Front

Part of an atom that determines its identity

Back

Proton. The number of protons (atomic number) defines the identity of an element.

Front

Type of change when rust forms on an iron object

Back

Chemical. Rust is a result of a chemical reaction between iron and oxygen.

Front

Example of a compound

Back

Water (H2O). Water is made from two hydrogen atoms and one oxygen atom bonded together.

Front

Filtration works best when separating solids of different sizes, like marbles and flour.

Back

Flour and marbles

Front

Visible particles and layers indicate a suspension, not a solution.

Back

Suspension

Front

If salt remains after evaporation, it's a solution (mixture of water and dissolved salt).

Back

Evaporate the water

Front

Boiling water is a physical change—it changes state but not chemical makeup.

Back

Boiling water

Front

Sour milk turning solid indicates a physical change.

Back

Turned solid

Front

The frozen layer on top of the milk can melt into liquid.

Back

Phase changes (like freezing/melting) are physical changes.

Front

Conservation of mass is reflected in a balanced chemical reaction.

Back

CH₄ + O₂ → CO₂ + H₂O.