Chem 1A General Chemistry Chapter 1 Keys to the Study of Chemistry Dr. Orlando E. Raola FALL 2012 1/1
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Chem 1AGeneral Chemistry
Chapter 1Keys to the Study of Chemistry
Dr. Orlando E. Raola
FALL 2012
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Overview
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Chemistry
Chemistry is the study of matter, itsproperties, the changes that matterundergoes, and the energyassociated with these changes.
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Matter and Energy
Matter anything that has both mass and volume – the “stuff” ofthe universe: books, planets, trees, professors, students.
Composition the types and amounts of simpler substances thatmake up a sample of matter
Properties the characteristics that give each substance a uniqueidentity
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Matter and Energy
Matter anything that has both mass and volume – the “stuff” ofthe universe: books, planets, trees, professors, students.
Composition the types and amounts of simpler substances thatmake up a sample of matter
Properties the characteristics that give each substance a uniqueidentity
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Matter and Energy
Matter anything that has both mass and volume – the “stuff” ofthe universe: books, planets, trees, professors, students.
Composition the types and amounts of simpler substances thatmake up a sample of matter
Properties the characteristics that give each substance a uniqueidentity
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Physical and Chemical Properties
Physical Properties
properties a substance shows byitself without interacting withanother substance- color, melting point, boiling point,density
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Physical and Chemical Properties
Physical Properties
properties a substance shows byitself without interacting withanother substance- color, melting point, boiling point,density
Chemical Properties
properties a substance shows as itinteracts with, or transforms into,other substances- flammability, corrosiveness
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The distinction betweenphysical and chemical change
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Problem
We can use visualizations to help us understand the nature of thechanges in matter. Is the change depicted chemical or physical?
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The States of Matter
A solid has a fixed shape and volume. Solids may be hard or soft,rigid or flexible.A liquid has a varying shape that conforms to the shape of thecontainer, but a fixed volume. A liquid has an upper surface.A gas has no fixed shape or volume and therefore does not have asurface.
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The Pysical States of Matter
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Temperature and Change of State
• A change of state is a physical change. - Physical form changes,composition does not.
• Changes in physical state are reversible - by changing thetemperature.
• A chemical change cannot simply be reversed by a change intemperature.
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Temperature and Change of State
• A change of state is a physical change. - Physical form changes,composition does not.
• Changes in physical state are reversible - by changing thetemperature.
• A chemical change cannot simply be reversed by a change intemperature.
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Temperature and Change of State
• A change of state is a physical change. - Physical form changes,composition does not.
• Changes in physical state are reversible - by changing thetemperature.
• A chemical change cannot simply be reversed by a change intemperature.
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Energy in Chemistry
• Energy is the ability to do work.• Potential Energy is energy due to the position of an object.• Kinetic Energy is energy due to the movement of an object.• Total Energy = Potential Energy + Kinetic Energy
Etot = Ekinetic + Epotential
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Energy in Chemistry
• Energy is the ability to do work.• Potential Energy is energy due to the position of an object.• Kinetic Energy is energy due to the movement of an object.• Total Energy = Potential Energy + Kinetic Energy
Etot = Ekinetic + Epotential
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Energy in Chemistry
• Energy is the ability to do work.• Potential Energy is energy due to the position of an object.• Kinetic Energy is energy due to the movement of an object.• Total Energy = Potential Energy + Kinetic Energy
Etot = Ekinetic + Epotential
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Energy in Chemistry
• Energy is the ability to do work.• Potential Energy is energy due to the position of an object.• Kinetic Energy is energy due to the movement of an object.• Total Energy = Potential Energy + Kinetic Energy
Etot = Ekinetic + Epotential
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The scientific approach to understanding nature
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Units and Conversion Factors
The results of measurements are always expressed as the productof a pure number and a unit of measure.
length = 4.5 m
Conversion Factors allow us to express a quantity with differentunits.
body mass = 190.2 lb × 1 kg2.205 lb
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Units and Conversion Factors
The results of measurements are always expressed as the productof a pure number and a unit of measure.
length = 4.5 m
Conversion Factors allow us to express a quantity with differentunits.
body mass = 190.2 ��lb × 1 kg2.205 ��lb
= 86.26 kg
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The SI is the System Used in Scientific Work
Fundamental SI UnitsFundamental Quantity Unit Symbollength meter mmass kilogram kgtime second sthermodynamic temperature kelvin Kamount of substance mole molelectric current ampere Aluminous intensity candela cd
All other units are derived from the fundamental units:
Area m2
Volume m3
Density kg·m−3
Velocity m·s−1
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Unit Conversions
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