grade 8 unit 3 structure and properties of matter 1

Grade 8 Unit 3

Structure and Properties of Matter

1

Matter is…

Write the definition of matter in your own words in your notebook

Think -Write - Pair - Share (Record in your notebook):

Is Air Matter?

Provide evidence and examples to support your answer

2

Brainstorm 20 examples of Matter

3

Chew

Partners- 5 minutes

• List 8 examples of matter and classify into the three states of matter. Make sure you have at least 2 examples in each category. Add examples if necessary.

• Explain how a substance can exist as a solid, liquid and a gas. Use a substance other than water.

4

Matter has Properties

What is a property?Add the term property to

your notebook

Physical and chemical properties

are used to identify, describe and classify matter.

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Physical Properties of Matter

Physical Properties:

♦ describe characteristics you can detect with your senses

♦ can be measured or observed without changing the makeup of the substance

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Physical Properties of Matter

Work in groups of 4-5. Select a substance in the classroom.

Describe it’s physical properties in a Bubble Map

Record in your Notebook

Groups will take turning reading the physical

properties of their object.

“The physical properties of my object are ….”

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Physical Property: Density

Density is the mass per unit volume of an object

The formula to calculate density is

Mass/Volume

Look at the formula, then answer this question:

What tools can be used to calculate density?

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Matter can exist in three states or phases:Gases, liquids and solids are all made up of microscopic particles, but the behaviors of these particles differ in the three phases.

Microscopic view of a gas.

Microscopic view of a liquid.

Microscopic view of a solid.

Particles in a Gas Particles in a Liquid Particles in a Solid

•gas are well separated with no regular arrangement.

•gas vibrate and move freely at high speeds.

•liquid are close together with no regular arrangement.

•liquid vibrate, move about, and slide past each other.

•solid are tightly packed, usually in a regular pattern.

•solid vibrate (jiggle) but generally do not move from place to place.

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Chemical Properties of Matter

• Instructional Focus: Chemical properties are characteristics observed when a substance interacts with another substance

Add the term “Chemical Properties” to your notebook

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Add examples of Chemical Properties in your notebook.

Ability to RustAbility to Digest

Flammable – The ability to catch on fire Ability to Explode

Receipts fade with light

Sensitivity to Light

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Chemical or Physical Property?

Density sensitivity to light

acidity

Atomic weight mass

flammability

Oxidation melting point toxicity

Hardness

Make a T chart and classify each of these words

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Matter is made of particles called atoms

They are everywhere and they make up everything, Look around you It is all atoms. Not just the solid things like walls and tables and sofas, but the air in between and they are there in numbers that you really cannot conceive.

Atoms are very tiny. Half a million (500,000) of them lined up shoulder to shoulder can hide behind a human hair.

Bill BrysonThe Short History of Nearly Everything

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The Atoms Family Song

1st Verse:They’re tiny and they’re teeny,Much smaller than a beany,They never can be seeny,The Atoms Family.Chorus

3rd Verse:Neutrons can be found,Where protons hang around;Electrons they surroundThe Atoms Family.Chorus

2nd Verse:Together they make gases,And liquids like molasses,And all the solid masses,The Atoms FamilyChorus

4th Verse:They are so small.(Snap, snap)They’re round like a ball.(Snap, snap)They make up the air.They’re everywhere.Can’t see them at all.(Snap, snap)

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The Structure of the Atom

Add the terms atom, proton, neutron, electron

to your notebook

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Elements Substances made of a single kind of atom

Magnesium Iron

Carbon Sulfur

Draw a graphic

representation

of 4 common

elements demonstrating

that each element is made of

one type of atom.

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Which of these represent an element?

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Metals, Nonmetals, and Metalloids

Some periodic tables are color coded to show what elements are metals, nonmetals, and metalloids.

In general, elements located in the left two-thirds or so of the periodic table are metals. The nonmetals are on the right side of the table.

The dividing line between the metals and nonmetals are elements called metalloids.

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The gray area represents the metals.

The yellow area represents the metalloids.

The blue area represents the nonmetals.

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Metals :What can you do to remember that the metals

are on the left hand side of the zig-zag line?

Periodic Table Trends:

Metals

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Non-metals :What can you do to remember that non-metals are on the right side of the zig-zag line?

