Chemistry - 8th Grade - Elements, Mixtures and Solutions

St. George's College

Subject: 8th CHEMISTRY

Class: Elements, Mixtures and Solutions

Teacher's notes

Objectives

Vocabulary Link and Learn

Date: August 10th

Prepared by

In‐Class Survey

2009 1

8th Milton A ‐ Elements, Mixtures and Combinations Name

Oral Intervention

Sergio

María Fernanda Alejandra Almendra Anna Paula Sandra E‐C Maia María Belén Alfredo Kinley Arianne Sandra M. Fiorella Rodrigo Giulia Jaime Stefano Bruno

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8th Milton Alpha ‐ Elements, Mixtures and Combinations Name

Oral Intervention

Marcelo Antonella Paulo Alejandro Brenda Diego Gabriel Valeria Cristina Giuliana Joshua María Gracia Gonzalo N. Paolo Gonzalo R. Giorgio Nicolás María Claudia

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Let's remember previous learned concepts...

Wanna Play?

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Matter

• Two principal ways of classifying matter are according to its physical state (gas, liquid, solid) and according to its composition (as an element, compound, or mixture).

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Pure Substances • A pure substance is matter that has distinct properties and a composition that doesn't change from sample to sample.

• All substances are either elements or compounds.

• Elements cannot be decomposed into simpler substances.

• Compounds are substances composed of two or more elements.

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Mixtures of Elements and a Compound

Atoms of an Element

Molecules of a Compound

Molecules of an Element

Match the sentences to its corresponding picture 7

Elements • There are 118 known elements (natural and artificial).

• However, only five elements account for over 90% of the Earth's crust: oxygen, silicon, aluminum, iron and calcium.

• In contrast, just three elements account for over 90% of the mass of the human body: oxygen, carbon and hydrogen.

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New knowledge beginning......

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Compounds • Most elements can interact with other elements to form compounds.

• Compounds are substances composed of two or more elements.

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Mixtures

• A Mixture contains more than one substance.

• Each substance in a mixture retains its own chemical identity and properties.

• Most of the matter we encounter consists of mixtures of different substances.

• Whereas pure substances have fixed compositions, the compositions of mixtures can vary.

• Some mixtures, do not have the same composition, properties, and appearance throughout the mixture.

• Such mixtures are heterogeneous (For example: such as sand, rocks, and wood).

• Mixtures that are uniform throughout are called homogeneous.

Combinations

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Mixture

Non窶信ixture

Combination

Solution

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Properties of Matter • Every substance has a unique set of properties, or characteristics that allow us to recognize and distinguish one substance from another.

• Properties can be: physical or chemical.

• Physical properties can be measured without changing the identity and composition of the substance. For example: Color, odor, density, melting point, boiling point, hardness, etc.

• Chemical properties describe the way a substance may change or react to form other substances. For example: Flammability.

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Types of Mixtures • A Solution is a special kind of mixture, where mixing occurs at the molecular level.

• Thus, all solutions are mixtures, but not all mixtures are solutions.

• Mixtures can be made from any number of components, and these components can come from any of the three states of matter: solid (S), liquid (L), or gas (G).

• So, if we just consider binary (two‐component) mixtures, then we can have mixtures of six types: S/S, S/L, S/G, L/L, L/G, G/G. • Moreover, these combinations could (at least in principle) be either physical mixtures or solutions.

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Place the substances shown in its corresponding category.

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Liquid/Solid Mixtures Physical Mixtures • Mud: mixture of water and dirt.

Does dirt dissolve in water?

• Skim Milk: mostly water, with very small particles ("micelles") of protein (casein). Casein scatters light, therefore the white color. When milk is coagulated, casein forms cuddles.

• Latex paint: typically 70% water, 30% polymer. This polymer scatters light, so gives it a white color. Latex paint is formulated to avoid coagulation.

Solutions • Kool‐Aid: A mixture of water (liquid), sugar (solid), and flavor (crystals or powder).

Typically clear (see‐through) although colored.

• Seawater: a mixture of water (liquid) and a variety of solid minerals (sodium chloride, etc). Seawater is also clear, making it a typical solution.

Suspensions • A solid substance suspended, and not dissolved in water, but small enough not to be seen forms a Suspension.

Recommended: Find out about: emulsion, gel.

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ASSIGNMENT

NOTEBOOK 1. Complement the Class by finding out and writing in your notebook, the definitions, properties and examples of the following types of mixtures: • Liquid / Liquid Mixtures • Liquid / Gas Mixtures • Solid / Solid Mixtures 2. Deadline: • Group A: Thursday, August 13th.

• Group Alpha: Wednesday, August 12th.

3. Criteria of Evaluation: • (5 p) Compliance with the Deadline • (5 p) Quality of Information • (5 p) Organization‐Presentation • (5 p) Optional: Make a Web Diagram having MATTER as the central idea.

