Classifying Matter CHAPTER 2

Matter: substance that has mass and takes up space What is matter? Matter: substance that has mass and takes up space

States of Matter Phase Volume Shape Structure SOLID LIQUID GAS PLASMA Definite Definite Definite Indefinite Indefinite Indefinite Indefinite Indefinite Draw an arrow next to the table above in the order of increasing energy.

Three States of Matter Plasma

Water in Three States Remember, because of the arrangement of the particles liquid water is more dense than solid water (ice)

Phase Changes

Sublimation Melting Boiling Freezing Condensation Deposition Phase Changes Sublimation Melting Boiling liquid gas solid Freezing Condensation Deposition

Phase Diagrams phase diagram: graph that shows the relationship between phase of matter and the temperature and pressure of the substance. Used to identify boiling point/freezing point at any pressure

Three Imporant Lines Liquid-gas phase changes: Liquid-solid phase changes: Solid-gas phase changes:

Two Important Points Triple Point: where all three lines meet, a specific temperature and pressure where all three phases exist at the same time

Triple Point Video

Two Important Points Critical Point: a specific temperature and pressure where the gas can no longer be turned into a liquid, above this point a substance becomes a supercritical fluid

“Normal” Conditions Occur at standard atmospheric pressure: 1 atm or 101.3 kPa To identify the normal boiling point of a substance: Locate the line between liquid and gas, and identify the temperature at 101 kPa __________________ To identify the normal freezing point of a substance: Locate the line between liquid and solid, and identify the temperature at 101 kPa __________________

Practice

Classifying Matter

Matter Pure Substance -definite composition -cannot be physically separated Element -one type of atom Compound -two or more types of atoms chemically bonded Mixture -two or more varying parts -can be physically separated Homogeneous -evenly distributed -uniform properties Solution -very small particles -light passes through Heterogeneous -unevenly distributed -varying composition Suspension -large visible particles -particles settle out -blocks light Colloid -unevenly suspended particles -shows a visible beam of light (positive Tyndall Effect)

How do you classify matter? If it is a pure substance: fixed composition exact chemical formula If it is a mixture: varying composition combined physically can be separated physically

How do you know if something is an element? chemical formula shows only one type of atom How do you know if something is a compound? chemical formula shows two or more elements combined

Homogeneous OR Heterogeneous? Homogenous mixture – composition of the mixture is the same throughout. Examples: soda, KoolAid Heterogeneous mixture – composition is unevenly distributed throughout. Examples: cookie dough ice cream, iron filings in sand

Tyndall Effect Scattering of light beam caused by the reflection from suspended particle If the light passes through the mixture with no visible beam, then the mixture is a SOLUTION If a mixture settles out and blocks the light, then it is a SUSPENSION If a mixture does not settle and shows a beam of light through it (positive tyndall effect), then it is a COLLOID

How do you know if it is a Solution? Uniformly Mixed One substance is dissolved in another solute: part of the mixture that gets dissolved solvent: part of the mixture that does the dissolving Tyndall Effect:

How do you know if it is a Suspension? Particles settle out Tyndall Effect:

How do you know if it is a Colloid? Particles unevenly distributed throughout Shows a beam of light Tyndall Effect:

Hom/Het? Soln/Susp/Coll? Fog ____________ ___________ Paint ____________ _________ Syrup ____________ ___________ Colloid: yogurt

Particle View of Matter

Draw particles on note sheet.

Examples

Methods of Separation

Physical means: it can be separated into its pure components. magnet

Methods of Separation Techniques: Evaporation Strainer Centrifuge PASTA/WATER SAND/IRON FILINGS Techniques: Strainer Filtration Physical SALT /WATER SAND/WATER Evaporation Centrifuge Distillation BLOOD FOOD COLORING/WATER Switch examples! Centrifuge – washing machine

The Distillation Set Up

Petroleum Refining What is Petroleum? Pumped from underground Known as crude oil or “black gold” Greenish-brown to black color Thin as water or thick as soft tar Made up of HYDROCARBONS (compounds made of Hydrogen and Carbon atoms ONLY) Can be separated using FRACTIONAL DISTILLATION

The separation of liquid substances according to their differing boiling points is called distillation.

Distillation Animation During distillation, the vaporized molecules move upward in the distilling column. The smaller, lighter molecules have the lowest boiling points and either condense high in the column or drawn off the top of the tower as gases. Distillation Animation

PHYSICAL AND CHEMICAL CHANGES

Physical Properties and Changes physical property: characteristic that can be observed or measured without changing the identity of the substance. melting point, boiling point, density physical change: change in a substance that does not involve a change in the identity of the substance. dissolving, cutting, melting, and boiling

Chemical Properties and Changes chemical property: a substance’s ability to undergo changes that transform it into different substances Example: combustibility, reactivity chemical change: change in which one or more substances are converted into different substance Example: rusting, cooking food

Evidence of a Chemical Change Color change Temperature change Production of a gas Change in odor Formation of a precipitate Precipitate: insoluble solid that separates out of solution

Solubility and Phase changes are PHYSICAL!!!! NOTE: Solubility and Phase changes are PHYSICAL!!!!