Periodic Table Trends:

Non-Metals

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Trends on the Periodic Table:

Metalloids

Metalloids: What can you do to remember the

location of metalloids on the periodic table?

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Using the Box

• Each box represents a different element.

• Each box contains information that tells . .– The elements name– The elements symbol– The atomic number of the element– The atomic weight of the number

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Example

• Name – Oxygen

• Atomic Number – 8

• Atomic Symbol – O

• Atomic Weight – 16.00

Oxygen

8

16.00

O

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Organization of the The Periodic Table of Elements

Atomic Number The number of protons in an atom “The number of protons is what gives an atom its chemical

identify. An atom with 1 proton is an atom of hydrogen, an atom with 2 protons is an atom of helium, etc.

The number of electrons in an atom Electrons give an atom its “personality”

Atomic Mass The number of protons and neutrons in an atom

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The Relationship between Atomic Number

and Atomic Mass

• The number of neutrons in an atom equals the atomic mass minus the atomic number.

• Quick Check: How many neutrons are in an atom of Chlorine? Use the periodic table on your formula chart.

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The Relationship between Atomic Number and Atomic Mass

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Making Connections Creating an Atomic Model

• # of protons = atomic number• # of electrons = protons in an atom• # of neutrons = atomic mass minus

the atomic number • Example: Carbon • 6 + 6 = atomic mass = 12 • - 6

6

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The Periodic Table Is . .• A table of all known elements,• A useful tool for scientists,• And, it arranges elements according to

their properties.

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What happens to the atomic number as you move across the table?

What happens to the atomic mass as you move down the table?

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Reading a Periodic Table

• When reading a periodic table . . . .– Look at the box– Look at the columns (group or family)– Look at the rows (periods)– Look at the location of metals, nonmetals, and

metalloids

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Using the Columns

• Each column of elements is called a family or group.

• Elements in a family have similar but not identical properties.

• The number for the column indicates the number of electrons in outer shells of the element.

• Elements in a group have the same number of electrons in their outer orbital.

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Groups/Families and Periods

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Families or Groups•Elements in the red group

have 1 electron in their outer shell.

•Elements in the orange group have 2 electrons in

their outer shell.•As you keep counting the

colored columns, you add an additional electron.

•Purple has 8 electrons in its outer shell.

•(Don’t include the white group)

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Using the Rows

• Rows represent an element’s period.

• Elements in a period are not alike in properties.

• Even though some squares are skipped in between, all of the rows go from left to right.

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Periods

•Every element in the top row (first period) has one orbital for its electrons.•Every element in the

second row (the second period) have two orbitals

available.

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The Inventor

• Created by Dmitri Mendeleev.• Mendeleev was a teacher who

was discouraged by his teaching tools and decided to create his own.

• He made note cards of the elements known at that time and arranged them. When there wasn’t an element to fit a certain spot, he left it open and predicted an element would be found later to fill it.

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Valence ElectronsValence electrons are the electrons in the

last energy level of an atom.

Valence electrons are important in determining how an element reacts chemically with other elements: The

fewer valence electrons an atom holds, the less stable it becomes and the more

likely it is to react.

38

Predict the number of Valence Electrons in the following:

• K• AL• AS• F

Write these down, then share your answers

39

40

Review

Physical Properties

Physical Changes

Chemical Changes

LecturePLUS Equation PPT Karen Timberlake

Physical Properties

color

melting point

boiling point

electrical conductivity

specific heat

density

state (solid, liquid, or gas)

3

LecturePLUS Equation PPT Karen Timberlake

Physical Change

Changes in physical properties melting boilingcondensation

No change occurs in the identity of the substance

Example:

Ice , rain, and steam are all water4

LecturePLUS Equation PPT Karen Timberlake

43

What terms are used to describe physical changes?

• Cutting • Sawing• Sanding • Breaking • Denting • Squeezing • Stretching • Snapping • Soiling • Dying • Heating • Drying

• Cooling • Expanding • Contracting • Melting • Freezing • Boiling • Evaporating • Condensing • Mixing • Dissolving • Soaking

Add the term “Physical

Changes” to your notebook

LecturePLUS Equation PPT Karen Timberlake

Chemical Change

Atoms in the reactants are rearranged to form one or more different substances

Old bonds are broken; new bonds form

Examples:

Fe and O2 form rust (Fe2O3)

Ag and S form tarnish (Ag2S)

6

What terms are used to describe chemical changes?

