Matter and Chemical Changes - Chemistry Unit

Flashcards covering states of matter, physical changes, and changing states concepts from the lecture notes.

What are the three main states of matter?

Solid, liquid, and gas.

How does a solid's shape behave?

A solid holds its own shape and does not take the shape of its container.

How does a liquid behave in terms of shape?

A liquid takes the shape of the container it is in.

How does a gas behave in terms of shape?

A gas fills the space and shape of its container.

What is a physical change?

A change where a substance changes shape or form but no new substance is produced; usually reversible.

Name some types of physical changes.

Shape/form changes, expanding, contracting, change of state, dissolving/mixing substances.

What is expansion?

An increase in volume when a substance is heated; occurs in solids, liquids, and gases; no new substance is formed.

What is contraction?

A decrease in volume when a substance is cooled.

What is melting?

Solid turning into a liquid.

What is freezing?

Liquid turning into a solid.

What is evaporation?

Liquid turning into a gas.

What is condensation?

Gas turning into a liquid.

What is sublimation?

Solid turning directly into a gas.

What is deposition?

Gas turning directly into a solid.

Do substances sometimes skip a step in changing states?

Yes. Sublimation (solid to gas) and deposition (gas to solid) can occur directly.

How do elements, compounds, and mixtures differ at the particle level?

Elements are pure substances with one type of atom; compounds are chemically bonded combinations of elements; mixtures are physical blends not chemically bonded.

How does particle arrangement relate to states of matter?

Solids have tightly packed particles, liquids have looser packing, and gases have widely spaced particles that move freely.

What is the difference between chemical and physical changes?

Chemical changes form new substances; physical changes do not; physical changes are usually reversible.

What role do temperature and energy play in states of matter?

They influence particle motion and spacing; heating increases energy leading to expansion and possible phase changes; cooling decreases energy leading to contraction or freezing.

What is an example of a physical change when crushing a tablet?

Crushing a tablet changes its form but not its identity; it remains the same substance.

What are the six processes listed for changing states of matter?

Melting, freezing, evaporation, condensation, sublimation, and deposition.

What happens to solids, liquids, and gases when heated and when cooled?

Heating causes expansion; cooling causes contraction.