition is still the same. The spoons ability to bend without breaking, called malleability, is a physical property. Despite a change in its shape, the spoon is still a spoon, although admittedly not as useful.

Density, an important physical property
Density is a comparison of how much matter there is in a certain amount of space.
Which one is more dense? Now which one is more dense?

What is density?
Density = mass OR mass ÷ volume.
volume
Units for density: _ g_
cm 3
Why are these the units for density?
Mass is measured in grams
Volume is measured in cm 3 (solids) or mL (liquids)
ALWAYS REMEMBER UNITS! If asked whether a basketball or a bowling ball of the same size was more dense, you would know the answer. Sometimes, however, it isn’t so easy to determine density. Density can be determined quantitatively using the following equation.

Density Shortcut M D V ass ensity olume D = M V M = D x V V = M D If you need mass, the triangle method shows that to solve you multiply D x V. If you need density, what is left is m/v If you need volume, what is left is m/D

Let’s try a density problem together
Frank has a paper clip. It has a mass of 9g and a volume of 3cm 3 . What is its density?
Frank also has an eraser. It has a mass of 3g, and a volume of 1cm 3 . What is its density? Mass = 9g Volume = 3cm 3 Density = ? Equation D = m ÷v D = 9g/3cm 3 D = 3 g/cm 3 D = m/v D = 3g/1cm 3 = 3g/cm 3

DENSITY PRACTICE PROBLEMS #1 Work on these problems
Jack has a rock. The rock has a mass of 6g and a volume of 3cm 3 . What is the density of the rock?
Jill has a gel pen. The gel pen has a mass of 8g and a volume of 2cm 3 . What is the density of the rock?
Answer: 3g/cm 3 and 4g/cm 3

DENSITY PRACTICE PROBLEMS # 2 Now try these
Al’Licia has a watch. It has a mass of 4g and a volume of 2cm 3 . What is the density of the watch?
Mia has a wallet. It has a mass of 15g and a volume of 5cm 3 . What is the density of the wallet?
Answer: 2g/cm 3 and 3g/cm 3

Super Scientist Question of the Day
Jake has a book, a ruler, and a balance.
How can Jake find the density of the book with the tools he has?
Measure the book, length x width x height. This gives volume in cm 3 . Then measure the mass of the book on a balance. This gives the mass in grams. Plug in measured mass for m, and measured volume for v and solve for density.

Reviewing Density Liquid Layers
Which layer has the highest density?
Which layer has the lowest density?
Imagine that the liquids have the following densities:
10g/cm 3 . 3g/cm 3 .
6g/cm 3 . 5g/cm 3 .
Which number would go with which layer?

Liquid Layers
Imagine that the liquids on the right have the following densities:
15g/cm 3 10g/cm 3
3g/cm 3 9g/cm 3
7g/cm 3 12g/cm 3
Match the colors to the correct densities.
3g/cm 3 7g/cm 3 9g/cm 3 10g/cm 3 12g/cm 3 15g/cm 3

Review
What is the formula for density?
What happens if you pour together liquids that have different densities?
Will the liquid on the top have the highest or lowest density?
Will the liquid on the bottom have the highest or lowest density?

EXPLAIN THIS! Image courtesy of Texarkana Science Club, Texas A&M University Regular coke is made with sugar, diet coke has a sugar substitute which is far less dense than sugar. The result is that diet coke is less dense than water and floats. At your next family reunion dig down in the cooler…you’ll find that coke at the bottom.

How can we recognize chemical properties? Example: Hydrogen has the potential to ignite and explode, as it did here with the Hindenburg. http:// www.americanrhetoric.com/speeches/hindenburgcrash.htm Chemical properties describe the way a substance can change or react to form other substances.

More clues on chemical properties Rusting is a chemical property. In the presence of oxygen and with a little help from moisture, metals rust. Layer by layer the metal atoms combine with oxygen to form a brand new substance. Flammability is a chemical property. Childrens toys, clothing, and bedding are all items that have special guidelines that manufacturers must follow concerning the flammability of their materials.

CHEMICAL CHANGE CLUES
Recognizing chemical changes is an important EOC concept. There are a few easy clues for recognizing these changes :
1 st – NEW SUBSTANCE FORMED. This is the most basic, bottom line evidence. Brand new stuff, different from the original. 2 nd – GAS FORMED. Usually seen as bubbles when two substance are mixed. Think volcano experiment with baking soda and vinegar. Don’t mistake boiling as a chemical change however. 3 rd – ENERGY PRODUCED. In other words, heat, light, sound given off. Example: candle, fireworks, etc. 4 th – PRECIPITATE FORMED. This means that when you mix two liquids a solid is formed in the solution. 5 th – CHANGE IN COLOR. The key is that it is a CHANGE in color. Red food coloring in water produces red water. This is not a change in color, therefore not a chemical change.

Comparison of Physical and Chemical Properties

The formation of a mixture The formation of a compound Chemical Change Physical Change

How would you classify these properties? Ask yourself…does changing this change the makeup of the substance?
Volume P C
Luster P C
Electrical conductivity P C
Flammability P C
Color P C
Density P C
Rusting P C
Practice Problems

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5.1 Classification Of Matter Part B

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