Chapter 2: Chapter 2: Matter and How It Matter and How It

Can ChangeCan Change

Properties of MatterProperties of MatterEverything is made of matterMass is the amount of matter (grams or kg)Volume is the space that the matter takes up (cm)Two main types of properties:

Physical properties: A characteristic of a substance that can be measured or observed without changing the substance’s composition

Intensive-don’t change for a particular sample such as density, melting point, boiling point, color, solubility conductivity, ductility, and specific heat. Extensive- depend on size of matter such as length, mass, height, volume, and area.

Chemical properties: A characteristic of a substance that describes how it interacts with other substances to become something new.

Changes in MatterChanges in Matter

Physical Change– An alteration of matter that does not change the

chemical composition of the material – For example: freezing or melting, boiling or

condensing, cutting, grinding, bending, blending

Chemical Changes– Results in a change in the chemical composition

of the substance(s) which is called a reaction. – For example: rusting, composting, tarnishing

Practice Identifying Types of Practice Identifying Types of Changes in MatterChanges in Matter

Physical

Physical

Physical

Physical

Chemical

Chemical

Chemical

Chemical

Chemical ReactionsChemical ReactionsIn a chemical reaction, one or more substances change into new substances by rearranging the atoms

• Copper + nitric acid copper(II) nitrate + nitrogen dioxide + water

Reactants Products

The ability of a substance to undergo a chemical reaction and form new substances is called a chemical property.How to tell a chemical reaction has occurred. – Heat is absorbed or given off.– Change in color or odor.– Production of a gas or solid.

Law of Conservation of Mass– During any chemical reaction, mass is neither created nor destroyed.

The total mass of the system (products plus reactants) and the mass of each element is unchanged.

Chemical Reaction Movies

States of MatterStates of MatterSolid~

– Definite shape and volume– Very slight thermal expansion and almost incompressible – Divided into subclasses of amorphous (or glassy) solids and

crystalline solids • Arrangements of atoms or molecules in crystalline solids are repeated

regularly over a very long range of millions of atoms • Arrangements in amorphous solids are somewhat random or short range

of say some tens or hundreds of atoms.

Liquid~– Indefinite shape (flows) and definite volume– Moderate thermal expansion and almost incompressible

Gas (Vapor)~– Indefinite shape and indefinite volume– Great thermal expansion and readily compressible– A vapor is the gaseous form of a substance that is normally solid or

liquid at room temperature

Plasma~ – A very hot state of matter where atoms have been ripped apart into

their smaller parts, protons and electrons.

Animation

Types of MatterTypes of MatterSubstances: contains only one type of matter and has a uniform and definite composition

Element~ – Composed of just one type of atom. They cannot be

separated into simpler substances using chemical means.– They are represented by a chemical symbol (see Periodic

Table).– For example: Gold (Au), Iron (Fe), Oxygen (O or O2)

Compound~– Substances composed of two or more different kinds of

atoms. The atoms are chemically combined to form a molecule (or formula unit).

– They are represented by a chemical formula which shows the elements and relative number of atoms in the compound.

– For example: Water, H2O and Salt, NaCl.

Types of MatterTypes of MatterMixtures: a physical blend of two or more substances.

Homogenous~ – Transparent, uniform in composition, also called

solutions. – Can be separated by distillation, ion exchange, reverse

osmosis– For example: Koolaid, salt water, and air

Heterogeneous~– Opaque, not uniform in composition and appearance– Can be separated by sieving , tweezing and skimming– For example: Milk, sand, bronze and blood