Download - Chemistry Unit 2 Part 1
Matter and Change
Part 1 – Properties of Matter
TAKS student expectation
• Integrated Physics and Chemistry (8) Science Concepts. The student knows that changes in matter affect everyday life. The student is expected to:– (A) distinguish between physical and
chemical changes in matter such as oxidation, digestion, changes in states, and stages in the rock cycle; and
Here’s what you have to do if you want to pass this part of
the TAKS:
1. Distinguish between physical and chemical properties.
Here’s what you have to do if you want to pass this part of
the TAKS:
1. Distinguish between physical and chemical properties.
Characteristics of a substance can be classified as physical properties or chemical properties. Which of the following is a chemical property?A Boils at 56ºCB Tastes sourC Has a density of 2.9 g/cm3D Reacts with acid to produce hydrogen gas
Sample Question
Source: Reviewing Chemistry TAKS.
Properties and Changes in Matter
• Every substance has characteristic properties.
• Chemists use these properties to distinguish between substances and separate them.
Extensive vs. IntensiveProperties
Properties are either extensive or intensive.
Extensive Properties
depend on amount of matter present
volume, mass, and
amount of energy in a substance
Intensive Properties
do not depend on amount of matter
presentmelting point, density,
ability to conduct electricity, and percent
composition
Properties of One Penny
Properties• Metal
• Composed of 2.5% copper and 97.5% zinc
• Mass – 2.50 grams
• Volume – 0.442 mL
• Density – 5.66 g/mL
Properties of Many PenniesProperties• Metal
• Composed of 2.5% copper and 97.5% zinc
• Mass – 2500 grams(1000 pennies x 2.5 g)
• Volume – 442 mL(1000 pennies x.442mL)
• Density – 5.66 g/mL
One Thousand Pennies
Extensive vs. Intensive Properties
WHICH PROPERTIES REMAINED THE SAME?
• Metal
• Percent Composition
• Density
The intensive properties remained the same because they do not depend on
the amount of pennies present.
Extensive vs. Intensive Properties
WHICH PROPERTIES CHANGED?• Mass
• Volume
The extensive properties changed because they do depend on the amount of pennies present.
Property Types• There are 2 major categories
that all properties of matter fall into
Physical Properties
Physical properties are characteristics that can be observed or measured without changing the identity of a substance.
They can be observed by using the five senses.
Physical Properties• Cross between a lab
and a poodle
• Size of a lab
• With the curly hair of a poodle
• Can be black, yellow, brown, or white
• Tail of a lab
What are What are the the
physical physical properties properties
of a of a labradoodlelabradoodle
??
Chemical PropertiesChemical properties relate to a
substance’s ability to undergo changes that transform it into different
substances.
Examples of chemical properties:
Conductivity -ability to conduct electricity
Flammability – ability to ignite
Electronegativity – the ability to retain electrons
Density – a Property of Matter
Density – a ratio that compares the mass of an object to its volume.
The density of every pure substance in the world is unique.
Calculating Density
The formula for calculating
density is given on your TAKS formula chart,
so you must know how to use
it
Vm
D
volume
massDensity
Sample Question
Source: Grade 11 TAKS Information Book
Sample Question
Source: Spring 2003 Exit TAKS
Sample Question
Source: Spring 2003 Exit TAKS
Sample Question
Source: Spring 2003 Exit TAKS
Sample Question
Source: Spring 2003 Exit TAKS
Sample Question
Source: Spring 2003 Exit TAKS
Sample Question
Source: Spring 2003 Exit TAKS
Remember to duplicate
Sample Question
Source: Spring 2003 Exit TAKS
Sample Question
Source: Spring 2003 Exit TAKS
Sample Question
Source: Spring 2006 10th TAKS
Sample Question
Source: Spring 2006 10th TAKS
Part 2 – Changes in Matter
Physical ChangeA change in the physical appearance of a
substance that does not change the identity of the substance.
LIQUID
SOLID
GAS
Physical ChangesPhase Change – physical change from
one state to another
LIQUIDBetween 0°C and
100 0°C
SOLIDBelow 0°C
GASAbove 100°C
Only the temperature changes
Still H2O in every form!!!
Physical Changes• Examples of physical changes:
Crushing an aluminum can
Cutting your hair
Shredding paper
Chemical ChangesChemical changes, or chemical reactions, occur
when one or more substances is converted into another substance.
Original atoms are preserved
New substances are formed
Different chemical composition than original substance
Chemical ChangesChemical changes are chemical reactions.
Indicated by a number of signs
• formation of a gas,
• formation of a solid, or precipitate
• change in temperature
• evolution of heat and light
• Change in color
• Change in odor
Chemical Changes• When iron (Fe) rusts, you can see it
happen over a long period of time.
• The actual iron molecules change their structure as they react with oxygen and are oxidized.
Chemical Changes• Examples of chemical changes:
Milk souring
Grass growing
Frying an egg
Energy Transfer• All changes (physical and chemical) involve some
transfer of energy.
• Body uses energy from chemical reactions to digest food.
• Weather involves a transfer of energy to evaporate water in the atmosphere.
• Therefore, the study of matter also involves the study of energy.
Summary• Extensive Properties
• Intensive Properties
• Physical Properties and Changes
• Chemical Properties and Changes
• Transfer of Energy