Reversible and Irreversible Changes
What is a reversible change?
A change that can be changed back to its original state
What does a chemical change do that a physical change does not?
What happens to particles during a physical change?
They move
When is matter created or destroyed?
Never
What process makes a chemical change to food we eat?
Digestion
What is an irreversible change?
A change that can't change back to its original state
Name 1 physical change.
...
What happens to particles during a chemical change?
Atoms rearrange to make different molecules
Why is not matter lost during a physical change?
Atoms move, but there are the same number of atoms after the change.
Why do we need oxygen?
To get get energy from our food
Burning, cooking, rusting, infractions...
Name 2 chemical changes.
...
How can a molecule still be an elemant?
Only one type of atom
Why is no matter lost during a chemical change?
The new molecules contain the same number of atoms.
Carbon dioxide, water vapor, and energy
Name 3 reversible changes in the water cycle.
evaporation, condensation, precipication, freezing ...
What are the signs that a chemical change has happened?
Light, temperature change, colour change, odour, a gas is produced, a solid is produces, explosion
Why is dissolving salt in water not a chemical change?
There is no change to the individual particles.
When does it appear that matter is lost during a physical or chemical change?
When it becomes a gas
What chemical change do plants perform?
photosynthesis
Nane 2 irreversible changes that are happening to Mr. Bohovesky' head.
Gray haior, wrinkles, saggy skin ...
What new substances are produces by burning paper?
Ash, carbon dioxid, and water vapour
Besides creating different molecules, what can happen when chemical bonds between atoms change?
Energy can be released.
If mass is never lost, why do I weight less on the moon.
Name one other thing that can change your weight.
Less gravity
buoyancy in water
Name one chemical change that happens when humans cause air pollution.
Acid rain
Ground level ozone
Greenhouse gases and global warming