Topics to be Covered Physical & Chemical Properties Intrinsic v. Extrinsic Properties Physical...

Topics to be Covered•Physical & Chemical Properties•Intrinsic v. Extrinsic Properties•Physical and Chemical Changes

•Pure Substances•Mixtures

•States of Matter

Everything that has mass and takes up space (“volume”) is

called matter.

• Physical v. Chemical

• Intrinsic v. Extrinsic

1. Physical properties• How the item looks, smells,

behaves when it is not changing its identity.

• (Examples on next slide)

2. Chemical properties• Can only be observed when a chemical

change occurs.• Explain how reactive it is.• What it reacts with.

Intrinsic v. Extrinsic Properties

Intrinsic• Also called “intensive”

• Ex: density, conductivity, reactivity

• Do not change with the amount of material being measured.

• also called extensive

• Ex: volume and mass

• change with the amount of material being measured

Extrinsic

•submicroscopic (too small to see)

OR

•macroscopic (big enough to see)

•physical OR

•chemical

• What we observe macroscopically (smell, bubbles forming, color changes, combustion)

• indicates what is happening microscopically (breaking and forming of bonds between atoms)

Use of Models• Sometimes we use MODELS to help us

understand what is happening at the submicroscopic level

• These models are powerful tools to help scientists predict the results of experiments.

• Ex: solar system

1. Substance changes in form or appearance but does not change its chemical composition. o Ex1: all phase changes (ex: ice melting)o Ex2:cutting a piece of wood into small pieces

2. Properties of that substance do not changeoEx: melting point oEx: boiling point oEx: chemical composition

3.Can be reversible* or irreversible

1. A substance changes into something new.

2. Occurs due to a chemical reaction.

3. Properties of the original substance change. Ex:the density, melting point or freezing point of original substance changes.

4. Common signs of a chemical change are often observed (Ex: bubbles form, mass changes, heat releases, etc).

5. Usually irreversible.

Classifying Matter by Composition (what it’s made of)

•Substance

•MixtureALL MATTER IS EITHER A

OR

Don’t Copy: Leave a page in your notes for this flow chart. We will complete it in class.

1. Can’t be further broken down by physical means.

2. Is pure matter

3. Has its own characteristic properties that are different from those of any other substance.

4. Has fixed composition-every sample is the same throughout

(Don’t copy: will go on flow chart.)

Compounds• Made of 2+ elements

combined chemically.• Can be decomposed into

simpler substances by chemical changes.

• Elements always in a definite ratio

• Ex: H2O, NaCl

Elements• Cannot be decomposed

into simpler substances by chemical changes

• Ex: H, He, Li, Va

(Don’t copy: will go on flow chart.)

1. 2 or more substances that are put together but NOT chemically combined.

2. Components retain their characteristic properties

3. May be separated into pure substances by physical methods

4. Composition varies from sample to sample.

(Don’t copy: will go on flow chart.)

Homogeneous-

• same composition throughout

•ex: Kool-Aid

Heterogeneous-•different composition throughout

•large pieces-easily separated by physical means (ex: density, filtration)

•ex: salad dressing

(Don’t copy: will go on flow chart.)

•Solutions are homogeneous mixtures in which there is a solvent& a solute.

•Examples: sugar water, 40% isopropyl (rubbing) alcohol, brass

•Solvent: substance that dissolves another substance. Ex: water

•Solute: substance that is being dissolved. Ex: sugar

Solutions in which the solvent is water!

Why do you think they are important?

•homogenous mixtures in which 2 or more metals have been combined.

•Examples: steel, 10 carat gold

Separating Mixtures

Filtration• Process that separates a solid

from a liquid• Uses a filter that has holes

that allow liquid to escape, but solid particles are too large

Decanting• Pouring a liquid off the top

of a solid or another liquid.

Distillation• separates a sol’n in which

the solvent has a low BP & the solute has a high BP.

• Boil away the solvent, then collect in a separate container. see picture on p 47 (CHemIH) or

Distillation Apparatus(Don’t copy, but

leave room in notes. I will have you copy a diagram.)

