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Physical or Chemical?
Physical
Chemical
Identity of a Substance
100
Metal rusts - Physical or chemical change?
Chemical
100
What kinds of changes in substances are always physical changes?
Changes of state from a solid to liquid to gas and back. (State changes)
100
Why is it that cooking or baking something is a chemical change?
Chemicals mix together and cause food to harden and/or rise. For example, in making read, baking powder and carbon dioxide react together.
100
A substance that can be separated by physical means
Homogenous mixture
200
Wood burns - Physical or chemical?
Chemical
200
Why is wood burning NOT a physical change?
Why is wood burning NOT a physical change? Wood changes to ash, so it changes the identity of a substance.
200
What is a very common chemical change?
Combustion, cooking/baking, etc.
200
A substance that can be separated by chemical means
Compound
300
An ice cube melts - Physical or chemical?
Physical
300
What are the signs that a physical change has taken place?
Size change, shape change, state change.
300
What are the three main signs that a chemical change has taken place?
The three clues that indicate a chemical change has taken place are a drastic change in color, giving off an odor that wasn’t there previously, and bubbling.
300
A substance that cannot be separated by physical or chemical means
Element
400
Is a burning candle a physical or a chemical change?
It's both a physical and a chemical change. The physical changes of a burning candle are that it’s melting, so it’s going through a state change, and that the size and shape is changing. The chemical changes are that it gives off an odor and a release of light and heat.
400
How do you know for certain that a substance has only gone through physical change and not chemical change?
The substance's identity has not changed.
400
Is chemical change easily reversed or it is difficult to reverse?
Usually it's very difficult to reverse chemical changes.
400
If a substance consists of more than one type of atom chemically combined, then what it is?
It is a compound.
500
Is evaporation a physical or a chemical change?
Evaporation is a physical change. It’s a physical change because the physical properties of the substance are being changed. In this case, it’s a state change, from a liquid to a gas.
500
Is physical change easily reversed or is it difficult to reverse?
It is often easily reversed.
500
When a substance undergoes chemical changes, does the identity of the substance ALWAYS change?
Yes, if a substance underwent chemical changes, the identity of a substance would always change.
500
What does it mean if a substance is immiscible?
It means that it cannot fully mix with another substance. It can't dissolve in another substance.