Basic Chemistry - States and Properties of Matter

Identify the physical states of matter: solid, liquid, and gas.

Matter exists in three physical states: solid, liquid, and gas.
Solids: Have a definite shape and volume. Particles are tightly packed in a rigid structure and only vibrate in fixed positions. Example: Amethyst ( $SiO_2$ ).
Liquids: Have a definite volume, but take the shape of their container. Particles are close together but move slowly around each other.
Gases: Have no definite shape or volume, expanding to fill their container. Particles are far apart and move rapidly.

Characteristic	Solid	Liquid	Gas
Shape	Definite	Container shape	Container shape
Volume	Definite	Definite	Fills container
Particle Arrangement	Fixed, very close	Random, close	Random, far apart
Interactions	Very strong	Strong	Essentially none
Particle Movement	Vibrate in place	Move slowly	Move rapidly
Examples	Ice, salt, iron	Water, oil, vinegar	Water vapor, helium, air

Physical Properties: Characteristics observed without changing the substance's chemical identity (e.g., color, melting point, density).
Physical Properties of Copper ( $Cu$ ):
- State ( $25\,^{\circ}\text{C}$ ): Solid
- Color: Orange-red
- Luster: Shiny
- Melting Point: $1083\,^{\circ}\text{C}$
- Boiling Point: $2567\,^{\circ}\text{C}$
- Conductivity: Excellent for heat and electricity
Physical Changes: Alterations in form, state, or size that keep the chemical identity constant (e.g., boiling water into steam, hammering gold into foil).

Chemical Properties: A substance's ability to react and transform into new substances (e.g., flammability, reactivity with acid or water).
Chemical Changes: Processes where starting materials (reactants) form new substances (products) with distinct properties.
Examples:
- Decomposition: Table salt ( $NaCl$ ) breaks down into sodium ( $Na$ ) metal and chlorine gas ( $Cl_2$ ).
- Rusting: Iron ( $Fe$ ) reacts with oxygen ( $O2$ ) and water to form rust ( $Fe2O_3$ ).
- Combustion: Burning paper or gasoline produces carbon dioxide ( $CO2$ ) and water vapor ( $H2O$ ).
- Souring Milk: Bacteria convert milk sugars into lactic acid.

Category	Physical	Chemical
Property	Observed without changing composition (e.g., color, density).	Ability to form new substances (e.g., flammability, rustability).
Change	Identity stays the same (e.g., melting, cutting).	Identity changes to new substances (e.g., burning, rusting).

Gold hammered into leaf: Physical change (shape changes, identity remains gold).
Gasoline burns in air: Chemical change (forms $CO2$ and $H2O$ ).
Chopping garlic: Physical change (size and shape change only).
Milk turns sour: Chemical change (fermentation forms new chemical substances).
Separating oil and water: Physical change (physical separation based on density).