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MATTER DOE S MA TTER, MA TTER ?
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Page 1: Chapter 16  chemistry grades 5-8

MATTE

R

DO

ES

MA

T TE

R,

MA

T TE

R?

Page 2: Chapter 16  chemistry grades 5-8

16-1 FUNDAMENTALS OF MATTER

Objectives:

Explain what a scientific model is

Identify individuals who contributed to the advancement of chemistry

Page 3: Chapter 16  chemistry grades 5-8

FUNDAMENTALS OF MATTER

Scientist use models, but not always physical objects:

instead they are explanations that improve scientists’ understanding of what is being studied.

Page 4: Chapter 16  chemistry grades 5-8

MATTER

Scientists have used many models in studying matter

Matter is anything that has mass and takes up space.

Aristotle, a Greek teacher who lived more than 2000 years ago, was one of the first to study matter.

Aristotle’s model of matter was that everything was made from four elements: earth, air, fire, and water.

wood was thought to be earth and fire.

steam was thought to be a combination of water and fire

Page 5: Chapter 16  chemistry grades 5-8

DEMOCRITUS

Greek Scientist

believed everything was made up of tiny unbreakable spheres.

these spheres could not be made any smaller than they already were

named these little units “atoms” because the Greek work atomos meant “cannot be divided”

believed that an atom could connect with other atoms to form al kinds of matter

Page 6: Chapter 16  chemistry grades 5-8

LATER SCIENTISTSJohn Dalton

proved that matter was made of atoms and they did connect to form different types of matter

J. J. Thompson

discovered that atoms contained small particles with a negative charge

he called them corpuscles and he believed that they floated randomly inside the atom.

today we call them electrons

Ernest Rutherford

created a new model for explaining the structure of the atom

atom not solid, but mostly empty space

only the center was solid and he called it the nucleus

Later scientists discovered positively charged particles in the center of the atom, these are called protons.

Page 7: Chapter 16  chemistry grades 5-8

DID YOU KNOW?

If all the space were taken out of the atoms that make up your body, and the electrons, protons, and neutrons were forced together, the total volume of your body would be less than that of a grain of sand!!!

An atom is so empty that if it were the size of the Earth (13000km) its nucleus would be less than 2 km across.

Page 8: Chapter 16  chemistry grades 5-8

MORE LATER SCIENTISTS

In 1913, Neils Bohr proposed that the negatively charged electrons circle the nucleus in established orbits like planets revolve around the sun.

This planetary model worked for some atoms but not for all.

James Chadwick

discovered another type of particle in the nucleus next to the protons.

these particles lacked any electrical charge and were neutrons.

Current thinking

scientists believe that the atom is best explained by the electron-cloud model

Page 9: Chapter 16  chemistry grades 5-8

ELECTRON-CLOUD MODEL

Page 10: Chapter 16  chemistry grades 5-8

16-2: STATES OF MATTER

Objectives:

compare and contrast the states of matter

describe how the kinetic-molecular theory relates to changes of matter

Page 11: Chapter 16  chemistry grades 5-8

STATES OF MATTER

Solids: keep the same shape and volume and when heated they change shapes

Liquids: always keep the same volume but change shape depending on the container they are in.

Gas: has no fixed shape or volume. It retains the shape and volume of its container.

Plasma: consists of matter that has lost electrons. It usually exists at extremely high temperatures such as those found on the sun.

Page 12: Chapter 16  chemistry grades 5-8

Click icon to add picture

SOLIDS

Mol

ecule

s of

sol

ids

have

the

leas

t kin

etic

ener

gy

Definite

shap

e

Definite

vol

ume

When

hea

ted th

ey c

hange

shap

e

Page 13: Chapter 16  chemistry grades 5-8

Click icon to add pictureLIQUID

S

Mole

cule

s of

liquid

s hav

e m

ore

kinet

ic e

nergy

than

solid

s, b

ut les

s

than

gas

es.

Indefi

nite s

hape.