Evidence of Chemical Change

• Production of a gas • Change of temperature • Formation of a new

substance • Production of a solid• Production of light • Change of color

Examples of Chemical Change

• Rusting• Burning• Souring• Rotting• Tarnishing• Digesting

Add the term Chemical Changes to your notebook

7

LecturePLUS Equation PPT Karen Timberlake

46

Evidence of a Chemical Change

• production of a gas

• change of temperature

• formation of a new substance

• production of light

• change of color.

LecturePLUS Equation PPT Karen Timberlake

47

Production of Gas

• Photosynthesis, stomach digesting food! Both of these produce gas.

Photosynthesis Gas Production

Test Tube with

Gas

LecturePLUS Equation PPT Karen Timberlake

48

Change in Temperature

• Natural Gas burning to heat your home

• A hot/cold pack when crushed to activate.

Combustion

Combustion means burning. It is a type of chemical change.

52

LecturePLUS Equation PPT Karen Timberlake

50

Change in Properties

• A chemical change has occurred when a totally new substance with new properties has been formed.

PLUS EQUALS

TarnishingTo dull the luster of a metal, especially by

oxidation

Ring after tarnish is chemically removed

Some metals tarnish

with a green color

54

Souringprocess of spoiling

This milk has started to sour- notice the solid clumps in the

bottom of the jar

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LecturePLUS Equation PPT Karen Timberlake

53

Precipitate Forms

• This is when you mix two things and one of them react forming a new substance, usually a new color:

Example:

LecturePLUS Equation PPT Karen Timberlake

54

Production of Light

LecturePLUS Equation PPT Karen Timberlake

55

Change in Color:

Examples:– Leaves changing on the trees….– Rust forming on an old swing set….

RustingWhen iron chemically combines with oxygen

What is the evidence of Chemical Change?59

Rottingto decompose or decay

mold60

Mini Lab: Chemical Change

Students will:

• Record the properties of the reactants (steel wool and oxygen (O2)

• Record the properties of the product.

• What evidence indicates that a chemical change has taken place?

• What evidence indicates that a new product was formed?

61

LecturePLUS Equation PPT Karen Timberlake

59

http://www.sasksch

ools.ca/curr_content/

science9/chemistry/

lesson8.html

Review each

picture and

identify the evidence

of a chemical

change.

LecturePLUS Equation PPT Karen Timberlake

60

What terms are used to describe chemical changes?

• Production of a gas • Change of

temperature • Formation of a new

substance Production of a solid

• production of light • Change of color

• Rusting• Burning• Souring• Rotting• Tarnishing• Digesting

Add the term “Chemical Change” to your notebook

LecturePLUS Equation PPT Karen Timberlake

61

LecturePLUS Equation PPT Karen Timberlake

Learning Check E1

Classify each of the following as a

1) physical change or 2) chemical change

A. ____ a burning candle

B. ____ melting ice

C. ____ toasting a marshmallow

D. ____ cutting a pizza

E. ____ polishing silver

65

LecturePLUS Equation PPT Karen Timberlake

Solution E1

Classify each of the following as a

1) physical change or 2) chemical change

A. __2__ a burning candle

B. __1_ melting ice

C. __2__ toasting a marshmallow

D. __1__ cutting a pizza

E. __2__ polishing silver 66

Coefficients, the numbers placed in front of formulas to balance equations. They indicate the number of particles present in the reaction. If a number is not present it is understood that 1 is the coefficient.

2 H2 + O2 2 H2O

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2H2O

Coefficient

subscript

Coefficients are used to balance equations. NEVER change or add subscripts!

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2H2O

Coefficient

subscript

Coefficients are used to balance equations. NEVER change or add subscripts!

