Separating Mixtures
What are the two types of mixtures?
Homogeneous mixtures and heterogeneous mixtures.
Name the three chemical reactions we have studied this unit
Combustion, oxidation, and fermentation.
Liquids can be evaporated by freezing them.
False: By heating them.
If a bike left outside in the rain makes the bike rusty, is it a physical change or chemical change and why?
Rust is a chemical change because the bike cannot be changed back to not being rusty.
It involves electric charges, that travel from one place to another, they can be positive or negative.
Electrical energy/Electricity
Name the four ways of separating mixtures we have studied this unit.
Magnetic separation, filtration, evaporation and distillation.
Oxidation happens when atoms react with ___________ from the atmosphere.
OXYGEN
We can separate solids and liquids using magnetic separation. If false, give an explanation.
False.
When water freezes to make ice. Is this a physical or chemical change? Explain your answer.
It is a physical change because the water is changing its state of matter; it is changing from a liquid to a solid.
Decomposition of sugars and other substances into alcohol, carbon dioxide, or lactic acid.
Fermentation
Distillation is used to separate:
Liquids with different boiling points.
Water in a freezer is a physical or chemical change?
Physical change.
True or False. An electrical current goes from an object to another
True. One common way to produce electric current is through chemical reactions in a battery.
I took a piece of paper and rolled it up into a ball. Is this a physical change or chemical change. Explain your answer.
It is a physical change because a new substance is not formed. It is just changing its shape.
Material or substances increase in volume.
Expansion
Name two examples of each separation method. (except magnetic separation)
Filtration: coffee, oxygen and germs, water and sand...
Evaporation: water and salt, water and sugar.
Distillation: water and ethanol, water and alcohol, petrol...
What types of energy does combustion produce?
Thermal, chemical and light energy
True or False. Salt-water is a mixture that can be separated by distillation.
True. One example of distillation mixture is separating salt water to create pure water and salt.
Is lighting a match a physical or chemical change? Explain your answer.
Lighting a match is a chemical change because the burnt match cannot be changed back.
Changes in the shape when a force is exerted on them.
Deformations
What is the difference between Heterogenous and Homogeneous mixtures?
Heterogenous have visible components and Homogenous don't.
Which of the next foods are produced using fermentation and which ones can suffer oxidation?
Potatoes
Cheese
Yoghurt
Apples
Bananas
Fermentation: cheese, yoghurt, and bread.
Oxidation: apples, bananas, and potatoes.
True or False. Sand and water can be an example of a heterogeneous mixture found in nature.
True. Sand and water is a heterogeneous mixture because sand particles are not uniformly distributed in the water.
A glass breaking is considered to be physical or chemical change?
Physical change because if you break it, it's still glass. It didn't change to another substance.
It is when an electric current flows through a conductor and creates a magnetic field along the conductor.
Electromagnetism