Definite

volu

me

When

hea

ted, a

liquid

usu

ally

chan

ges to

a g

as

When

coo

led, a

liquid

usu

ally

chan

ges to

a s

olid

.

Page 14: Chapter 16  chemistry grades 5-8

Click icon to add pictureGASES

Mol

ecule

s of

gas

es h

ave

the

great

est k

inet

ic e

nergy

Indefi

nite s

hape

Indefi

nite v

olum

e

When

coo

led, a

gas

usu

ally

chan

ges to

a li

quid.

Page 15: Chapter 16  chemistry grades 5-8

KINETIC

Kinetic refers to the energy of motion.

Kinetic-molecular theory deals with the motion of atoms.

according to this theory, all atoms have energy: hence, all atoms move.

atoms of solids have less kinetic energy than atoms of liquids and gases, making them move more slowly.

the slower movement allows these atoms to hold tightly to surrounding atoms.

in liquid state atoms have more energy, they move faster and bounce farther off each other

in gaseous form, atoms have the highest energy and move the fastest and farthest apart.

Page 16: Chapter 16  chemistry grades 5-8

SUBLIMATION

At times, matter can change from a solid to a gas, or a gas to a solid, without becoming a liquid in a process called sublimation.

Iodine crystals are heated, the atoms gain energy and move far apart and become a gas.

Dry Ice is another example.

Page 17: Chapter 16  chemistry grades 5-8

PROPE

RTIE

S OF

MATTE

R

Page 18: Chapter 16  chemistry grades 5-8

16-3: PROPERTIES OF MATTER

P H Y S I C A L P R O P E R T I E S

Silver’s bright shiny luster

Water boils at 100°C

Chalk comes in many colors

Lipstick is made in many shades

Hard candies are sweet

Aluminum can be hammered into thin sheets to form foil

C H E M I C A L P R O P E R T I E S

Statues of marble and bronze corroded by acids

Hardness of diamonds

Drain cleaner dissolves substances

Starter fluid helps charcoal briquettes burn

Silver compound in photographic film breaks down in light to form pictures

Page 19: Chapter 16  chemistry grades 5-8

PHYSICAL PROPERTIES

Physical properties can be observed by the senses

They include:

color

shape

odor

taste

form

Other properties:

density

texture

hardness

Page 20: Chapter 16  chemistry grades 5-8

CHEMICAL PROPERTIES

Describes how different types of matter combine or interact with each other to form new substances.

Reaction with oxygen: if paper becomes warm enough, it will combine with oxygen in the air and burn

Reaction with acid: iron will react with the oxygen in water to form rust.

If baking soda combines with vinegar (an acid) bubbles of carbon dioxide gas are produced. If baking soda combines with water instead of vinegar, no bubbles are produced.

Page 21: Chapter 16  chemistry grades 5-8

16-4: CHANGES OF MATTER

Objectives:

Distinguish between physical and chemical changes.

Page 22: Chapter 16  chemistry grades 5-8

CHANGES OF MATTER

Matter has both physical and chemical properties and can go through physical and chemical changes.

Physical changes:

changes in which the properties of matter change but the identity of the matter does not.

cutting wire

grinding crystal

melting a metal

All of these physical changes make matter look different, but they don’t change what it is.

Page 23: Chapter 16  chemistry grades 5-8

CHEMICAL CHANGES

Chemical changes are those in which one type of matter is changes into another type of matter having different properties.

While absolute proof of a chemical change is provided only by chemical analysis, certain easily observed changes provide strong evidence that chemical changes have occurred.

production of heat or light

production of a gas

production of a precipitate, a solid substance that separates from solution

Page 24: Chapter 16  chemistry grades 5-8

COMPOUNDS

Creat

ed w

hen tw

o or

mor

e diff

eren

t kin

ds of

ato

ms

com

bine

Page 25: Chapter 16  chemistry grades 5-8

IRON O

XIDE

Iron re

acts

with

oxy

gen