69

How molecules are symbolizedCl2 2Cl 2Cl2

• Molecules may also have brackets to indicate numbers of atoms. E.g. Ca(OH)2

O H

O H

Ca• Notice that the OH is a group• The 2 refers to both H and O

• How many of each atom are in the following?a) NaOH

b) Ca(OH)2c) 3Ca(OH)2Na = 1, O = 1, H = 1

Ca = 1, O = 2, H = 2Ca = 3, O = 6, H = 6

Subscripts vs. Subscripts vs. CoefficientsCoefficients

• The subscripts The subscripts tell you how tell you how many atoms of many atoms of a particular a particular element are in a element are in a compound. The compound. The coefficient tells coefficient tells you about the you about the quantity, or quantity, or number, of number, of molecules of molecules of the compound.the compound.

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Use the Coefficients and Subscripts to determine the number of atoms and molecules in each equation

1. 2H2 + O2 ---> 2H2O

2. S8 + 12O2 ---> 8SO3

3. HgO ---> Hg + O2

4. Zn + HCl ---> ZnCl2 + H2

5. 2Na + 2H2O ---> 2NaOH + H2

6. 2Al + 3FeO ---> Al2O3 + 3Fe

7. Fe + O2 ---> Fe2O3

Chemical Reactions

• a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds.

• A chemical reaction rearranges the atoms of the reactants to create different substances as products.

Chemical ReactionsChunk:

• Reactant: Starting materials in a chemical reaction

• Product: A substance formed as a result of a chemical reaction

• Chemical reactions are characterized by a chemical change, and they yield one or more products which are, in general, different from the reactants (the original chemicals).

A + B AB

Reactants Products

CHEMICAL REACTIONSCHEMICAL REACTIONS

Reactants: Zn + IReactants: Zn + I22 Product: Zn IProduct: Zn I22

The Purpose of Chemical Equations

Recognize the importance of formulas and equations to express what happens in a chemical reaction

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Learning the difference between coefficients and subscripts

Move your mouse over the graphic to animate

• The charcoal used in a grill is basically carbon. The carbon reacts with oxygen to yield carbon dioxide. The chemical equation for this reaction, C + O2 CO2, contains the same information as the English sentence but has quantitative meaning as well.

C + O2 CO2

This reads “carbon plus oxygen react to yield carbon dioxide

Fe and O2 form rust (Fe2O3)This reads iron plus oxygen react to yield iron oxide (rust)

Reading Chemical Reading Chemical EquationsEquations

Writing a Chemical Equation“Chew”

12 oz of dough, 4 oz mushrooms, 12 slices pepperoni, 8 oz cheese and 5 oz tomato sauce are used to

make a pizza. Write a recipe in words for putting together a pizza.

1. Identify the reactants

2. Identify the products

3. Write the recipe as a chemical equations

Chew Format:

1st – Individual

2nd- Pair/Share and reach consensus on the correct answer

LecturePLUS Equation PPT Karen Timberlake

78

Checking for Understanding

12 oz of dough, 4 oz mushrooms, 12 slices pepperoni, 8 oz cheese and 5 oz tomato sauce are used to make a pizza. Write a recipe in words for putting together a pizza.

12 oz of dough + 4 oz. mushrooms + 12 slices of pepperoni + 8 oz. of cheese + 5 oz of tomato sauce 1 pizza

The Law of conservation of mass states that matter cannot be created or destroyed in

any chemical reaction

The atoms in the reactants are rearranged to form new compounds, but none of the atoms disappear, and no new atoms are

formed.

Conservation of Mass

H H

H2

H H

H2

O O

O2

+ +The atoms

are rearranged

OH H

H2O

Same numbers and kinds of atoms

on each side of the arrow

OH H

H2O

4 Hydrogen 4 Hydrogen

2 Oxygen 2 Oxygen

LecturePLUS Equation PPT Karen Timberlake

81

Lab: Mass Stays Constant

Observe that mass remains constant before, during, and following chemical reactions.

• Place balloon,small beaker with 15mL of water, and half effervescent tablet on balance and measure mass.

• Then place water and tablet in balloon, seal balloon, allow water and tablet to react while on balance, and continue to monitor mass.

• Report observations and explanations. Base explanations on evidence, logic, and scientific knowledge.

Does the Equation represent Conservation of Mass?

• Zn + HCl ---> ZnCl2 + H2

• 2Al + 3FeO ---> Al2O3 + 3F

• KClO3 ---> KClO4 + KCl

• 2C2H2 + 5O2 ---> 4CO2 + 2H2O

• SiO2 + 4HF ---> SiF4 + 2H2O