1. Write down new vocabulary

2. Stamp Activity 17 & Isotopes

Youtube Periodic Table- Bromine

Title: Creating New Materials

Activity 19

Read B-39Problem: How are reactants changed by a chemical reaction? How are the products different?

Hypothesis/Initial Thoughts:

Background:Chemical Reactions•occur during every day activities like cooking, cleaning and bleaching laundry•can’t be observed at a molecular level•generally use indirect indicators to infer that a chemical reaction has taken place

Color changeFormation of a new substance with properties different

from the original reactant release of a gasheat given off or absorbed light or sound given off

Iron powder and sulfur are mixed. A heated metal rod initiates an exothermic reaction

• Examples of chemical reactions:– Burning fuel to heat homes– Combustion of gasoline to power cars– The human body using a reaction between

food and oxygen to produce carbon dioxide and water, releasing energy

– Baking bread or cookies

Background cont.:

HC C

H O

H

H

Background: Create this molecule Vinyl alcohol

Draw it in your notebook

Link your vinyl alcohols together

• You can use all of these single molecules to build a long chain.

• Use extra bonds to link your molecule to the other molecules.

• You modeled a chemical reaction between vinyl alcohol molecules.

• One function of a model is to make simple representations of complex systems

• Molecular models allow us to visualize what is happening at the molecular level

•You will be using Polyvinyl Alcohol today.

•The long chain is called a polyvinyl alcohol, because “poly-” means many. In any reaction like this, the starting subunit part is called a monomer, which means “one part”, and the resulting chain of many parts is called a polymer, which means “many parts”

We made Polyvinyl Alcohol

• One Vinyl Alcohol Molecule = monomer

• Long Chain Polyvinyl Alcohol = polymer– 1,000-10,000 monomers form a polymer.

• “Poly” means many

• “Mono” means one

Background cont.:

Draw it in your notebook

More monomer links

H

C C

H O

H

H

H

C C

H O

H

H

Polyvinyl Alcohol

More monomer links

Background cont.:

Reactants + Reactant Product + Product

Sodium and Water Demo:

2Na + 2H2O 2NaOH + H2

Reactant: a substance that undergoes change in a chemical reaction

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

Examples of Plastics

• Polypropylene (Blue)

• Polyvinyl Chloride (Green)

• High Density Polyethylene (Red)

• Polystyrene (Yellow)

What do you notice about the names of these materials?

Read Steps 1-8 on B40 to B41

• LEAVE ROOM (AT LEAST 10 LINES) FOR YOUR DATA TABLE!!

What will be our evidence of a chemical reaction?

What are some of the rows that we will need to label on our data table??

What will be our evidence of a chemical reaction?

Color

How does it pour?

Can it be stirred?

Stickiness

Bounciness

Stretchiness

Other Observations

• In this activity you will start with the polymer known as polyvinyl alcohol (PVA) and see how its properties change when it is mixed and reacts chemically with another compound, to change its molecular composition.

• Stir the mixture constantly and slowly until a gel forms

• Clean and dry the materials quickly!!!!• Everyone wash your hands after you

have put away your goggles and gloves

It is the number of cross-links that determines the properties of a polymer

•Which do you think is a harder substance, a polymer with more cross-links or a polymer with fewer cross-links?

The sodium borate created the cross-links with the polyvinyl alcohol

•What do you think would happen to the final polymer if you continued to add sodium borate?

Cross-linked plastics are more rigid

Follow-up

Follow-up• What are the physical properties of the

reactants?

• Describe the physical properties of the product.

• What evidence show a new substance was formed?– change in physical properties indicates an

new substance has been formed