Matter and Energy

Physical States of Matter

Property Solid Liquid Gas

Shape definite indefinite indefinite

Volume fixed fixed variable

Compressibility negligible negligible significant

Property

of particles Solid Liquid Gas

Kinetic energy very low high very high

Movement none restricted unrestricted

As temperature increases, a solid melts to a liquid, and then the liquid vaporizes to a gas.

Sublimation – A direct change from a solid state to a gas.

As temperature decreases, a gas condenses to a liquid, and then the liquid freezes to a solid.

Deposition – A direct change of state from a gas to a solid.

A heterogeneous mixture is non-uniform and its properties vary throughout the sample.

A heterogeneous mixture can be separated into two or more homogeneous substances by physical methods

A homogeneous mixture is uniform and its properties are uniform throughout the sample

A homogeneous mixture contains two or more substances and can be separated by physical methods.

A pure substance is matter that has definite composition and constant properties.

A compound has definite composition and constant properties, but can be broken down into elements by a chemical change.

An element is a substance that cannot be broken down further by an ordinary chemical change.

An element is a pure substance that cannot be broken down further and still maintain its unique properties.

Element Mass Percent

Oxygen 49.5%

Silicon 25.7%

Aluminum 7.5%

Iron 4.7%

Calcium 3.4%

Sodium 2.6%

Potassium 2.4%

Magnesium 1.9%

Hydrogen 0.9%

Titanium 0.6%

All other elements 0.5%

In 1803, the English chemist John Dalton proposed that elements are composed of indivisible , spherical particles. (Atomic theory)

Dalton called one of these individual particles an atom, from the Greek atomos meaning indivisible.

In 1818, the Swedish chemist J. J. Berzelius proposed our current system of symbols for the element. Where a symbol corresponds to the first letter of the name of that element. For elements that start with the same letter, two letters are used. Co, Ca, Cs, Cr, Cl

(what is CO?)

The names of the elements are derived from various sources.

Greek hydrogen hydro (water)

Latin carbon carbo (coal)

lead Pb plumbum

Iron Fe ferrous

Copper Cu cuprous

Region of discovery

germanium from Germany

scandium from Sandinavia

Property Metals Nonmetals

Physical state solid solid, gas

Appearance metallic luster dull

Pliability malleable, ductile brittle

Conductivity heat, electricity nonconductor

Density usually high usually low

Melting point usually high usually low

Chemical

reactivity react w/ nonmetals react w/ metals

and nonmetals

Law of definite composition – Compounds always contain the same elements in a constant proportion by mass.

Sodium chloride, NaCl, table salt, contains sodium and chlorine in a constant proportion by mass. 39.3% sodium and 60.7% chlorine.

Water, H2O, contains 11.2% hydrogen and 88.8% oxygen by mass. Or 2 g hydrogen and 16 g oxygen.

Molecule – More than one atom bonded to an another. Most compounds are molecules.

Diatomic elements are not compounds.

( H₂ N₂ O₂ Fl₂ Cl₂ Br₂ I₂)

A physical property refers to those characteristics of a substance we can observe without changing the composition of the substance.

appearance

melting and boiling point

density

heat and electrical conductivity

solubility

A chemical property of a substance describes its chemical reactions with other substances.

In a physical change, the chemical composition does not change.

In a chemical change, the composition of the sample changes, and a new set of properties are observed.

In a chemical change, we usually observe one of the following:

Family Reactions

Group IA with oxygen with water with HCl

lithium Li₂O H₂ + LiOH H₂ + LiCl

sodium Na₂O H₂ +NaOH H₂ + NaCl

potassium K₂O H₂+KOH H₂ + KCl

Group II A

calcium CaO H₂+Ca(OH)₂ H₂+ CaCl₂

strontium SrO H₂+Sr(OH)2 H₂+SrCl₂

barium BaO H₂+ Ba(OH)2 H₂+BaCl₂

Group IVA

carbon CO₂ NR NR

silicon SiO₂ NR NR

p113

In 1789, Antoine Lavoisier announced the conservation of mass principle.

Through experiments, Lavoisier found that the mass of substances before a chemical change was always equal to the mass of substances after the reaction.

This is know as the of conservation of mass law.

Types of Energy

Potential energy is stored energy that matter possesses as result of its position or composition

Kinetic energy is energy matter has as a result of its motion.

The total mass and energy in the universe is constant.

Energy and mass can neither be created or destroyed.