The Particle Model: Density and Changes of State

Vocabulary flashcards covering the particle model of matter, density calculations, measurement techniques, and changes of state.

Density ($\rho$)

The mass per unit volume of a substance, calculated using the formula $\rho = \frac{m}{V}$.

Regular solid volume

The volume of a regular solid (e.g. metal block), calculated as $\text{length} \times \text{width} \times \text{height}$ ($V = l \times w \times h$).

Irregular solid displacement

The method of finding the volume of an irregular solid (e.g. rock) using a measuring container, calculated as $\text{final volume} - \text{initial volume}$.

Meniscus reading

The proper technique for measuring liquid volume with a measuring cylinder, requiring the bottom of the meniscus to be read at eye level.

Internal energy

The energy store of particles, which changes during a change of state.

Melting

A change of state from solid to liquid that absorbs energy, where particles gain energy, overcome forces, and move further apart.

Boiling

A change of state from liquid to gas that absorbs energy, where particles gain energy, overcome forces, and move further apart.

Freezing

A change of state from liquid to solid that releases energy, where particles lose energy and move closer together.

Condensing

A change of state from gas to liquid that releases energy, where particles lose energy and move closer together.

Temperature during a change of state

Stays the same because all energy is used to change the state rather than to change temperature.