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�How can matter classified?

�Why are carbon and copper classified as elements?

�How are elements related to compounds?

�What is the difference between a pure substance and a mixture?

Atoms Video

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�What is matter?

�How can matter be classified?

�Chemistry- study of matter and how it changes�Helps you recognize how differences in material properties relate to what the materials are made of

WHAT IS MATTER

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WHAT IS MATTER

�Matter - Anything which has mass and takes up space.�If you can touch it, it is certainly matter

�Ex: air, animals, rocks, plants, water, etc

�Two types of matter-�Substance- Pure

�Mixture- more than one substanceWhat are two examples not classified

as matter? Light and Sound

�Sound

�Air

�Electricity

�Fire

�Computers

�X-Rays

�Books

�Pencils

�Light

�Magnetism

�Water

�Wood

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The fundamental building blocks of

matter are atoms and molecules.

ATOM MOLECULESmallest unit of

an element that

retains the

properties of that

element.

When two or

atoms bond

together by

covalent bonds.

More than 100 different types of atoms. Combine in different ways to make up anything that you can think of.

WHAT IS MATTER?

� There are two kinds of substances:� Elements

� Compounds

TWO TYPES OF SUBSTANCES

Carbon atoms

Gold atomsCopper atoms

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A pure substance made of only one kind of atom.

ELEMENTS

Elements are found on the Periodic Table of Elements

116 elements have been identified

• 83 elements occur naturally on Earth: gold, aluminum, lead, oxygen, carbon

• 33 elements have been created by

scientist: technecium, amerecium, seaborgium

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2. COMPOUNDS

�Compound- substance made of atoms of more than one element bound together�Atoms stick together to make molecules

�All molecules of a compound are the same

�Compounds behave completely differently from the elements that make them

TWO TYPES OF SUBSTANCES

Why is water a compound?

Two DIFFERENT types of atoms.

Compounds can only be separated by

chemical means into their pure components

(elements).

Water (H2O)

Sucrose (C12H22O11)

Ammonia (NH3)

Animation

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� Chemical symbols & # indicating atoms contained in basic unit of substance

� # of atoms of each element in basic unit written after element’s symbol as subscript

� No subscript is used if only 1 atom of an element is present

� # placed in front of formula show # of molecules

COMPOUNDS

H2O

2 Hydrogen atoms1 Oxygen atom

C12H22O11

12 Carbon atoms

22 Hydrogen atoms

11 Oxygen atoms

�3C16H10N2O2 (Indigo)

�5CO2

�SO2

�2HCl

�6C12H22O11 (Table sugar)

�4C6H12O6 (Glucose)

�12O2

�7NH3 (Ammonia)

�O3 (Ozone)

�55H2O

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PURE SUBSTANCES

�A sample of matter that has definite chemical and physical properties.• Every part of a given substance has the same properties

because a pure substance is a fixed, uniform composition.

• Examples: table salt and sugar

�Elements and compounds are pure substances, but mixtures are not.

TWO TYPES OF SUBSTANCES

�Carbon

�Proton

�Aluminum

�Water

�Neutron

�Sugar

�Electron

�Salt

�Iron

�Glass

�Copper

Element

Element

Element

Element

Compound

Compound

Compound

Compound

Atom

Atom

Atom

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MIXTURES

�Matter that consists of two or more substances mixed together.

�NOT chemically combined�Substances in mixture KEEP their chemical and physical properties

�Can be in any proportion

� Examples: Grape juice, air, fruit salad

•The substances are not bonded together. •Nothing new is created. It is the just the same substances mixed together.

