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 C C C Carbon Atoms

Elements  Element: pure substance made of only 1 kind of atom Carbon Oxygen 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!!!!!