Combustion
True or false: Air is 79% oxygen.
False. Air is about 21% oxygen.
What natural defense protects food from oxidation?
It´s skin, for example with different fruits.
Name one food we can make with fermentation:
Cheese, yogurt, bread, pickled vegetables.
What is an example of a colour change in a chemical reaction?
Fruit that turns brown or black.
Metals that change to reddish-brown (rust).
What is fuel? Can you name an example?
It is anything that burns, including wood, gas, and oil.
How does oxidation affect food?
When the food comes in contact with oxygen, the food begins to discolor (usually turns brown or black), and break down.
What do bacteria produce during fermentation?
Lactic acid and carbon dioxide.
What is a precipitate formation?
It is when a solid is formed when you combine two solutions.
What new substances are created after combustion?
Ash and smoke.
How can you prevent some metals from getting rusty?
You protect them from exposure to water. Cover them.
What do fungi produce during fermentation?
Alcohol and carbon dioxide.
What are the four clues that a chemical reaction has happened?
Colour change, energy change, gas formation, and precipitate formation.
What three things are necessary for combustion to happen?
Fuel, oxygen, and heat.
What happens when iron reacts with oxygen and water? What is the new substance called and how does it look?
The iron goes rusty. Rust is a reddish-brown substance that easily breaks apart.
Why do we use fermentation in food?
Fermentation is often used for food preservation.
These three things can cause chemical reactions to happen:
Thermal energy (heat), oxygen, and microorganisms.
What is combustion?
It is a rapid chemical combination of a substance with oxygen. Also called "burning."
What is oxidation?
It´s a chemical reaction where a substance changes because oxygen is added.
How does fermentation occur?
It occurs when there is no oxygen, and involves microorganisms such as bacteria and fungi.
True or false: New products from chemical changes can be separated through filtration or distillation.
False: They can only be separated with another chemical reaction because the particles are chemically linked.