Heterogeneous

�Different from place to place

� Parts are noticeably different

�Not evenly mixed� Ex. Sand, gravel, mixed nuts

� The same throughout�Difficult to distinguish one substance from another

� Evenly mixed�Also called solution� Ex. Kool-aid, sea water, air

MIXTURES

Homogeneous

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Separated by

chemical methods

Homogeneous mixture or Heterogeneous mixture

Heterogeneous Homogeneous

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Homogeneous mixture or Heterogeneous mixture

HeterogeneousHomogeneous

88% copper and 12% tin

Miscible-�Liquids that do dissolve in each other

�Homogeneous

�Gasoline

�Liquids that don’t dissolve in each other

�Heterogeneous

�Oil and water

LIQUID MIXTURES

Immiscible-

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SECTION 2: PROPERTIES

OF MATTER

�Why are color, volume and density classified as physical properties?

�Why are flammability and reactivity classified as chemical properties?

� In any physical or chemical change, matter is neither created nor destroyed

� Matter can be changed from one form to another.

Copyright © 2010 Ryan P. Murphy

What is the Law of Conservation of Matter?

Describe what happens to the wood when we

burn it?

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�Allow us to identify substances

�Allow us to separate substances

�Determine uses

�Two type of properties:

�1. Physical

�2. Chemical

PROPERTIES

PHYSICAL PROPERTIES

�A physical property can be observed or measured without changing the composition of the substance.

•Help identify substances.

•Can be observed or measured. • (Example: Melting Point and Boiling Point)

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Examples:• Shape, color, odor,

texture,

• Melting point (S to L),

boiling point (L to G),

• Strength, hardness,

conductivity,

magnetism, heat

• Density

PHYSICAL PROPERTIES

Durable: able to withstand damage or wear.Flexible: capable of bending easily without breaking

Physical Properties determine uses!

What would happen if you poured a hot drink into a metal cup?

PHYSICAL PROPERTIES

�Examples:

� Aluminum is used in foil because it is light weight and yet durable and flexible.

� Steel is used in cars because it is strong and provides structure.

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DENSITY

•Density is the mass per unit volume of a substance.

•Tells us how light or heavy something is.

PHYSICAL PROPERTIES

Which is denser?

Why?

Sentence:

�A lead brick is heavier than a sponge of the same size because lead is denser than sponge.

� Seawater is denser than freshwater because it contains more dissolved salts ☺☺☺☺

Density

Write a sentence comparing two objects similar

to the sentences above.

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Why the difference in volume even though their weight is the same?

Tightness of the composition of

substances in object

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� Divide the mass of the object by the volume of the object

Density = Mass

Volume

SI units

�Density = g/mL or g/cm3

�Mass = g

�Volume = mL or cm3

�Water has a density of 1 g/mL

M

D V

1. A small block of wood has a volume of 25 cm3

and a mass of 20 grams. What is the density of the block?

Density = mass

volume

D =?

M = 20 grams

V = 25 cm3

Density = 20g

25cm3

Density = 0.8 g/cm3

2. A piece of tin has a mass of 16.52 g and a volume of 2.26 cm3? What is the density of tin?

D =?

M = 16.52 grams

V = 2.26 cm3

Density = mass

volume

Density = 16.52 g

2.26 cm3

Density = 7.31 g/cm3

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3. A man has bottle completely filled with 163 g of a slimy, green liquid and a density of 3.26 g/cm3. What is the volume of the bottle?

4. A piece of metal has a density of 11.3 g/cm3

and a volume of 6.7 cm3. What is the mass of this piece of metal?

D= 3.26 g/cm3

M= 163 g

V= ?

Volume = Mass

Density

Volume =163 g

3.26 g/cm3

Volume=50.0 cm3

D= 11.3 g/cm3

M= ?

V= 6.7 cm3

Mass = Density x Volume Mass= 11.3 g/cm3 x 6.7 cm3

Mass= 76 g

Wood Water Iron

1 cm3 1 cm3 1 cm3

If you take the same volume of different

substances, then they will weigh different amounts.

0.50 g 1.00 g

8.00 g

Q) Which has the greatest mass and therefore the most dense?

IRON

DENSITY IS DIFFERENT FROM

WEIGHT

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� 1.0 g/mL

�By comparing densities!

� Density is useful because it can be used to identify a substance.

� For example, aluminum always has a density of 2.55 g/ml.