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Resources Used Slide (Group)

Resource

Description

Origin

G1 ‐ 2

Image

Milton

http://bit.ly/XQqEw

G1 ‐ 3

Image

Milton

http://bit.ly/XQqEw

G1 ‐ 4 Animation Idea

Notebook Gallery

G1 ‐ 5

States of Matter Solutions

http://bit.ly/NLDJ5 http://bit.ly/3XskQK

G1 ‐ 7 Images

Elements, Molecules

http://bit.ly/NLDJ5

G1 ‐ 9

Periodic Table

http://bit.ly/k7foR

Images

Image

G1 ‐ 10 Animation Check this out

Notebook Gallery

G1 ‐ 11 Image

Molecules, Compounds

http://bit.ly/NaJm2

G1 ‐ 13 Images

Mixtures Nuts Lemonade

http://bit.ly/ivINE http://bit.ly/rsVRv http://bit.ly/4acyHs

G1 ‐ 15 Image

Properties of Matter

http://bit.ly/Nbm0R

G1 ‐ 17 Animation Elements, Mixtures, Compounds http://bit.ly/QhUr0 G1 ‐ 15 G1 ‐ 15

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Teacher's Notes This class has been designed to cover the topics of Elements, Mixtures and Combinations from Monday August 10th till Friday August 14th.

For further knowledge about this topic: 1. Conduct a thorough search under the topic: Elements, Mixtures and Combinations on the Web, books and magazines.

2. If findings are not specific, ask your teacher for suggestions.

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Objectives • Identify and distinguish between elements, mixtures and compounds.

Note: All, or most, of the objectives will be covered during class time, however the student must be responsible for those objectives not covered or concluded.

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Vocabulary • • • • • • •

Element: Mixture: Solution: Suspension: Combination: Emulsion: Gel:

Note: Most of the vocabulary words will be covered during class time, however the student must be responsible for those words not covered or concluded.

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Link and Learn You can visit the following websites to improve your understanding on the present topic: • • • • • • •

http://bit.ly/17E1ZK http://www.webelements.com/ http://www.chem1.com/acad/webtext/atoms/atpt‐6.html#SIZE http://www.dayah.com/periodic/ http://science‐learning2009.wikispaces.com http://learningandscience.blogspot.com http://libraryatstgeorge.blogspot.com

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Prepared by

Gerardo LAZARO Science Lead Teacher Email: glazaro@sanjorge.edu.pe Wiki: http://science‐learning2009.wikispaces.com Blog: http://learningandscience.blogspot.com Twitter: http://twitter.com/glazaro

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SURVEY If you want to contribute in improving your Chemistry class, click in the survey link:

Term III ‐ 8th A ‐ Class 1 Term III ‐ 8th Alpha ‐ Class 1

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Term III ­ Class 1 Elements, Mixtures and Solutions

Grade: Subject: Date:

8th Grade Chemistry ­ A August 10th, 2009

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1

What was your UNDERSTANDING of the topic: "Elements, Mixtures and Solutions"

A

I understood 25% of the whole topic

B

I understood 50% of the whole topic

C

I understood 75% of the whole topic

D

I understood 100% of the whole topic

E

I didn't understand the class

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2

What was your level of EFFORT to understand the topic?

A

My effort level was 25%

B

My effort level was 50%

C

My effort level was 75%

D

My effort level was 100%

E

I didn't put any effort

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3

What RESOURCES helped you understand the topic?

A

Text

B

Images

C

Animations

D

Videos

E

Teacher's Speech

F

None

G

Other

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4

How does the SMART Board help you understand the topic?

A

It helps me visualize concepts

B

It helps understand difficult concepts

C

Touching things helps me learn

D

Interacting with the information makes it easier to understand

E

I prefer less effects or audiovisual resources

F

It doesn't really help much

G

I don't like it

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Term III ­ Class 1 Elements, Mixtures and Solutions

Grade: Subject: Date:

8th Grade Chemistry ­ Alpha August 10th, 2009

32

1

What was your UNDERSTANDING of the topic: "Elements, Mixtures and Solutions"?

A

I understood 25% of the whole topic

B

I understood 50% of the whole topic

C

I understood 75% of the whole topic

D

I understood 100% of the whole topic

E

I didn't understand the class

33

2

What was your level of EFFORT to understand the topic?

A

My effort level was 25%

B

My effort level was 50%

C

My effort level was 75%

D

My effort level was 100%

E

I didn't put any effort

34

3

What RESOURCES helped you understand the topic?

A

Text

B

Images

C

Animations

D

Videos

E

Teacher's Speech

F

None

G

Other

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4

How does the SMART Board help you understand the topic?

A

It helps me visualize concepts

B

It helps understand difficult concepts

C

Touching things helps me learn

D

Interacting with the information makes it easier to understand

E

I prefer less effects or audiovisual resources

F

It doesn't really help much

G

I don't like it

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