A physical change is characterized by the fact that ___ is formed.

No new substance is formed

True or False: In a physical change, energy such as heat or light is emitted or absorbed.

False. In a physical change, forms of energy such as heat, light, and electricity are neither emitted nor absorbed.

Chemical changes are characterized by the formation of ___ substances with different chemical properties.

New

True or False: A chemical change is reversible, meaning the original substances can be recovered.

False. A chemical change is generally irreversible.

What is an example of a chemical change that involves a color alteration?

The browning of an apple when it is sliced and not consumed immediately.

What is the chemical equation representing the burning of magnesium in oxygen?

Magnesium (Mg) + Oxygen (O2) → Magnesium oxide (MgO)

What is the primary role of the ozone layer in our atmosphere?

The ozone layer serves as protection against harmful ultraviolet radiation from the sun by absorbing this radiation and converting it into oxygen.

Rusting of iron can be prevented by ___ and ___.

Oiling and greasing, painting

True or False: The process of ozone breaking down is a physical change.

False. The process of ozone breaking down can be considered a chemical change.

What process is used to obtain large, pure crystals from solutions?

Crystallization is the process used to obtain large, pure crystals from solutions.