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�Way substance reacts with others to form new substances with different properties

� How it changes:

� By combining with other substances

� Or breaking apart

� Examples:� Sodium reacts easily with other elements.

� Gold does not like to react and is usually found alone.

� Argon does not react and is the gas that is in light bulbs.

� Iron will rust, carbon is flammable.

CHEMICAL PROPERTIES

Na + Cl =>

�Reactivity is the capacity of a substance to combine with another substance.

�Flammability, rust

�Flammability is the ability to burn.� If you burn anything, you change the chemical composition of that substance

and you cannot turn it back into what you started with.

CHEMICAL PROPERTIES

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P r o p e r t i e s o f M a t t e r

Physical Chemical

Can be observed or measured

without changing the identity of the

substance.

Examples of Property

Substance interacts with other

substances to produce new

substances.

Reactivity

Flammability

Rust

Cooking

Burning

color

odor

taste

hardness

density

melting points

freezing points

Examples of Property

Comparison of Physical and Chemical Properties

Substance Wood Iron Red dye

Physical

Property

Chemical

Property

Has a

grainy

texture

Bends

without

breaking

Has red

color

Is flammableReacts with

oxygen to

form rust

Reacts

with

bleach,

loses color

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�Why is getting a haircut an example of a physical change?

�Why is baking bread an example of a chemical change?

�How can mixture and compounds be broken down?

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Changes of Matter

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1. Physical Change: occurs without a change in composition, but when the physical form or properties are changed.�The atoms are not changed or rearranged.

Physical Changes

Examples:• Grinding peanuts into

peanut butter.• Pounding a gold

nugget into a ring.• Dissolving, cutting,

crushing, etc.• Melting ice cubes or

gold.• Any phase changes

(solid, liquid, gas)

Physical Changes

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Write some examples.

1. A change in physical properties, but there is no change in the substances' chemical properties or chemical composition.

2. No new substance is formed.

3. It is a change from one phase of matter to another.

4. Examples include: grinding, cutting, melting, and boiling. These types of changes do not change the identity of the substance.

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2. Chemical Change: happens when one or more substances are changed into entirely new substances that have different properties.

�The substances after the change are different from the substances at the beginning.

Chemical Changes

Chemical ChangesClues often suggest that a chemical change has

happened.

•A change in odor

•Color changes

•Fizzing or foaming

from gas being given

off

•Production of sound,

heat, light, or odor. CO2 being formed

What color was the Statue of Liberty originally? Why

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Examples:• When you burn anything.• When a battery dies, the chemicals inside have changed.• When you breathe in oxygen and air, but breathe out

carbon dioxide.• When you mix vinegar and baking soda and get a gas and

a saltwater.• Leaves changing color in the fall.

Chemical Changes

C₆H₁₂O₆ + 6O₂→ 6CO₂ + 6H₂O + energy

Ch

em

ical

Ch

an

ges

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Because new substances are formed in a

chemical change, they cannot be reversed by

physical changes!

Chemical Changes

Practice Problems

Indicate if each of the following is a physical

or a chemical change:

a) Tearing a sheet of paper

b) Burning a log

c) Melting a piece of wax

d) Melted butter solidifies in the refrigerator

e) The rusting of iron

f) The dissolving of sugar in water

Answers

a) Physical

b) Chemical

c) Physical

d) Physical

e) Chemical

f) Physical

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Mixtures

�Separated by physical changes• Physical removal of parts

(pizza toppings)• Evaporation (seawater)• Boiling or distillation • Centrifugation or spinning

rapidly (blood)

• Each of the individual substances retains its own individual properties

Compounds

�Must be broken down by chemical changes.�Heating�Using electric current

(breaking up table salt into sodium and chloride)

�Chemical reactions (breaking compounds into simpler substances, which can be broken down into elements)

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Breaking Down Mixtures &

Compounds

METHODS OF SEPARATING MIXTURES INTO THEIR INDIVIDUAL COMPONENTS:

Filtration

Evaporation

Decanting

Centrifuge Paper

Chromatography

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