matter & its properties

MODERN CHEMISTRY TEXTBOOK: CH. 1

Matter & Its Properties

Basic Building Blocks of Matter

• Anything that takes up space and has mass• Takes up space volume• Certain amount of stuff mass

• How does one make stuff?• Start with the ATOM!

What is matter?

• The study of matter and the changes it undergoes• Composition• Structure• Properties• Energy changes

What is chemistry?

• Atom – smallest unit of an element that has the chemical identify of that element

• Element – Pure substance that cannot be broken down into simpler, stable substances• So only 1 kind of atom (a few or many)

• Compound – Pure substance that can be broken into simpler, stable substances• must have 2 different kinds of atoms

Elements vs. Compounds

Is this an element?

• Elements & Compounds can be found in many different states of matter or phases

What’s the Difference between States of Matter Video• Substances only move from one phase to another

by physical means.

States of Matter

States of

Matter

• Shape• volume

What physical characteristics can you observe to determine a substances state of matter?

Definite volumeDefinite shape Definite volume

Indefinite shape

Indefinite volumeIndefinite shape

• Plasma: high-temperature state of matter in which atoms lose most of their electrons

• Physical property – characteristic of a substance that can be observed/measured without altering substances identify

• Physical change – change in which identify of substance is not altered

Physical vs. Chemical Properties

• Physical changes will always require the absorption/release of energy• (Heat or light)

Chemical Property – ability to undergo changes that transforms substance into a new substance

Chemical change – change in which 1 or more substances are converted into different substances

What if a substance’s identity is altered?

Chemical ChangesReactants

substances that reactProducts

substances that are formedyields

Evidences of Chemical Change

Formation of a gas

Formation of precipitate

Evolution of energy (heat/light)

Color change

• Energy is always involved in physical and in chemical changes

• Law of Conservation of Energy: energy can be absorbed or released, but is never destroyed or created.

Physical Chemical Extensive

Intensive

1. Color2. Combustibility3. Hardness4. Luster5. Flammability6. Reacts with acids to form H27. Mass8. Density9. Melting Pt.10. Can neutralize a base11. Ductility 12. Odor13. Weight14. Malleability15. Tendency to corrode16. Length

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_______ 8. Wood rotting._______ 9. When placed in H2O, a sodium pellet catches on fire as H2 gas is liberated and sodium hydroxide forms._______ 10. Grass growing in a lawn._______ 11. A tire is inflated with air._______ 12. Food is digested in the stomach._______ 13. Water is absorbed by a paper towel._______ 14. Sugar dissolved in water.

_______ 1 . Hydrochloric acid reacts with potassium hydroxide to produce a salt, water and heat._______ 2. A pellet of sodium is sliced in two._______ 3. Water is heated and changed to steam._______ 4. Iron rusts._______ 5. Evaporation_______ 6. Milk sours._______ 7. Ice melting.

C

P

P

P

P

P

P

P C

C

C

CC

C

GROUPING MATTER TO MAKE IDENTIFICATION EASIERClassification of Matter

Blend of 2 or more kinds of matter, each that retain its own identify and properties• Mixed together physically• Can be separated physically (no chemical rxn’s

needed)

• Homogeneous (solutions): uniform in composition•Salt – water solution

• Heterogeneous: not uniform throughout•Clay-water mixture

Mixtures

HOMOGENOUS MIXTURE

HETEROGENEOUS MIXTURE

• Suspensions – particles in solvent so large that they settle out unless constantly stirred/agitated• Colloids – particles of

intermediate size that stay dispersed throughout a mixture.• Often appears cloudy• Use Tyndall Effect to identify

(shine light source through mixture and particles become visible in beam of light)

Heterogeneous Mixtures

Fixed composition• Every sample of pure substance has exactly the

same properties and composition

• Ex: Water is always 11.2% hydrogen and 88.8% oxygen by mass (determined from periodic table)

Pure Substances

Column APure substance or

mixture

Column BElement or

Compound/Heterogeneous or

Homogeneous1. Chlorine2. Water3. Soil4. Sugar water5. Oxygen6. Carbon dioxide7. Rocky road ice cream8. Alcohol (in water)9. Pure air10. Iron

PurePure

Mixture

Pure

MixturePure

Mixture

MixtureMixture

Pure Element

CompoundElement

Compound

Element

HomogeneousHeterogeneous

HomogeneousHeterogeneous

Homogeneous

SECTION 1.3

Introduction to the Periodic Table

• Why don’t elements and their symbols always look like they correspond to each other?

What is the periodic table?

Periods

Groups

• The vertical columns of the periodic table are called groups, or families. • Each group contains elements with similar

chemical properties.

• The horizontal rows of elements in the periodic table are called periods. • Physical and chemical properties change

somewhat regularly across a period.

Groups & Families

4 Basic Categories of Elements

elements to the left of the zigzag line Properties of metals

• Most solids at room temperature• Malleable (hammered or rolled into thin

sheets)• Ductile (drawn into a thin wire)• conduct electricity and heat well

Metals

Gold, copper, aluminum

Metals

right of the zigzag linean element that is a poor conductor of heat and

electricity

Properties of nonmetals• many are gases• solids are brittle• poor conductors of heat and electricity

Nonmetals

(a) carbon, (b) sulfur, (c) phosphorus (d) iodine

Nonmetals

surrounds zigzag linean element that has some characteristics of metals

and some characteristics of nonmetals

Properties of metalloids• all metalloids are solids at room temperature• semiconductors of electricity• **Aluminum is not a metalloid – it’s a metal!

Metalloids

Elements in Group 18

Properties of Noble Gases• Generally unreactive (i.e. “inert”)

• Gases at room temperature• Glow if electricity is passed through them

Noble Gases