Chemical Reactions: Combustion, fermentation and oxidation.

0. INTRODUCTION

Everything around us is made of matter: our bodies, the air we breathe, the ground we walk on and the water we drink. Matter can’t be created or destroyed; it just changes. Some of the changes it undergoes are physical and others are chemical. During physical changes the appearance of the matter changes, but its chemical properties remain the same. Chemical reactions, such as fermentation or combustion, change a substance into a new one with different properties.

WARM UP!

1. Materials have different properties and this determines how we use them. Look at the different materials and properties in the box, then copy and complete the table in your notebook.

1. REVIEW SUMMERIES:

2. MATTER CHANGES

 "Matter can’t be created or destroyed; it just changes."

Matter changes continuously. It can change shape or form or it can be also transform into different matter. So, some of the changes it undergoes are physical and others are chemical. 

https://www.youtube.com/watch?v=BOr76Zx48QM&sns=em

https://youtu.be/yIJ2qnUOOwQ 

1. Physical changes: shape or form changes but mass and volume stay the same (its chemical properties remain the same). 

Example: when a paper breaks into smaller pieces, changes of state in water...

2. CHEMICAL CHANGES: Matter changes into a new substance with different properties. 

Example: When paper is burn and become ashes,  iron (Fe) rusts when it is exposed to oxygen gas in the air...

Chemical reactions:

You may think that chemical reactions only happen in science labs, but they are actually happening all the time in the everyday world. Every time you eat, your body uses chemical reactions to break down your food into energy. Other examples include metal rusting, wood burning, batteries producing electricity, and photosynthesis in plants...

Combustion, oxidation and fermentation are irreversible changes.

a. Combustion:

In order to maintain combustion (burning) you need three things, fuel, heat and oxygen. If you have all three in the proper proportion you can maintain a continuous state of combustion. Remove one (or reduce one sufficiently) and the triangle of combustion can collapse. 

 b. Fermentation: 

Fermentation is used to make foods such as cheese or bread and drinks such as wine. Fermentation also occurs naturally in sugars in fruits or vegetables, which helps with decomposition. Fermentation is also used to preserve food all over the world. Vegetables, fruit, fish, and meat can all be stored for longer if they are fermented first.

Experiments:

 c. Oxidation

Apples and potatoes oxidise when they are peeled or cut.

MindMap:

ACTIVITIES:

1. What is the main different between Physical and Chemical changes?

2. Which gas is needed for combustion?

3. How do we know if metal has oxidised?

4. What is needed for fermentation? What gas is released during fermentation?

5. Are the following sentences true or false?

a. Combustion needs carbon dioxide to burn matter.

b. Metals react with fire to produce rust.

c. Oxygen is necesary in the process of combustion.

d. Oxidation only occurs in metals.

Voluntary Work:

6. Find out about fermented foods.

7. Find out about combustion and forest/wildland fires.

8. Science Project: Oxidation experiment or fermentation experiment.