chemical reactions

CHEMICAL REACTIONS

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Definition

1.2. 3. 4. 5. 6. 7. 8.

Types of chemical reacions

Difference between mixture and chemical reaction

SIGNS OF A CHEMICAL REACTION

OXIDATION

COMBUSTION

FERMENTATION

SUMMARY MIND MAP

Matter and how it changes

• Matter is everything around us it has mass and volume.

• A change in shape or form is a physical change

• A change of state is a physical change.

• A new product which is very difficult to or impossible to change back to its orgional substance is a chemical change..

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Chemical reaction

Definition

Atoms within substances are and joined together in different ways. The substances that react together in a chemical reaction are called A is formed.

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reactants

new product

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Chemical reactions

A naturally occuring chemical reation (photosynthesis)

Chemical reactions occur when we cook

Reactant 1 (CO2) + reactant 2 (H2O) Apply THERMAL ENERGY (sunlight) New product (C6H12O6 + O2)

yummy bread

Flour + water + salt

A CHEMICAL REACTION IS NOT THE SAME AS A PHYSICAL CHANGE

• A physical change is a change in shape or state but it is still the same substance
• A chemical change is a change in substance, a new product forms.
• Matter (atoms) is never created or destroyed, it is transformed

The difference between the product of a chemical reation and a mixture is that a chemical reaction is required to re-seperate the components.

In mixtures, simple seperation methods can be used like filtration, evaporation or distillaton

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How do we know a chemical reaction has occured?

EXOTHERMIC REACTION, the product becomes warmer.ENDOTHERMIC REACTION, the product becomes colder

Energy change, a chemical reaction can produce light energy

Chemical reactions can produce gas (rotten eggs)

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A colour change is a sign that a chemical reaction has taken place

Precipitate formation shows a change in composition, it is a sign of a chemical reaction

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Types of chemical reactions

OXIDATION

• is a chemical reaction where the substance changes because oxygen is added
• Metals (iron, Fe) react with oxygen and water, they go rusty.
• Salt speeds up oxidation.
• Oxidation occurs in food. The chemicals in food react with oxygen and the food discolours and breaks down.

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Types of chemical reaction

COMBUSTION

• Is the burning of a substance in the presence of oxygen.
• Energy is produced in the form of heat and light.
• Exothermic reaction
• Heat (thermal energy), fuel and oxygen are required for something to burn.

yeast

Types of chemical reaction

FERMENTATION

• Natural occuring CHEMICAL reaction
• Involves microorganisms
• Fungi (yeast)- bread
• Good bacteria -Yoghurt
• Mould - BLUE CHEESE
• TRANSFORMS sugars into different substances like alcohol and carbon dioxide.
• Useful for preserving food and making food tastier.

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FERMENTATION

• Yeast is a living organism.
• All living organisms need nutrients.
• Yeast (fungus) cells cause fermentation
• They break down sugars
• They produce waste products(carbon dioxide and alcohol)
• It produces a gas and the bread rises.
• Bacteria produce lactic acid and carbon dioxide

Another MINDMAP by Elena Guillen

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