•Objective: Tell the difference between a physical and a chemical change

Warm-up: -What are the 5 indicators? (Try without your notes)

Next:Quiz your partner to see if they know the definitions of a physical &

chemical change.

• What is a physical change:

• What is a chemical change:

A change in appearance only that does NOT make a new substance.

A change that causes a new substance to be formed, must have at least one indicator.

Tell the BASIC idea/definition for the following.

Name: ____________________

Class: ____________________

Vocabulary:

Chemical Equation –

Reactants –

Products –

A chemical reaction occurs when two or more chemical substances are combined together. This means that

the atoms that were joined together in the reactants ____________ ____________ then ____________

themselves and ____________ to make a __________ _____________. One or more of the reactants may

be transformed into one or more new products. These new products are quite __________ from the original

reactants.

5 Signs of a Chemical Reaction:

1. (T) _____________ 2. (C) _____________ 3. (G) _____________ 4. (L) _____________ 5. (P) ____________

Complete this worksheet

using the following 3

slides.

Chemical Equation – Using symbols to summarize a chemical reaction .

Reactants – Materials at the beginning of a chemical reaction.

Products – Materials at the end of a chemical reaction.

Chemical Reactions:

A chemical reaction occurs when two or more chemical substances are combined together. This means that the atoms that were joined together in the reactant break apart then rearrange themselves and reconnect to make a new substance. One or more substances may be transformed into one or more new substances. This new substance is quite different from the original substances.

Reactant + Reactant ----> Product

Some products of chemical reactions are heat, light, sound and changes in color.

Chemical reactions create new substances. But, how do you know a new substance was formed?

Light Produced

Color ChangePrecipitate

Temperature Change

Gas Produced

Discovery Education: Fizz, Foam & Flames

•“ESC” button on keyboard•Double click “Computer” icon•Go to student apps R drive•Double click on Discovery•Click on Assignments•Click on Fizz Foam & Flames•Complete worksheet

Let’s look at some demonstration pictures on the next 3 slides and identify how we know that a chemical reaction has occurred.

On the “CHEMICAL REACTIONS Examples” Worksheet:

•Circle the indicators you “saw” that tells you a chemical reaction occurred.

http://www.jce.divched.org/video/precipitation-reaction-sodium-iodide-and-mercuryii-chloride

1. Sodium Iodide and Mercury(II) Chloride

Sodium Iodide (pale yellow)

Mercury (II) chloride (colorless)

HgCl2(aq) + 2NaI(aq) --> HgI2(s) + 2NaCl(aq)

Adding very pale yellow sodium iodide to colorless mercury(II) chloride produces an orange precipitate.

Hg Cl

I Na

When nitrogen triiodide, the dark colored solid, is dry, it is very sensitive to touch or any vibration. Simply touching it with a feather causes it to explode or detonate.

One detonation causes another to occur. One product of the reaction is violet iodine vapor (gas).

2NI3 N2 + 3I2

http://www.jce.divched.org/video/nitrogen-triiodide-detonation

2. Nitrogen Triiodide Detonation

•https://imaginationstationtoledo.org/content/2011/07/burning-magnesium-in-dry-ice/

3. Magnesium and Carbon DioxideMagnesium is placed in a cavity in a block of dry ice. The magnesium is ignited

and covered by another block of dry ice. Despite the absence of air, the magnesium continues to glow, due to its reaction with carbon dioxide. Because of

this reaction, carbon dioxide cannot be used to extinguish magnesium fires.The reaction products are white magnesium oxide and black carbon.

Chemical Reaction Examples

1. Sodium Iodide (NaI) and Mercury(II) Chloride (HgCl2)

2. Nitrogen Triiodide (NI3) Detonation

3. Magnesium (Mg) and Carbon Dioxide (CO2)

• Color change• Precipitate (Orange)

• Color Change• Gas produced

• Color change• Temperature change• Light

What 5 things tell you that a

chemical reaction likely

occurred?