Chapter 2

Energy and Matter

Energy

Kinetic Potential

Measuring Energy

Calorie = food calorie1 Cal = 1 cal Amount of heat needed to raise 1 g of water 1oCJoule SI unit

Law of Conservation of Energy

Practice

Convert 300.0 J to calConvert 433.2 cal to JoulesConvert 2500.0 Cal to Joules

Temperature

Scale of Amount of heat (energy, molecular movement) in somethingScales

Kelvin absolute 0

Celsius bp, mp of water

Fahrenheit is wacky

Heat Flow

In what direction does heat flow?From hot things to cold things From cold things to hot things

Do hot/cold hands demo

Conversions

oC to oF

oC to K

Matter

Defined:

States of Matter

Solid

Liquid

States of matter

Gas

Plasma

Blow up a balloon?

Properties

Physical Properties

Chemical Properties

Changes in Matter

Physical ChangesChanges in

Changes in Matter

Chemical ChangesChanges in

Law of Conservation of Mass

Mass can be

The total mass

Pure Substances

ElementA substance that cannot be separated into simpler substances

Elements

~111 presently known elementsBuilding blocks of all substancesAt room temperature: Figure 3.3 distribution of elements in galaxies, earths crust, seawater and air, and human bodies

Elements

Names of the elementsGreekLatinGermanProperties of elementsScientist who discovered itLocation where discovered

Elements

Arranged in the Periodic Table (inside front cover)SymbolsOne or two lettersUsually part of name Some symbols are Latin/Greek name

Elements

ClassificationMetalNonmetalMetalloidSee Table 3.5 (page 54)

Metals left side (not Hydrogen)

Nonmetals Right Side

Metalloids _ B, Si, Ge, As (Arsenic), Sb (Antimony), Te (Tellurium), Po (Polonium)

Elements

Metals:Usually Good High High Usually dont combine with each otherReadily combine with nonmetals

Elements

Nonmetals:Solids (C, P, S, Se, I); Liquid (Br); Gases (all others) Will combine with each other Will combine with metals or metalloidsSome found uncombined in nature (noble gases)

Elements

MetalloidsHave properties of

Some used for semiconductors in electronics

Pure Substances II

CompoundTwo or more elements

Compounds

Two or more elements chemically combinedNew properties Can be

Compounds

MolecularHeld together with Molecule:

Water is an example

Compounds

IonicIon:

Cation Anion Held together by ionic bond

Compounds

Diatomic MoleculesAlways only 7 naturally occurring

Substances and Mixtures

Pure Substance: a particular kind of matter with a Mixture: Not chemically combined

Matter

Pure substances (homogeneous composition)

Mixtures of two or more substances

Elements

Compounds

Solutions (homogeneous composition one phase)

Heterogeneous mixtures (two or more phases)

Figure 3.2 (page 48)

Types of Mixtures

Heterogeneous mixtures

Book describes homogeneous and heterogeneous as applying to pure substances AND mixtures but MOST COMMONLY used with mixtures

Types of Mixtures

Homogeneous mixtures

Separating Mixtures

Do NOT cause chemical changesHeterogeneous Mixtures

Separating Mixtures

Homogeneous Mixtures

Separating Mixtures

Homogeneous Mixtures

Separating Mixtures

Homogeneous Mixtures