•Matter cannot be created nor destroyed.

•It is just converted from one form to another.

•STATES OF MATTER ARE: •Solid

•Liquid•Gas

•Plasma•Others

KMT: Particles of matter are in constant motion

Have definite shape•Particles are in fixed positions

Have definite volume•Particles touch so they can’t be compressed

Particles move: they vibrate & rotate

Have no definite shapeParticles “flow” past one another.Move more rapidly & freely than in solids.

Have definite volumeParticles touch so they can’t be compressed

Particles have “flow” (move around one another freely)

•Have no definite shape•Particles “flow” past one another.

•Have an indefinite volume•Particles are far apart from one another•Particles move much more quickly than in liquids.

•Ionized gas-made of ions and their freed electrons•Produced at very high temperatures

•Most common state of matter in the universe-about 99% of known matter.

•Least common on Earth

•Found in plasma TVs, fluorescent lights

PRODUCTS IN WHICH PLASMAS ARE USED:

(Copy a few of interest to you.)

•Computer chips &integrated circuits

•Computer hard drives

•Electronics

•Machine tools

•Medical implants&prosthetics

•Audio and video tapes

•Aircraft & auto engine parts

•Printing on plastic food containers

•Energy-efficient window coatings

•High-efficiency window coatings

•Safe drinking water

•Voice and data communications components

•Anti-scratch and anti-glare coatings on eyeglasses and other optics

Plasma-Based Water Treatment for Water Sterilization (DO NOT COPY)•intense UV emission disables the DNA of micro-organisms in the water which then can’t replicate.

•no effect on taste or smell of the water and the technique only takes about 12 seconds.

•effective against all water-born bacteria and viruses.

•especially relevant to the needs of developing countries b/c they can be made simple to use and have low maintenance and low cost.

•use about 20,000 times less energy than boiling water!

Plasma-Based UV Water Treatment Sytems, cont. (DO NOT COPY)

FYI: The slides that follow are for your

interest

(Don’t need to copy any more from this slide show.)

•Sir William Crookes, an English physicist, identified a fourth state of matter, now called plasma, in 1879

•The word "PLASMA" was first applied to ionized gas by Dr. Irving Langmuir, an American chemist and physicist, in 1929.

(Above)

X-ray view of Sun from Yohkoh, ISAS and NASA

Star formation in the Eagle Nebula

Space Telescope Science Institute

, NASA

(below)

Plasma radiation within the Princeton Tokamak during operation.

Laser plasma interaction during inertial confinement fusion test at the University of Rochester.

PLASMA•a collection of free-moving electrons and ions - atoms that have lost electrons.

•Energy is needed to strip electrons from atoms to make plasma.

•The energy can be of various origins: thermal, electrical, or light (ultraviolet light or intense visible light from a laser).

•With insufficient sustaining power, plasmas recombine into neutral gas.

Plasma can be accelerated and steered by electric and magnetic fields which allows it to be controlled and applied. Plasma research is yielding a greater understanding of the universe. It also provides many practical uses: new manufacturing techniques, consumer products, and the prospect of abundant energy.

Products manufacturedusing plasmas impact our daily lives:

•Waste processing

•Coatings and films

•Electronics

•Computer chips and integrated circuits

•Advanced materials (e.g., ceramics)

•High-efficiency lighting

Plasma technologies are important in industries with annual world markets approaching $200 billion

Drastically Reduce Landfill Size

Environmental impact:

High-temperature plasmas in arc furnaces can convert, in principle, any combination of materials to a vitrified or glassy substance with separation of molten metal. Substantial recycling is made possible with such furnaces and the highly stable, nonleachable, vitrified material can be used in landfills with essentially no environmental impact.

Electron-beam generated plasma reactors can clean up hazardous chemical waste or enable soil remediation. Such systems are highly efficient and reasonably portable, can treat very low concentrations of toxic substances, and can treat a wide range of substances.

Environmental impact: