Mistake Master
Home› Unit 3 · Properties of Substances and Mixtures› 3.1· 3.2· 3.3· 3.4· 3.5· 3.6· 3.7· 3.8· 3.9· 3.10· 3.11· 3.12· 3.13

Solids, Liquids, and Gases

▶︎  Watch it animatedinteractive step-through · ~3 min · optional

The three states of matter differ in how their particles are spaced, ordered, and moving. In a solid particles are packed and vibrating in place; in a liquid they stay close but flow past one another; in a gas they are far apart and moving fast and randomly. Those particle-level differences explain the macroscopic properties of shape and volume.

UNIT 3 TOPIC 3.3 • SOLIDS, LIQUIDS, AND GASES PHASE PARTICLE VIEW SOLID MACROSCOPIC VIEW Particles packed in fixed positions; vibrate in place only. Definite shape & volume LIQUID MACROSCOPIC VIEW Particles close but mobile — slide past one another. Definite volume · no fixed shape GAS MACROSCOPIC VIEW Particles far apart, rapid random motion in all directions. Expands to fill its container INCREASING TEMPERATURE (ENERGY) LOW HIGH SOLID LIQUID GAS THE TAKEAWAY As energy (temperature) rises, particles move faster and overcome attractions — spacing grows and phase changes: solid → liquid → gas. AP Chemistry · Unit 3 · Properties of Substances & Mixtures
The three phases at the particle level. Solids hold particles fixed and ordered (definite shape and volume); liquids keep them close but mobile (definite volume, no fixed shape); gases spread them far apart in fast, random motion (no fixed shape or volume).
Phase Particle View · Open the sandbox →

The core skill is reading the particle model correctly: matching a drawing of spacing and motion to the right phase, and not confusing macroscopic behavior with particle behavior. Phase changes rearrange particles and their motion; they do not change the particles themselves.

The work

3 ways in · any order
Lesson
States of Matter ›

Solids, liquids, and gases differ in particle spacing, order, and motion, which sets their shape and volume. The lesson reads the particle model for each phase, then closes with a ten-scenario check.

Skill check · 10 scenarios
Open lesson →
Diagnostic
10-item topic check ›

Ten items on the states of matter: matching particle-level pictures to phases and reasoning from spacing and motion to macroscopic properties.

Not started · 10 items · ~15 min
Start diagnostic →
Targeted Practice
Drill a single misconception ›

Pick one of the failure modes you missed and drill it on its own. The round is adaptive: two correct in a row clears the misconception and moves you to the next.

Take the diagnostic to identify your misconceptions
Diagnostic first