Chapter 3

Matter & Its Properties

Volume and Mass

Volume: amount of 3-D space an object occupies; all matter has volume

Mass: measure of the amount of matter; measure with a balance

Matter

Matter: anything that has mass and takes up space

Basic Building Blocks of Matter

Atom: smallest unit of an element that maintains the properties of that element

CC

CCarbon Atoms

Elements

Element: pure substance made of only 1 kind of atom

CarbonOxygen

DIATOMIC

MONATOMIC

Compound

Compound: substance made from the atoms of two or more elements chemically bonded

Water

Properties

Chemists use properties to distinguish between substances and to separate them.

Properties

Entire group of substances: example – metals’ distinguishing property is conductivity

Unknown substance conducts electricity well – probably a metal

Properties

Subgroups of substances: Sugars can be reducing or nonreducing

Something called Fehling’s solution can be used to test the sugar

Extensive Properties

Depend on the amount of substance present

Examples: mass, volume, amount of energy in a substance

Intensive Properties

Do not depend on the amount of matter present (independent)

Examples: melting point, boiling point, density, ability to conduct electricity and heat

Intensive vs. Extensive

Imagine heating 100 mL and 400 mL of water, respectively

Boiling point? Heat absorbed? Time to boil?

Physical Property

Physical Property: characteristic can be observed or measured without changing the identity of the substance

Example: melting or boiling point; color, size, etc.

Physical Change

Physical Change: change in a substance that does not involve a change in the identity of the substance

Example: grinding, cutting, melting, etc.

Special Physical Changes: CHANGES OF STATE

Changes of State: special physical changes in which a substance changes from one state to another

The 3 common states are solid, liquid, and gas

SOLID

Solid: 1. definite volume and shape

2. particles packed together in fixed positions

3. particles vibrate about a fixed position

LIQUID

Liquid: 1. definite volume but indefinite shape 2. takes shape of container 3. particles close but flow around one another

GAS

Gas: 1. no definite shape or volume 2. particles a great distance from each other

SOLIDS, LIQUIDS, & GASES

Change of State Processes

Solid to Liquid: Liquid to Gas: Gas to Liquid: Liquid to Solid: Solid to Gas: Gas to Solid:

Chemical Property

Chemical property relates to a substance’s ability to undergo changes that transform it into different substances

Ex: iron rusting, silver tarnishing, match burning, etc.

Chemical Change/Reaction

Chemical change or chemical reaction: change in which one or more substances are converted into different substances

Chemical Equations

Reactants: substances that react in a chemical change (left side of chemical equation)

Products: substances that are formed in a chemical change (right side of chemical equation)

Reactants Products

Law of Conservation of Matter

(Add this to outline) In a chemical reaction, matter cannot

be lost nor gained.

Matter may rearrange but cannot be created nor destroyed.

Mass of reactants = mass of products

Evidence of chemical change

(Add this to outline) Ideas?

Energy and Changes in Matter

Energy is involved in both physical and chemical changes.

Different forms include heat and light.

Energy

Uses include: 1. provide energy for a physical change (i.e. melting) 2. provide energy for a chemical

change (i.e. decomposition of water)

Energy

Energy in physical and chemical changes may be released or absorbed, but it is not created or destroyed! Law of Conservation of Energy

Classification of Matter

All matter can be classified as:1. pure substances OR

2. mixtures

Mixtures

Mixtures: (def.) blend of two or more kinds of matter, each of which retains its own properties and identity

Mixtures

Properties of a Mixture: are a combination of the properties of its components

Composition of a Mixture: must be specified (in a % of mass or volume)

Homogeneous v. Heterogeneous

Homogeneous: uniform in composition; same proportion of components throughout (ex. Salt water solution)

Heterogeneous: not uniform throughout (ex. Mixture of clay and water)

Separating Mixtures

1. Filtration

2. Paper Chromatography

3. Centrifuge

Pure Substances

Pure substances: (def.) has a fixed composition and differs from a mixture in the following ways:

Pure Substances

1. Every sample of a given pure substance has exactly the same characteristic properties

(unlike mixtures whose properties depend upon the relative amounts of mixture’s components)

Pure Substances

2. Every sample of a given pure substance has exactly the same composition

Ex. All pure water is always 11.2% H and 88.8% O by mass.

Pure Substance Examples

Water

Sucrose

Pure substances are compounds or elements

Laboratory Chemicals and Purity

Chemicals in lab treated like pure chemicals BUT all have some impurities

Impurities can sometimes affect the results of a reaction

The End of Section 1-2!!!!!